{"669507":{"#nid":"669507","#data":{"type":"news","title":"Claire Berger Receives one of France\u2019s Highest Civilian Honors in Science, Scientific Diplomacy","body":[{"value":"\u003Cp\u003E\u003Ca href=\u0022https:\/\/physics.gatech.edu\/user\/claire-berger\u0022\u003EClaire Berger\u003C\/a\u003E is a professor of the practice in the \u003Ca href=\u0022https:\/\/physics.gatech.edu\/\u0022\u003ESchool of Physics\u003C\/a\u003E, a research pioneer who has helped to establish deeper collaboration between the U.S. and French scientific communities, and now, she\u2019s the latest recipient of one of the oldest and highest honors from the French government.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe \u003Ca href=\u0022https:\/\/atlanta.consulfrance.org\/-english-\u0022\u003EConsulate General of France in Atlanta\u003C\/a\u003E has announced that Berger has been awarded the \u003Ca href=\u0022https:\/\/amopa.asso.fr\/lordre-des-palmes-academiques\/\u0022\u003EChevalier dans L\u0027Ordre des Palmes Acad\u00e9miques\u003C\/a\u003E for her \u201cexceptional dedication and significant accomplishments in the field of science and education,\u201d says \u003Ca href=\u0022https:\/\/atlanta.consulfrance.org\/the-consulate-general-welcomes-its-new-attache-for-science-and-technology\u0022\u003ERami Abi Akl\u003C\/a\u003E, French attach\u00e9 for science and technology in Atlanta.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe Palmes Acad\u00e9miques is presented to French citizens and non-citizens who have made significant contributions to French education, science, and culture. The first Palmes Acad\u00e9miques was presented by Napoleon in 1808.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EBerger\u2019s \u201cpioneering work in physics, particularly on graphene, has not only advanced scientific knowledge, but also served as an inspiration to others in her field,\u201d Abi Akl says.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EIn addition to her research and classes at Georgia Tech, Berger is Director of Research at the \u003Ca href=\u0022https:\/\/www.cnrs.fr\/en\/cnrs\u0022\u003EFrench National Center for Scientific Research (CNRS)\u003C\/a\u003E, which has been home to 12 Nobel Prize and 10 Fields Medal winners. Berger\u2019s affiliation is with the CNRS International Research Lab, with its main campus at \u003Ca href=\u0022https:\/\/europe.gatech.edu\/en\/campuses\/metz\u0022\u003EGeorgia Tech-Europe\u003C\/a\u003E in Metz, France, and an affiliated lab at Georgia Tech\u2019s Atlanta campus.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EApproximately 50 colleagues from both countries have conducted collaborative research at both Georgia Tech campuses, thanks to Berger\u2019s efforts.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u201cHer selection for this honor also reflects her remarkable impact on both the American and French scientific communities,\u201d Abi Akl says. \u201cHer collaborative efforts and contributions to scientific research have fostered strong ties between France and the United States, strengthening the bonds of scientific diplomacy.\u201d\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u201cA very big thank you to the French General Consulate in Atlanta for submitting my name for this distinctive honor,\u201d Berger recently shared.  \u201cAmong other funding agencies and foundations, I am particularly grateful to the French Embassy for their partnership grants that funded travel and helped collaboration between almost 60 faculty members, postdoctoral scholars, and students.\u201d\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u201cI also want to thank Georgia Tech and the School of Physics for their full support,\u201d she added. \u201cAll that travel and dedicated lab work wouldn\u2019t have happened without the love and support at home from my husband and our three sons.\u201d\u003C\/p\u003E\r\n\r\n\u003Ch4\u003EAbout Claire Berger\u003C\/h4\u003E\r\n\r\n\u003Cp\u003EBerger was born in Paris, France, and received her Ph.D. from the Universit\u00e9 Grenoble Alpes. She joined Georgia Tech in 2001, and she quickly established herself as a noted researcher of the electronic properties of graphene, a material with a flat, two-dimensional structure that is touted as a potential successor to silicon in computer processors.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EBerger and School of Physics Regents\u2019 Professor \u003Ca href=\u0022https:\/\/physics.gatech.edu\/user\/walter-de-heer\u0022\u003EWalter de Heer\u003C\/a\u003E are working on graphene discoveries that could lead to smaller, more energy-efficient processing that is expected to usher in a new era of quantum and high performance computing.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EWalter de Heer welcomed Berger into his lab when she arrived at Georgia Tech, she says. \u201cI want to thank him for being an incredible team leader in this adventure, for his continuous support, his insights, dedication and passion for science.\u201d\u003C\/p\u003E\r\n\r\n\u003Cp\u003EBerger co-authored the first article demonstrating the two-dimensional properties of graphene and a possible electronics platform for the material. Berger, de Heer, and School of Physics Professor \u003Ca href=\u0022https:\/\/physics.gatech.edu\/user\/phillip-first\u0022\u003EPhillip First\u003C\/a\u003E also co-authored the first patent for graphene electronics in 2003.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EShe is the co-author of more than 200 publications in international journals. From 2014 to 2019, she was among the top one percent \u003Ca href=\u0022https:\/\/cos.gatech.edu\/news\/georgia-tech-researchers-2018-highly-cited-researchers-list\u0022\u003Emost cited researchers\u003C\/a\u003E in physics.\u003C\/p\u003E\r\n\r\n\u003Ch4\u003EIn good company with another Atlanta Palmes winner\u003C\/h4\u003E\r\n\r\n\u003Cp\u003EBerger says she was given the letter by the General Consul of Atlanta announcing her award during an event at the Embassy. \u201cI was so surprised by the nomination that I was fumbling trying to find my words. This was a great \u2014 and a bit embarrassing \u2014 moment at the same time.\u201d\u003C\/p\u003E\r\n\r\n\u003Cp\u003EOne of her good friends, \u003Ca href=\u0022https:\/\/www.linkedin.com\/in\/bill-moon-95724a57\u0022\u003EBill Moon\u003C\/a\u003E, is a fellow Palmes Acad\u00e9miques winner for promoting French language instruction at private and public schools in Atlanta and Decatur. \u201cHe founded the \u003Ca href=\u0022https:\/\/icsgeorgia.org\/\u0022\u003EInternational Community School\u003C\/a\u003E in Clarkston, Georgia, a public charter elementary school serving the needs of U.S. and refugee families now living in DeKalb County, and he continues to be active in the service of communities,\u201d Berger says. \u201cTo be awarded the same medal as Bill is an incredible honor.\u201d\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003C\/p\u003E\r\n","summary":"","format":"limited_html"}],"field_subtitle":[{"value":"Physicist Claire Berger has been awarded the Chevalier dans L\u0027ordre des Palmes Acad\u00e9miques for her groundbreaking graphene research \u2014 and her work on strengthening ties between U.S. and French scientists."}],"field_summary":[{"value":"\u003Cp\u003EPhysicist Claire Berger has been awarded the Chevalier dans L\u0027ordre des Palmes Acad\u00e9miques for her groundbreaking graphene research \u2014 and her work on strengthening ties between U.S. and French scientists.\u003C\/p\u003E\r\n","format":"limited_html"}],"field_summary_sentence":[{"value":"Physicist Claire Berger has been awarded the Chevalier dans L\u0027ordre des Palmes Acad\u00e9miques for her groundbreaking graphene research \u2014 and her work on strengthening ties between U.S. and French scientists."}],"uid":"34434","created_gmt":"2023-09-07 14:12:56","changed_gmt":"2023-09-22 16:17:27","author":"Renay San Miguel","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2023-09-19T00:00:00-04:00","iso_date":"2023-09-19T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"671634":{"id":"671634","type":"image","title":"Claire Berger headshot.jpg","body":"\u003Cp\u003EClaire Berger\u003C\/p\u003E\r\n","created":"1694106640","gmt_created":"2023-09-07 17:10:40","changed":"1694106640","gmt_changed":"2023-09-07 17:10:40","alt":"Claire Berger","file":{"fid":"254734","name":"Claire Berger headshot.jpg","image_path":"\/sites\/default\/files\/2023\/09\/07\/Claire%20Berger%20headshot.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/2023\/09\/07\/Claire%20Berger%20headshot.jpg","mime":"image\/jpeg","size":1879304,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2023\/09\/07\/Claire%20Berger%20headshot.jpg?itok=WaDwpMMp"}},"671742":{"id":"671742","type":"image","title":"Walter de Heer and Claire Berger with a model of how computer chip material is made (Photo Jess Hunt-Ralston).jpg","body":"\u003Cp\u003EWalter de Heer and Claire Berger with a model of how computer chip material is made (Photo Jess Hunt-Ralston)\u003C\/p\u003E\r\n","created":"1695136450","gmt_created":"2023-09-19 15:14:10","changed":"1695136450","gmt_changed":"2023-09-19 15:14:10","alt":"Walter de Heer and Claire Berger with a model of how computer chip material is made (Photo Jess Hunt-Ralston)","file":{"fid":"254852","name":"Walter de Heer and Claire Berger with a model of how computer chip material is made (Photo Jess Hunt-Ralston).jpg","image_path":"\/sites\/default\/files\/2023\/09\/19\/Walter%20de%20Heer%20and%20Claire%20Berger%20with%20a%20model%20of%20how%20computer%20chip%20material%20is%20made%20%28Photo%20Jess%20Hunt-Ralston%29.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/2023\/09\/19\/Walter%20de%20Heer%20and%20Claire%20Berger%20with%20a%20model%20of%20how%20computer%20chip%20material%20is%20made%20%28Photo%20Jess%20Hunt-Ralston%29.jpg","mime":"image\/jpeg","size":8019542,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2023\/09\/19\/Walter%20de%20Heer%20and%20Claire%20Berger%20with%20a%20model%20of%20how%20computer%20chip%20material%20is%20made%20%28Photo%20Jess%20Hunt-Ralston%29.jpg?itok=qs__L0wI"}},"671743":{"id":"671743","type":"image","title":"Chevalier dans 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Researchers List"},{"url":"https:\/\/cos.gatech.edu\/hg\/item\/599807","title":"Georgia Tech Faculty in 2017 Highly Cited Researchers List"}],"groups":[{"id":"1278","name":"College of Sciences"},{"id":"126011","name":"School of Physics"}],"categories":[{"id":"130","name":"Alumni"},{"id":"150","name":"Physics and Physical Sciences"},{"id":"135","name":"Research"},{"id":"134","name":"Student and Faculty"}],"keywords":[{"id":"4896","name":"College of Sciences"},{"id":"166937","name":"School of Physics"},{"id":"176495","name":"Claire Berger"},{"id":"176502","name":"Walter de Heer"},{"id":"193025","name":"Chevalier dans L\u0027Ordre des Palmes Acad\u00e9miques"},{"id":"429","name":"graphene"},{"id":"75301","name":"French Embassy"},{"id":"193026","name":"French National Center for Scientific Research"},{"id":"192249","name":"cos-community"},{"id":"192251","name":"cos-quantum"}],"core_research_areas":[{"id":"39471","name":"Materials"},{"id":"39501","name":"People and Technology"}],"news_room_topics":[{"id":"71881","name":"Science and Technology"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EWriter: Renay San Miguel\u003Cbr \/\u003E\r\nCommunications Officer II\/Science Writer\u003Cbr \/\u003E\r\nCollege of Sciences\u003Cbr \/\u003E\r\n404-894-5209\u003C\/p\u003E\r\n\r\n\u003Cp\u003EEditor: Jess Hunt-Ralston\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n","format":"limited_html"}],"email":["renay.san@cos.gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"626340":{"#nid":"626340","#data":{"type":"news","title":"Platinum-Graphene Atomically-thin Fuel Cell Catalysts Show Superior Stability Over Bulk Platinum","body":[{"value":"\u003Cp\u003EFilms of platinum only two atoms thick supported by graphene could enable fuel cell catalysts with unprecedented catalytic activity and longevity, according to a study published recently by researchers at the Georgia Institute of Technology.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EPlatinum is one of the most commonly used catalysts for fuel cells because of how effectively it enables the oxidation reduction reaction at the center of the technology. But its high cost has spurred research efforts to find ways to use smaller amounts of it while maintaining the same catalytic activity.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;There\u0026rsquo;s always going to be an initial cost for producing a fuel cell with platinum catalysts, and it\u0026rsquo;s important to keep that cost as low as possible,\u0026rdquo; said Faisal Alamgir, an associate professor in Georgia Tech\u0026rsquo;s School of Materials Science and Engineering. \u0026ldquo;But the real cost of a fuel cell system is calculated by how long that system lasts, and this is a question of durability.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;Recently there\u0026rsquo;s been a push to use catalytic systems without platinum, but the problem is that there hasn\u0026rsquo;t been a system proposed so far that simultaneously matches the catalytic activity and the durability of platinum,\u0026rdquo; Alamgir said.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe Georgia Tech researchers tried a different strategy. In the study, which was published on September 18 in the journal\u0026nbsp;\u003Cem\u003EAdvanced Functional Materials\u003C\/em\u003E and supported by the National Science Foundation, they describe creating several systems that used atomically-thin films of platinum supported by a layer of graphene \u0026ndash; effectively maximizing the total surface area of the platinum available for catalytic reactions and using a much smaller amount of the precious metal.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EMost platinum-based catalytic systems use nanoparticles of the metal chemically bonded to a support surface, where surface atoms of the particles do most of the catalytic work, and the catalytic potential of the atoms beneath the surface is never utilized as fully as the surface atoms, if at all.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EAdditionally, the researchers showed that the new platinum films that are at least two atoms thick outperformed nanoparticle platinum in the dissociation energy, which is a measure of the energy cost of dislodging a surface platinum atom. That measurement suggests those films could make potentially longer-lasting catalytic systems.\u003C\/p\u003E\r\n\r\n\u003Cp\u003ETo prepare the atomically-thin films, the researchers used a process called electrochemical atomic layer deposition to grow platinum monolayers on a layer of graphene, creating samples that had one, two or three atomic layers of atoms. The researchers then tested the samples for dissociation energy and compared the results to the energy of a single atom of platinum on graphene as well as the energy from a common configurations of platinum nanoparticles used in catalysts.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;The fundamental question at the heart of this work was whether it was possible that a combination of metallic and covalent bonding can render the platinum atoms in a platinum-graphene combination more stable than their counterparts in bulk platinum used commonly in catalysts that are supported by metallic bonding,\u0026rdquo; said Seung Soon Jang, an associate professor in the School of Materials Science and Engineering.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe researchers found that the bond between neighboring platinum atoms in the film essentially combines forces with the bond between the film and the graphene layer to provide reinforcement across the system. That was especially true in the platinum film that was two atoms thick.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;Typically metallic films below a certain thickness are not stable because the bonds between them are not directional, and they tend to roll over each other and conglomerate to form a particle,\u0026rdquo; Alamgir said. \u0026ldquo;But that\u0026rsquo;s not true with graphene, which is stable in a two-dimensional form, even one atom thick, because it has very strong covalent directional bonds between its neighboring atoms. So this new catalytic system could leverage the directional bonding of the graphene to support an atomically-thin film of platinum.\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EFuture research will involve further testing of how the films behave in a catalytic environment. The researchers found in earlier research on graphene-platinum films that the material behaves similarly in catalytic reactions regardless of which side \u0026ndash; graphene or platinum \u0026ndash; is the exposed active surface.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;In this configuration, the graphene is not acting as a separate entity from the platinum,\u0026rdquo; Alamgir said. \u0026ldquo;They\u0026rsquo;re working together as one. So we believe that if you\u0026rsquo;re exposing the graphene side, you get the same catalytic activity and you could further protect the platinum, potentially further enhancing durability.\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cem\u003EThis research was supported by the National Science Foundation (NSF) under grant Nos. 1103827 and 106913. The content is solely the responsibility of the authors and does not necessarily represent the official views of the sponsoring organizations.\u003C\/em\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003ECITATION\u003C\/strong\u003E: \u0026nbsp;Ji Il Choi, Ali Abdelhafiz, Parker Buntin, Adam Vitale, Alex Robertson, Jamie Warner, Seung Soon Jang and Faisal M. Alamgir, \u0026ldquo;Contiguous and Atomically-Thin Pt Film with Supra-bulk Behavior Through Graphene-Imposed Epitaxy,\u0026rdquo; (Advanced Functional Materials, September 2019).\u0026nbsp;http:\/\/dx.doi.org\/10.1002\/adfm.201902274\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"Films of platinum only two atoms thick supported by graphene could enable fuel cell catalysts with unprecedented catalytic activity and longevity, according to a study published recently by researchers at the Georgia Institute of Technology."}],"uid":"31758","created_gmt":"2019-09-18 14:07:50","changed_gmt":"2020-01-07 15:02:52","author":"Josh Brown","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2019-09-18T00:00:00-04:00","iso_date":"2019-09-18T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"626336":{"id":"626336","type":"image","title":"Seung Soon Jang, Faisal Alamgir and Ji Il Choi","body":null,"created":"1568813161","gmt_created":"2019-09-18 13:26:01","changed":"1568813178","gmt_changed":"2019-09-18 13:26:18","alt":"","file":{"fid":"238455","name":"20C10200-P11-001.jpg","image_path":"\/sites\/default\/files\/images\/20C10200-P11-001_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/20C10200-P11-001_0.jpg","mime":"image\/jpeg","size":494059,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/20C10200-P11-001_0.jpg?itok=DnRQjXO9"}},"626337":{"id":"626337","type":"image","title":"Seung Soon Jang, Faisal Alamgir and Ji Il Choi","body":null,"created":"1568813243","gmt_created":"2019-09-18 13:27:23","changed":"1568813243","gmt_changed":"2019-09-18 13:27:23","alt":"","file":{"fid":"238456","name":"20C10200-P11-003.jpg","image_path":"\/sites\/default\/files\/images\/20C10200-P11-003.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/20C10200-P11-003.jpg","mime":"image\/jpeg","size":681560,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/20C10200-P11-003.jpg?itok=seJo0PYo"}},"626338":{"id":"626338","type":"image","title":"Seung Soon Jang, Faisal Alamgir and Ji Il Choi","body":null,"created":"1568813327","gmt_created":"2019-09-18 13:28:47","changed":"1568813327","gmt_changed":"2019-09-18 13:28:47","alt":"","file":{"fid":"238457","name":"20C10200-P11-008.jpg","image_path":"\/sites\/default\/files\/images\/20C10200-P11-008.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/20C10200-P11-008.jpg","mime":"image\/jpeg","size":630771,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/20C10200-P11-008.jpg?itok=AKSCN_nI"}},"626339":{"id":"626339","type":"image","title":"Ali Abdelhafiz","body":null,"created":"1568815302","gmt_created":"2019-09-18 14:01:42","changed":"1568815302","gmt_changed":"2019-09-18 14:01:42","alt":"","file":{"fid":"238458","name":"IMG_5972.JPG","image_path":"\/sites\/default\/files\/images\/IMG_5972.JPG","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/IMG_5972.JPG","mime":"image\/jpeg","size":322725,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/IMG_5972.JPG?itok=Q1yeNsfl"}}},"media_ids":["626336","626337","626338","626339"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"135","name":"Research"}],"keywords":[{"id":"429","name":"graphene"},{"id":"2044","name":"Fuel Cell"},{"id":"182380","name":"platinum catalyst"}],"core_research_areas":[{"id":"39531","name":"Energy and Sustainable Infrastructure"},{"id":"39471","name":"Materials"}],"news_room_topics":[{"id":"71881","name":"Science and Technology"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Ca href=\u0022mailto:john.toon@comm.gatech.edu\u0022\u003EJohn Toon\u003C\/a\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003EResearch News\u003C\/p\u003E\r\n","format":"limited_html"}],"email":["john.toon@comm.gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"591366":{"#nid":"591366","#data":{"type":"news","title":"High Temperature Step-by-Step Process Makes Graphene from Ethene","body":[{"value":"\u003Cp\u003EAn international team of scientists has developed a new way to produce single-layer graphene from a simple precursor: ethene \u0026ndash; also known as ethylene \u0026ndash; the smallest alkene molecule, which contains just two atoms of carbon.\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EBy heating the ethene in stages to a temperature of slightly more than 700 degrees Celsius -- hotter than had been attempted before \u0026ndash; the researchers produced pure layers of graphene on a rhodium catalyst substrate. The stepwise heating and higher temperature overcame challenges seen in earlier efforts to produce graphene directly from hydrocarbon precursors.\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EBecause of its lower cost and simplicity, the technique could open new potential applications for graphene, which has attractive physical and electronic properties. The work also provides a novel mechanism for the self-evolution of carbon cluster precursors whose diffusional coalescence results in the formation of the graphene layers.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe research, reported as the cover article in the May 4 issue of the \u003Cem\u003EJournal of Physical Chemistry C\u003C\/em\u003E, was conducted by scientists at the Georgia Institute of Technology, Technische Universit\u0026auml;t M\u0026uuml;nchen in Germany, and the University of St. Andrews in Scotland. In the United States, the research was supported by the U.S. Air Force Office of Scientific Research and the U.S. Department of Energy\u0026rsquo;s Office of Basic Energy Sciences.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;Since graphene is made from carbon, we decided to start with the simplest type of carbon molecules and see if we could assemble them into graphene,\u0026rdquo; explained Uzi Landman, a Regents\u0026rsquo; Professor and F.E. Callaway endowed chair in the Georgia Tech School of Physics who headed the theoretical component of the research. \u0026ldquo;From small molecules containing carbon, you end up with macroscopic pieces of graphene.\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EGraphene is now produced using a variety of methods including chemical vapor deposition, evaporation of silicon from silicon carbide \u0026ndash; and simple exfoliation of graphene sheets from graphite. A number of earlier efforts to produce graphene from simple hydrocarbon precursors had proven largely unsuccessful, creating disordered soot rather than structured graphene.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EGuided by a theoretical approach, the researchers reasoned that the path from ethene to graphene would involve formation of a series of structures as hydrogen atoms leave the ethene molecules and carbon atoms self-assemble into the honeycomb pattern that characterizes graphene. To explore the nature of the thermally-induced rhodium surface-catalyzed transformations from ethene to graphene, experimental groups in Germany and Scotland raised the temperature of the material in steps under ultra-high vacuum. They used scanning-tunneling microscopy (STM), thermal programed desorption (TPD) and high-resolution electron energy loss (vibrational) spectroscopy (HREELS) to observe and characterize the structures that form at each step of the process.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EUpon heating, ethene adsorbed onto the rhodium catalyst evolves via coupling reactions to form segmented one-dimensional polyaromatic hydrocarbons (1D-PAH). Further heating leads to dimensionality crossover \u0026ndash; one dimensional to two dimensional structures \u0026ndash; and dynamical restructuring processes at the PAH chain ends with a subsequent activated detachment of size-selective carbon clusters, following a mechanism revealed through first-principles quantum mechanical \u0026nbsp;simulations. \u0026nbsp;Finally, rate-limiting diffusional coalescence of these dynamically self-evolved cluster-precursors leads to condensation into graphene with high purity.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EAt the final stage before the formation of graphene, the researchers observed nearly round disk-like clusters containing 24 carbon atoms, which spread out to form the graphene lattice. \u0026ldquo;The temperature must be raised within windows of temperature ranges to allow the requisite structures to form before the next stage of heating,\u0026rdquo; Landman explained. \u0026ldquo;If you stop at certain temperatures, you are likely to end up with coking.\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EAn important component is the dehydrogenation process which frees the carbon atoms to form intermediate shapes, but some of the hydrogen resides temporarily on, or near, the metal catalyst surface and it assists in subsequent bond-breaking process that lead to detachment of the 24-carbon cluster-precursors. \u0026nbsp;\u0026ldquo;All along the way, there is a loss of hydrogen from the clusters,\u0026rdquo; said Landman. \u0026ldquo;Bringing up the temperature essentially \u0026lsquo;boils\u0026rsquo; the hydrogen out of the evolving metal-supported carbon structure, culminating in graphene.\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe resulting graphene structure is adsorbed onto the catalyst. It may be useful attached to the metal, but for other applications, a way to remove it will have to be developed. Added Landman: \u0026ldquo;This is a new route to graphene, and the possible technological application is yet to be explored.\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EBeyond the theoretical research, carried out by Bokwon Yoon and Landman at the Georgia Tech Center for Computational Materials Science, the experimental work was done in the laboratory of Professor Renald Schaub at the University of St. Andrews and in the laboratory of Professor Ueli Heiz and Friedrich Esch at the Technische Universit\u0026auml;t M\u0026uuml;nchen. Other co-authors included Bo Wang, Michael K\u0026ouml;nig, Catherine J. Bromley, Michael-John Treanor, Jos\u0026eacute; A. Garrido Torres, Marco Caffio, Federico Grillo, Herbert Fr\u0026uuml;cht, and Neville V. Richardson.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cem\u003EThe work at the Georgia Institute of Technology was supported by the Air Force Office of Scientific Research through Grant FA9550-14-1-0005 and by the Office of Basic Energy Sciences of the U.S. Department of Energy through Grant FG05-86ER45234. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the sponsoring organizations.\u003C\/em\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003ECITATION\u003C\/strong\u003E: Bo Wang, et al., \u0026ldquo;Ethene to Graphene: Surface Catalyzed Chemical Pathways, Intermediates, and Assembly,\u0026rdquo; (Journal of Physical Chemistry C). http:\/\/dx.doi.org\/10.1021\/acs.jpcc.7b01999\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EResearch News\u003Cbr \/\u003E\r\nGeorgia Institute of Technology\u003Cbr \/\u003E\r\n177 North Avenue\u003Cbr \/\u003E\r\nAtlanta, Georgia \u0026nbsp;30332-0181 \u0026nbsp;USA\u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986) (jtoon@gatech.edu) or Ben Brumfield (404-385-1933) (ben.brumfield@comm.gatech.edu).\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EAn international team of scientists has developed a new way to produce single-layer graphene from a simple precursor: ethene \u0026ndash; also known as ethylene \u0026ndash; the smallest alkene molecule, which contains just two atoms of carbon.\u0026nbsp;\u003C\/p\u003E\r\n","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have developed a new way to produce single-layer graphene from a simple precursor: ethene."}],"uid":"27303","created_gmt":"2017-05-04 17:39:48","changed_gmt":"2017-05-04 18:12:52","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2017-05-04T00:00:00-04:00","iso_date":"2017-05-04T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"591362":{"id":"591362","type":"image","title":"Ethene changing to graphene","body":null,"created":"1493918994","gmt_created":"2017-05-04 17:29:54","changed":"1493918994","gmt_changed":"2017-05-04 17:29:54","alt":"Sequence shows graphene formed from ethene","file":{"fid":"225354","name":"ethene-graphene-fig3.jpg","image_path":"\/sites\/default\/files\/images\/ethene-graphene-fig3.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/ethene-graphene-fig3.jpg","mime":"image\/jpeg","size":297857,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/ethene-graphene-fig3.jpg?itok=ySyy25v8"}},"591365":{"id":"591365","type":"image","title":"Dehydrogenation process","body":null,"created":"1493919215","gmt_created":"2017-05-04 17:33:35","changed":"1493919215","gmt_changed":"2017-05-04 17:33:35","alt":"Dehydrogenation process for creating graphene","file":{"fid":"225356","name":"ethene-graphene-fig1.jpg","image_path":"\/sites\/default\/files\/images\/ethene-graphene-fig1.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/ethene-graphene-fig1.jpg","mime":"image\/jpeg","size":809194,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/ethene-graphene-fig1.jpg?itok=0ZzqveYK"}}},"media_ids":["591362","591365"],"groups":[{"id":"1278","name":"College of Sciences"},{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"135","name":"Research"},{"id":"141","name":"Chemistry and Chemical Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"429","name":"graphene"},{"id":"174348","name":"precursor"},{"id":"174347","name":"ethene"},{"id":"174350","name":"alkene"},{"id":"9180","name":"Uzi Landman"}],"core_research_areas":[{"id":"39451","name":"Electronics and Nanotechnology"},{"id":"39471","name":"Materials"}],"news_room_topics":[{"id":"71881","name":"Science and Technology"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\r\n\r\n\u003Cp\u003EResearch News\u003C\/p\u003E\r\n\r\n\u003Cp\u003E(404) 894-6986\u003C\/p\u003E\r\n","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"453401":{"#nid":"453401","#data":{"type":"news","title":"Disappearing Carbon Circuits on Graphene Could Have Security, Biomedical Uses","body":[{"value":"\u003Cp\u003EIn the television drama \u201cMission Impossible,\u201d instructions for the mission were delivered on an audio tape that destroyed itself immediately after being played. Should that series ever be revived, its producers might want to talk with Georgia Institute of Technology professor Andrei Fedorov about using his \u201cdisappearing circuits\u201d to deliver the instructions.\u003C\/p\u003E\u003Cp\u003EUsing carbon atoms deposited on graphene with a focused electron beam process, Fedorov and collaborators have demonstrated a technique for creating dynamic patterns on graphene surfaces. The patterns could be used to make reconfigurable electronic circuits, which evolve over a period of hours before ultimately disappearing into a new electronic state of the graphene. Graphene is also made up of carbon atoms, but in a highly-ordered form.\u003C\/p\u003E\u003Cp\u003EReported in the journal \u003Cem\u003ENanoscale\u003C\/em\u003E, the research was primarily supported by the U.S. Department of Energy Office of Science, and involved collaboration with researchers from the Air Force Research Laboratory (AFRL), supported by the Air Force Office of Scientific Research. Beyond allowing fabrication of disappearing circuits, the technology could be used as a form of timed release in which the dissipation of the carbon patterns could control other processes, such as the release of biomolecules.\u003C\/p\u003E\u003Cp\u003E\u201cWe will now be able to draw electronic circuits that evolve over time,\u201d said \u003Ca href=\u0022http:\/\/www.me.gatech.edu\/faculty\/fedorov\u0022\u003EAndrei Fedorov\u003C\/a\u003E, a professor in the \u003Ca href=\u0022http:\/\/www.me.gatech.edu\/\u0022\u003EGeorge W. Woodruff School of Mechanical Engineering\u003C\/a\u003E at Georgia Tech. \u201cYou could design a circuit that operates one way now, but after waiting a day for the carbon to diffuse over the graphene surface, you would no longer have an electronic device. Today the device would do one thing; tomorrow it would do something entirely different.\u201d\u003C\/p\u003E\u003Cp\u003EThe project began as a way to clean up hydrocarbons contaminating the surface of the graphene. But the researchers soon realized they could use it to create patterns, utilizing the amorphous carbon produced via electron beam \u201cwriting\u201d as a dopant to create negatively-charged sections of graphene.\u003C\/p\u003E\u003Cp\u003EThe researchers were initially perplexed to discover that their newly-formed patterns disappeared over time. They used electronic measurements and atomic force microscopy to confirm that the carbon patterns had moved on the graphene surface to ultimately form a uniform coverage over an entire graphene surface. The change usually occurs over tens of hours, and ultimately converts positively-charged (p-doped) surface regions to surfaces with a uniformly negative charge (n-doped) while forming an intermediate p-n junction domain in the course of this evolution.\u003C\/p\u003E\u003Cp\u003E\u201cThe electronic structures continuously change over time,\u201d Fedorov explained. \u201cThat gives you a reconfigurable device, especially since our carbon deposition is done not using bulk films, but rather an electron beam that is used to draw where you want a negatively-doped domain to exist.\u201d\u003C\/p\u003E\u003Cp\u003EGraphene consists of carbon atoms arranged in a tight lattice. The unique structure provides attractive electronic properties that have led to widespread study of graphene as a potential new material for advanced electronics applications.\u003C\/p\u003E\u003Cp\u003EBut graphene still consists of carbon atoms, and when patterns are deposited on the surface with ordinary carbon atoms, they begin slowly migrating over the graphene surface. The speed at which the atoms move around can be adjusted by varying the temperature or by fabricating structures that direct the movement of the atoms. The carbon atoms can also be \u201cfrozen\u201d into a fixed pattern by using a laser to convert them to graphite \u2013 another form of carbon.\u003C\/p\u003E\u003Cp\u003E\u201cThere are multiple ways to modulate the dynamic state, through changing the temperature because that controls the diffusion rate of carbon, by directing the atomic flow, or by changing the carbon phase,\u201d Fedorov said. \u201cThe carbon deposited through the focused electron beam induced deposition (FEBID) process is linked to graphene very loosely through van der Waals interactions, so it is mobile.\u201d\u003C\/p\u003E\u003Cp\u003EBeyond the potential security applications for disappearing circuits, Fedorov sees the possibility of simplified control mechanisms that would use the diffusing patterns to turn processes off at preset intervals. The technique might also be used to time the release of pharmaceuticals or other biomedical processes.\u003C\/p\u003E\u003Cp\u003E\u201cYou could write information in ones and zeroes with the electron beam, use the device to transfer information, and then two hours later the information will have disappeared,\u201d he said. \u201cInstead of relying on complex control algorithms that a microprocessor has to execute, by changing the dynamic state or the electronic system itself, your program could become very simple. Perhaps there could be certain activated, triggered processes that could benefit from this type of behavior in which the electronic state changes continuously over time.\u201d\u003C\/p\u003E\u003Cp\u003EFedorov and his collaborators have so far shown only the ability to create simple patterns of charged domains in the graphene. Their next step will be to use their p-n junctions to create devices that would operate for specific periods of time.\u003C\/p\u003E\u003Cp\u003EFedorov admits that this dynamic carbon patterning could pose a challenge for electrical engineers accustomed to static devices that perform the same functions day after day. But he thinks that some will find useful applications for this new phenomena.\u003C\/p\u003E\u003Cp\u003E\u201cWe have made a critical step in discovery and understanding,\u201d he said. \u201cThe next step will be to demonstrate a complicated and unique application which would otherwise be impossible to do with a conventional circuit. That would bring a whole new level of excitement to this.\u201d\u003C\/p\u003E\u003Cp\u003ESongkil Kim, a post-doctoral fellow in Fedorov group, was a lead researcher in this work assisted by Georgia Tech\u2019s graduate students M. Russell and M. Henry. Other collaborators on the project include S. S. Kim, R. R. Naik, and A. A. Voevodin from the U.S. Air Force Research Laboratory and S. S. Jang, and V. V. Tsukruk from the School of Materials Science and Engineering at Georgia Tech.\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis research was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under Award DE-SC0010729 and by the Air Force Office of Scientific Research (AFOSR) through BIONIC Center Award FA9550-09-1-0162. The comments and conclusions are those of the authors and do not necessarily reflect the official views of the DOE or AFOSR.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECITATION\u003C\/strong\u003E: S. Kim, et al., \u201cDynamic modulation of electronic properties of graphene by localized carbon doping using focused electron beam induced deposition,\u201d (Nanoscale 7, 14946-14952, 2015). \u003Ca href=\u0022http:\/\/dx.doi.org\/10.1039\/c5nr04063a\u0022\u003Ehttp:\/\/dx.doi.org\/10.1039\/c5nr04063a\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E177 North Avenue\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia 30332-0181 USA\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contact\u003C\/strong\u003E: John Toon (404-894-6986) (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E).\u003Cbr \/\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EUsing carbon atoms deposited on graphene with a focused electron beam process, researchers have demonstrated a technique for creating dynamic patterns on graphene surfaces. The patterns could be used to make reconfigurable electronic circuits.\u0026nbsp;\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have demonstrated a technique for creating dynamic patterns on graphene surfaces."}],"uid":"27303","created_gmt":"2015-09-29 10:50:53","changed_gmt":"2016-10-08 03:19:40","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2015-09-29T00:00:00-04:00","iso_date":"2015-09-29T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"453351":{"id":"453351","type":"image","title":"Electron beam writing","body":null,"created":"1449256297","gmt_created":"2015-12-04 19:11:37","changed":"1475895197","gmt_changed":"2016-10-08 02:53:17","alt":"Electron beam writing","file":{"fid":"203411","name":"electron-beam-writing.jpg","image_path":"\/sites\/default\/files\/images\/electron-beam-writing.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/electron-beam-writing.jpg","mime":"image\/jpeg","size":87461,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/electron-beam-writing.jpg?itok=njehdxtp"}},"453361":{"id":"453361","type":"image","title":"Graphene surface","body":null,"created":"1449256297","gmt_created":"2015-12-04 19:11:37","changed":"1475895197","gmt_changed":"2016-10-08 02:53:17","alt":"Graphene surface","file":{"fid":"203412","name":"graphene-surface2.jpg","image_path":"\/sites\/default\/files\/images\/graphene-surface2_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-surface2_0.jpg","mime":"image\/jpeg","size":93659,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-surface2_0.jpg?itok=hztMts22"}},"453371":{"id":"453371","type":"image","title":"Graphene doping with carbon","body":null,"created":"1449256297","gmt_created":"2015-12-04 19:11:37","changed":"1475895197","gmt_changed":"2016-10-08 02:53:17","alt":"Graphene doping with carbon","file":{"fid":"203413","name":"graphene-doping.jpg","image_path":"\/sites\/default\/files\/images\/graphene-doping_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-doping_0.jpg","mime":"image\/jpeg","size":410756,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-doping_0.jpg?itok=YulTaY9E"}}},"media_ids":["453351","453361","453371"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"}],"keywords":[{"id":"2781","name":"Andrei Fedorov"},{"id":"610","name":"carbon"},{"id":"8458","name":"doping"},{"id":"143131","name":"focused electron beam"},{"id":"429","name":"graphene"},{"id":"52411","name":"p-n junction"}],"core_research_areas":[{"id":"39451","name":"Electronics and Nanotechnology"},{"id":"39471","name":"Materials"}],"news_room_topics":[{"id":"71881","name":"Science and Technology"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E(404) 894-6986\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"293851":{"#nid":"293851","#data":{"type":"news","title":"As Strong as its Weakest Link: Experiments Determine Real-world Limits of Graphene","body":[{"value":"\u003Cp\u003EThere is no disputing graphene is strong. But new research by Rice University and the Georgia Institute of Technology should prompt manufacturers to look a little deeper as they consider the miracle material for applications.\u003C\/p\u003E\u003Cp\u003EThe atom-thin sheet of carbon is touted not just for its electrical properties but also for its physical strength and flexibility. The bonds between carbon atoms are well known as the strongest in nature, so a perfect sheet of graphene should withstand just about anything. Reinforcing composite materials is among the material\u2019s potential applications.\u003C\/p\u003E\u003Cp\u003EBut materials scientists know perfection is hard to achieve. Researchers Jun Lou at Rice and \u003Ca href=\u0022https:\/\/www.me.gatech.edu\/faculty\/t_zhu\u0022\u003ETing Zhu\u003C\/a\u003E at Georgia Tech have measured the fracture toughness of imperfect graphene for the first time and found it to be somewhat brittle. While it\u0027s still very useful, graphene is really only as strong as its weakest link, which they determined to be \u0022substantially lower\u0022 than the intrinsic strength of graphene.\u003C\/p\u003E\u003Cp\u003E\u201cGraphene has exceptional physical properties, but to use it in real applications, we have to understand the useful strength of large-area graphene, which is controlled by the fracture toughness,\u201d said Zhu, who is an associate professor in the \u003Ca href=\u0022http:\/\/www.me.gatech.edu\/\u0022\u003EWoodruff School of Mechanical Engineering\u003C\/a\u003E at Georgia Tech.\u003C\/p\u003E\u003Cp\u003EThe researchers reported in the journal \u003Cem\u003ENature Communications\u003C\/em\u003E the results of tests in which they physically pulled graphene apart to see how much force it would take. Specifically, they wanted to see if graphene follows the century-old Griffith theory that quantifies the useful strength of brittle materials.\u003C\/p\u003E\u003Cp\u003EIt does, said Lou. \u0022Remarkably, in this case, thermodynamic energy still rules,\u0022 he said.\u003C\/p\u003E\u003Cp\u003EImperfections in graphene drastically lessen its strength \u2013 with an upper limit of about 100 gigapascals (GPa) for perfect graphene previously measured by nanoindentation \u2013 according to physical testing at Rice and molecular dynamics simulations at Georgia Tech. That\u0027s important for engineers to understand as they think about using graphene for flexible electronics, composite material and other applications in which stresses on microscopic flaws could lead to failure.\u003C\/p\u003E\u003Cp\u003EThe Griffith criterion developed by a British engineer during World War I describes the relationship between the size of a crack in a material and the force required to make that crack grow. Ultimately, A.A. Griffith hoped to understand why brittle materials fail.\u003C\/p\u003E\u003Cp\u003EGraphene, it turns out, is no different from the glass fibers Griffith tested.\u003C\/p\u003E\u003Cp\u003E\u0022Everybody thinks the carbon-carbon bond is the strongest bond in nature, so the material must be very good,\u0022 Lou said. \u0022But that\u0027s not true anymore, once you have those defects. The larger the sheet, the higher the probability of defects. That\u0027s well known in the ceramic community.\u0022\u003C\/p\u003E\u003Cp\u003EA defect can be as small as an atom missing from the hexagonal lattice of graphene. But for a real-world test, the researchers had to make a defect of their own \u2013 a pre-crack \u2013 they could actually see. \u0022We know there will be pinholes and other defects in graphene,\u0022 he said. \u0022The pre-crack overshadows those defects to become the weakest spot \u2013 so I know exactly where the fracture will happen when we pull it.\u003C\/p\u003E\u003Cp\u003E\u0022The material resistance to the crack growth \u2013 the fracture toughness \u2013 is what we\u0027re measuring here, and that\u0027s a very important engineering property,\u0022 he said.\u003C\/p\u003E\u003Cp\u003EJust setting up the experiment required several years of work to overcome technical difficulties, Lou said. To suspend it on a tiny cantilever spring stage similar to an atomic force microscopy (AFM) probe, a graphene sheet had to be clean and dry so it would adhere (via van der Waals force) to the stage without compromising the stage movement necessary for the testing. Once mounted, the researchers used a focused ion beam to cut a pre-crack less than 10 percent of the width into the microns-wide section of suspended graphene. Then they pulled the graphene in half, measuring the force required.\u003C\/p\u003E\u003Cp\u003EWhile the Rice team was working on the experiment, Zhu and his team performed computer simulations to understand the entire fracture process.\u003C\/p\u003E\u003Cp\u003E\u201cWe can directly simulate the whole deformation process by tracking the motion and displacement with atomic-scale resolution in fairly large samples so our results can be directly correlated with the experiment,\u201d said Zhu. \u201cThe modeling is tightly coupled with the experiments.\u201d\u003C\/p\u003E\u003Cp\u003EThe combination of modeling and experiment provides a level of detail that allowed the researchers to better understand the fracture process \u2013 and the tradeoff between toughness and strength in the graphene. What the scientists have learned in the research points out the importance of fabricating high quality graphene sheets without defects \u2013 which could set the stage for fracture.\u003C\/p\u003E\u003Cp\u003E\u201cUnderstanding the tradeoff between strength and toughness provides important insights for the future utilization of graphene in structural and functional applications,\u201d Zhu added. \u201cThis research provides a foundational framework for further study of the mechanical properties of graphene.\u201d\u003C\/p\u003E\u003Cp\u003ELou said the techniques they used should work for any two-dimensional material. \u0022It\u0027s important to understand how defects will affect the handling, processing and manufacture of these materials,\u0022 he said. \u0022Our work should open up new directions for testing the mechanical properties of 2-D materials.\u0022\u003C\/p\u003E\u003Cp\u003ECo-authors of the paper are graduate students Peng Zhang, Lulu Ma, Phillip Loya and Yongji Gong, and former graduate students Cheng Peng and Jiangnan Zhang, all at Rice; Feifei Fan and Zhi Zeng, graduate students at Georgia Tech; Zheng Liu, an assistant professor at Nanyang Technological University, Singapore, with a complimentary appointment at Rice; Pulickel Ajayan, Rice\u0027s Benjamin M. and Mary Greenwood Anderson Professor in Materials Science and Nanoengineering and of Chemistry; and Xingxiang Zhang, a professor at Tianjin Polytechnic University, China.\u003C\/p\u003E\u003Cp\u003ELou is an associate professor of Materials Science and Nanoengineering and of Chemistry at Rice. The Welch Foundation, the National Science Foundation, the U.S. Office of Naval Research and the Korean Institute of Machinery and Materials supported the research. \u003Cbr \/\u003E\u003Cbr \/\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003E177 North Avenue\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EAtlanta, Georgia\u0026nbsp; 30332-0181\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EGeorgia Tech Contacts: John Toon (404-894-6986) (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Brett Israel (404-385-1933) (\u003Ca href=\u0022mailto:brett.israel@comm.gatech.edu\u0022\u003Ebrett.israel@comm.gatech.edu\u003C\/a\u003E).\u003C\/p\u003E\u003Cp\u003ERice Contacts: David Ruth (713-348-6327) (\u003Ca href=\u0022mailto:david@rice.edu\u0022\u003Edavid@rice.edu\u003C\/a\u003E) or Mike Williams (713-348-6728)\u003Cbr \/\u003E(\u003Ca href=\u0022mailto:mikewilliams@rice.edu\u0022\u003Emikewilliams@rice.edu\u003C\/a\u003E).\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cbr \/\u003E\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EResearchers have measured the fracture toughness of imperfect graphene for the first time and found it to be somewhat brittle. While it\u0027s still very useful, graphene is really only as strong as its weakest link, which they determined to be \u0022substantially lower\u0022 than the intrinsic strength of graphene.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have measured the fracture toughness of imperfect graphene for the first time and found it to be somewhat brittle."}],"uid":"27303","created_gmt":"2014-04-29 09:37:53","changed_gmt":"2016-10-08 03:16:18","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2014-04-29T00:00:00-04:00","iso_date":"2014-04-29T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"293781":{"id":"293781","type":"image","title":"Graphene Fracture","body":null,"created":"1449244313","gmt_created":"2015-12-04 15:51:53","changed":"1475894991","gmt_changed":"2016-10-08 02:49:51","alt":"Graphene Fracture","file":{"fid":"199314","name":"ting-zhu218.jpg","image_path":"\/sites\/default\/files\/images\/ting-zhu218_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/ting-zhu218_0.jpg","mime":"image\/jpeg","size":1183429,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/ting-zhu218_0.jpg?itok=cMbsZfZw"}},"293791":{"id":"293791","type":"image","title":"Fracture-graphene","body":null,"created":"1449244313","gmt_created":"2015-12-04 15:51:53","changed":"1475894991","gmt_changed":"2016-10-08 02:49:51","alt":"Fracture-graphene","file":{"fid":"199315","name":"fractured-graphene.jpg","image_path":"\/sites\/default\/files\/images\/fractured-graphene_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/fractured-graphene_0.jpg","mime":"image\/jpeg","size":223579,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/fractured-graphene_0.jpg?itok=4GJ5909g"}},"293801":{"id":"293801","type":"image","title":"Graphene Fracture2","body":null,"created":"1449244313","gmt_created":"2015-12-04 15:51:53","changed":"1475894991","gmt_changed":"2016-10-08 02:49:51","alt":"Graphene Fracture2","file":{"fid":"199316","name":"ting-zhu83.jpg","image_path":"\/sites\/default\/files\/images\/ting-zhu83_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/ting-zhu83_0.jpg","mime":"image\/jpeg","size":1169514,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/ting-zhu83_0.jpg?itok=Orjy0q_h"}},"293821":{"id":"293821","type":"image","title":"Fracture-graphene2","body":null,"created":"1449244313","gmt_created":"2015-12-04 15:51:53","changed":"1475894991","gmt_changed":"2016-10-08 02:49:51","alt":"Fracture-graphene2","file":{"fid":"199318","name":"fractured-graphene2.jpg","image_path":"\/sites\/default\/files\/images\/fractured-graphene2_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/fractured-graphene2_0.jpg","mime":"image\/jpeg","size":247133,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/fractured-graphene2_0.jpg?itok=TbkEpjEa"}},"293811":{"id":"293811","type":"image","title":"Graphene Fracture3","body":null,"created":"1449244313","gmt_created":"2015-12-04 15:51:53","changed":"1475894991","gmt_changed":"2016-10-08 02:49:51","alt":"Graphene Fracture3","file":{"fid":"199317","name":"ting-zhu176.jpg","image_path":"\/sites\/default\/files\/images\/ting-zhu176_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/ting-zhu176_0.jpg","mime":"image\/jpeg","size":1384313,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/ting-zhu176_0.jpg?itok=w4QcBWPc"}},"293841":{"id":"293841","type":"image","title":"Rice-graphene","body":null,"created":"1449244331","gmt_created":"2015-12-04 15:52:11","changed":"1475894991","gmt_changed":"2016-10-08 02:49:51","alt":"Rice-graphene","file":{"fid":"199319","name":"rice-graphene.jpg","image_path":"\/sites\/default\/files\/images\/rice-graphene_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/rice-graphene_0.jpg","mime":"image\/jpeg","size":1215211,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/rice-graphene_0.jpg?itok=3AhO_bQw"}}},"media_ids":["293781","293791","293801","293821","293811","293841"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"}],"keywords":[{"id":"92431","name":"fracture"},{"id":"92441","name":"fracture toughness"},{"id":"429","name":"graphene"},{"id":"167377","name":"School of Mechanical Engineering"},{"id":"92451","name":"Ting Zhu"}],"core_research_areas":[{"id":"39451","name":"Electronics and Nanotechnology"},{"id":"39471","name":"Materials"}],"news_room_topics":[{"id":"71881","name":"Science and Technology"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E(404) 894-6986\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"274031":{"#nid":"274031","#data":{"type":"news","title":"Ballistic Transport in Graphene Suggests New Type of Electronic Device","body":[{"value":"\u003Cp\u003EUsing electrons more like photons could provide the foundation for a new type of electronic device that would capitalize on the ability of graphene to carry electrons with almost no resistance even at room temperature \u2013 a property known as ballistic transport.\u003C\/p\u003E\u003Cp\u003EResearch reported this week shows that electrical resistance in nanoribbons of epitaxial graphene changes in discrete steps following quantum mechanical principles. The research shows that the graphene nanoribbons act more like optical waveguides or quantum dots, allowing electrons to flow smoothly along the edges of the material. In ordinary conductors such as copper, resistance increases in proportion to the length as electrons encounter more and more impurities while moving through the conductor.\u003C\/p\u003E\u003Cp\u003EThe ballistic transport properties, similar to those observed in cylindrical carbon nanotubes, exceed theoretical conductance predictions for graphene by a factor of 10. The properties were measured in graphene nanoribbons approximately 40 nanometers wide that had been grown on the edges of three-dimensional structures etched into silicon carbide wafers.\u003C\/p\u003E\u003Cp\u003E\u201cThis work shows that we can control graphene electrons in very different ways because the properties are really exceptional,\u201d said \u003Ca href=\u0022https:\/\/www.physics.gatech.edu\/user\/walter-de-heer\u0022\u003EWalt de Heer\u003C\/a\u003E, a Regent\u2019s professor in the \u003Ca href=\u0022http:\/\/www.physics.gatech.edu\/\u0022\u003ESchool of Physics\u003C\/a\u003E at the Georgia Institute of Technology. \u201cThis could result in a new class of coherent electronic devices based on room temperature ballistic transport in graphene. Such devices would be very different from what we make today in silicon.\u201d\u003C\/p\u003E\u003Cp\u003EThe research, which was supported by the National Science Foundation, the Air Force Office of Scientific Research and the W.M. Keck Foundation, was reported February 5 in the journal \u003Cem\u003ENature\u003C\/em\u003E. The research was done through a collaboration of scientists from Georgia Tech in the United States, Leibniz Universit\u00e4t Hannover in Germany, the Centre National de la Recherche Scientifique (CNRS) in France and Oak Ridge National Laboratory \u2013 supported by the Department of Energy \u2013 in the United States.\u003C\/p\u003E\u003Cp\u003EFor nearly a decade, researchers have been trying to use the unique properties of graphene to create electronic devices that operate much like existing silicon semiconductor chips. But those efforts have met with limited success because graphene \u2013 a lattice of carbon atoms that can be made as little as one layer thick \u2013 cannot be easily given the electronic bandgap that such devices need to operate.\u003C\/p\u003E\u003Cp\u003EDe Heer argues that researchers should stop trying to use graphene like silicon, and instead use its unique electron transport properties to design new types of electronic devices that could allow ultra-fast computing \u2013 based on a new approach to switching. Electrons in the graphene nanoribbons can move tens or hundreds of microns without scattering.\u003C\/p\u003E\u003Cp\u003E\u201cThis constant resistance is related to one of the fundamental constants of physics, the conductance quantum,\u201d de Heer said. \u201cThe resistance of this channel does not depend on temperature, and it does not depend on the amount of current you are putting through it.\u201d\u003C\/p\u003E\u003Cp\u003EWhat does disrupt the flow of electrons, however, is measuring the resistance with an electrical probe. The measurements showed that touching the nanoribbons with a single probe doubles the resistance; touching it with two probes triples the resistance.\u003C\/p\u003E\u003Cp\u003E\u201cThe electrons hit the probe and scatter,\u201d explained de Heer. \u201cIt\u2019s a lot like a stream in which water is flowing nicely until you put rocks in the way. We have done systematic studies to show that when you touch the nanoribbons with a probe, you introduce a method for the electrons to scatter, and that changes the resistance.\u201d\u003C\/p\u003E\u003Cp\u003EThe nanoribbons are grown epitaxially on silicon carbon wafers into which patterns have been etched using standard microelectronics fabrication techniques. When the wafers are heated to approximately 1,000 degrees Celsius, silicon is preferentially driven off along the edges, forming graphene nanoribbons whose structure is determined by the pattern of the three-dimensional surface. Once grown, the nanoribbons require no further processing.\u003C\/p\u003E\u003Cp\u003EThe advantage of fabricating graphene nanoribbons this way is that it produces edges that are perfectly smooth, annealed by the fabrication process. The smooth edges allow electrons to flow through the nanoribbons without disruption. If traditional etching techniques are used to cut nanoribbons from graphene sheets, the resulting edges are too rough to allow ballistic transport.\u003C\/p\u003E\u003Cp\u003E\u201cIt seems that the current is primarily flowing on the edges,\u201d de Heer said. \u201cThere are other electrons in the bulk portion of the nanoribbons, but they do not interact with the electrons flowing at the edges.\u201d\u003C\/p\u003E\u003Cp\u003EThe electrons on the edge flow more like photons in optical fiber, helping them avoid scattering. \u201cThese electrons are really behaving more like light,\u201d he said. \u201cIt is like light going through an optical fiber. Because of the way the fiber is made, the light transmits without scattering.\u201d\u003C\/p\u003E\u003Cp\u003EThe researchers measured ballistic conductance in the graphene nanoribbons for up to 16 microns. Electron mobility measurements surpassing one million correspond to a sheet resistance of one ohm per square that is two orders of magnitude lower than what is observed in two-dimensional graphene \u2013 and ten times smaller than the best theoretical predictions for graphene.\u003C\/p\u003E\u003Cp\u003E\u201cThis should enable a new way of doing electronics,\u201d de Heer said. \u201cWe are already able to steer these electrons and we can switch them using rudimentary means. We can put a roadblock, and then open it up again. New kinds of switches for this material are now on the horizon.\u201d\u003C\/p\u003E\u003Cp\u003ETheoretical explanations for what the researchers have measured are incomplete. De Heer speculates that the graphene nanoribbons may be producing a new type of electronic transport similar to what is observed in superconductors. \u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u201cThere is a lot of fundamental physics that needs to be done to understand what we are seeing,\u201d he added. \u201cWe believe this shows that there is a real possibility for a new type of graphene-based electronics.\u201d\u003C\/p\u003E\u003Cp\u003EGeorgia Tech researchers have pioneered graphene-based electronics since 2001, for which they hold a patent, filed in 2003. The technique involves etching patterns into electronics-grade silicon carbide wafers, then heating the wafers to drive off silicon, leaving patterns of graphene.\u003C\/p\u003E\u003Cp\u003EIn addition to de Heer, the paper\u2019s authors included Jens Baringhaus, Frederik Edler and Christoph Tegenkamp from the Institut f\u00fcr Festk\u00f6rperphysik, Leibniz Universit\u00e4t, Hannover in Germany; Edward Conrad, Ming Ruan and Zhigang Jiang from the School of Physics at Georgia Tech; Claire Berger from Georgia Tech and Institut N\u00e9el at the Centre National de la Recherche Scientifique (CNRS) in France; Antonio Tejeda and Muriel Sicot from the Institut Jean Lamour, Universite de Nancy, Centre National de la Recherche Scientifique (CNRS) in France; An-Ping Li from the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory, and Amina Taleb-Ibrahimi from the CNRS Synchotron SOLEIL in France.\u003C\/p\u003E\u003Cp\u003EThis research was supported by the National Science Foundation (NSF) Materials Research Science and Engineering Center (MRSEC) at Georgia Tech through award DMR-0820382; the Air Force Office of Scientific Research (AFOSR); the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy, and the Partner University Fund from the Embassy of France. Any conclusions or recommendations are those of the authors and do not necessarily represent the official views of the NSF, DOE or AFOSR.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECITATION\u003C\/strong\u003E: Jens Baringhaus, et al., \u201cExceptional ballistic transport in epitaxial graphene nanoribbons,\u201d (Nature 2013). (\u003Ca href=\u0022http:\/\/dx.doi.org\/10.1038\/nature12952\u0022\u003Ehttp:\/\/dx.doi.org\/10.1038\/nature12952\u003C\/a\u003E).\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EResearch News\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E177 North Avenue\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia\u0026nbsp; 30332-0181\u0026nbsp; USA\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986) (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Brett Israel (404-385-1933) (\u003Ca href=\u0022mailto:brett.israel@comm.gatech.edu\u0022\u003Ebrett.israel@comm.gatech.edu\u003C\/a\u003E).\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003Cbr \/\u003E\u003Cbr \/\u003E\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EUsing electrons more like photons could provide the foundation for a new type of electronic device that would capitalize on the ability of graphene to carry electrons with almost no resistance even at room temperature \u2013 a property known as ballistic transport.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Using electrons more like photons could provide the foundation for a new type of electronic device that would capitalize on the ability of graphene to carry electrons with almost no resistance."}],"uid":"27303","created_gmt":"2014-02-05 11:38:02","changed_gmt":"2016-10-08 03:15:51","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2014-02-05T00:00:00-05:00","iso_date":"2014-02-05T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"274011":{"id":"274011","type":"image","title":"Ballistic Transport in Graphene Nanoribbons","body":null,"created":"1449244112","gmt_created":"2015-12-04 15:48:32","changed":"1475894964","gmt_changed":"2016-10-08 02:49:24","alt":"Ballistic Transport in Graphene Nanoribbons","file":{"fid":"198711","name":"graphene-nanoribbons.jpg","image_path":"\/sites\/default\/files\/images\/graphene-nanoribbons_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-nanoribbons_0.jpg","mime":"image\/jpeg","size":1120437,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-nanoribbons_0.jpg?itok=-qqd5pwt"}},"274001":{"id":"274001","type":"image","title":"Walt de Heer - Ballistic Transport","body":null,"created":"1449244112","gmt_created":"2015-12-04 15:48:32","changed":"1475894964","gmt_changed":"2016-10-08 02:49:24","alt":"Walt de Heer - Ballistic Transport","file":{"fid":"198710","name":"walt-de-heer.jpg","image_path":"\/sites\/default\/files\/images\/walt-de-heer_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/walt-de-heer_0.jpg","mime":"image\/jpeg","size":947684,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/walt-de-heer_0.jpg?itok=IEGnB69-"}}},"media_ids":["274011","274001"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"85841","name":"ballistic transport"},{"id":"9116","name":"epitaxial graphene"},{"id":"429","name":"graphene"},{"id":"12423","name":"nanoribbons"},{"id":"166937","name":"School of Physics"},{"id":"12422","name":"Walt de Heer"}],"core_research_areas":[{"id":"39451","name":"Electronics and Nanotechnology"},{"id":"39471","name":"Materials"}],"news_room_topics":[{"id":"71881","name":"Science and Technology"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E(404) 894-6986\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"260521":{"#nid":"260521","#data":{"type":"news","title":"Graphene-Based Nano-Antennas May Enable Networks of Tiny Machines","body":[{"value":"\u003Cp\u003ENetworks of nanometer-scale machines offer exciting potential applications in medicine, industry, environmental protection and defense, but until now there\u2019s been one very small problem: the limited capability of nanoscale antennas fabricated from traditional metallic components.\u003C\/p\u003E\u003Cp\u003EWith antennas made from conventional materials like copper, communication between low-power nanomachines would be virtually impossible. But by taking advantage of the unique electronic properties of the material known as graphene, researchers now believe they\u2019re on track to connect devices powered by small amounts of scavenged energy.\u003C\/p\u003E\u003Cp\u003EBased on a honeycomb network of carbon atoms, graphene could generate a type of electronic surface wave that would allow antennas just one micron long and 10 to 100 nanometers wide to do the work of much larger antennas. While operating graphene nano-antennas have yet to be demonstrated, the researchers say their modeling and simulations show that nano-networks using the new approach are feasible with the alternative material.\u003C\/p\u003E\u003Cp\u003E\u201cWe are exploiting the peculiar propagation of electrons in graphene to make a very small antenna that can radiate at much lower frequencies than classical metallic antennas of the same size,\u201d said \u003Ca href=\u0022http:\/\/www.ece.gatech.edu\/faculty-staff\/fac_profiles\/bio.php?id=3\u0022\u003EIan Akyildiz\u003C\/a\u003E, a Ken Byers Chair professor in Telecommunications in the \u003Ca href=\u0022http:\/\/www.ece.gatech.edu\/\u0022\u003ESchool of Electrical and Computer Engineering\u003C\/a\u003E at the Georgia Institute of Technology. \u201cWe believe that this is just the beginning of a new networking and communications paradigm based on the use of graphene.\u201d\u003C\/p\u003E\u003Cp\u003ESponsored by the National Science Foundation, the research is scheduled to be reported in the journal \u003Cem\u003EIEEE Journal of Selected Areas in Communications\u003C\/em\u003E (IEEE JSAC). In addition to the nanoscale antennas, the researchers are also working on graphene-based nanoscale transceivers and the transmission protocols that would be necessary for communication between nanomachines.\u003C\/p\u003E\u003Cp\u003EThe communications challenge is that at the micron scale, metallic antennas would have to operate at frequencies of hundreds of terahertz. While those frequencies might offer advantages in communication speed, their range would be limited by propagation losses to just a few micrometers. And they\u2019d require lots of power \u2013 more power than nanomachines are likely to have.\u003C\/p\u003E\u003Cp\u003EAkyildiz has studied nanonetworks since the late 1990s, and had concluded that traditional electromagnetic communication between these machines might not be possible. But then he and his Ph.D. student, Josep Jornet \u2013 who graduated in August 2013 and is now an assistant professor at the State University of New York at Buffalo \u2013 began reading about the amazing properties of graphene. They were especially interested in how electrons behave in single-layer sheets of the material.\u003C\/p\u003E\u003Cp\u003E\u201cWhen electrons in graphene are excited by an incoming electromagnetic wave, for instance, they start moving back and forth,\u201d explained Akyildiz. \u201cBecause of the unique properties of the graphene, this global oscillation of electrical charge results in a confined electromagnetic wave on top of the graphene layer.\u201d\u003C\/p\u003E\u003Cp\u003EKnown technically as a surface plasmon polariton (SPP) wave, the effect will allow the nano-antennas to operate at the low end of the terahertz frequency range, between 0.1 and 10 terahertz \u2013 instead of at 150 terahertz required by traditional copper antennas at nanoscale sizes. For transmitting, the SPP waves can be created by injecting electrons into the dielectric layer beneath the graphene sheet.\u003C\/p\u003E\u003Cp\u003EMaterials such as gold, silver and other noble metals also can support the propagation of SPP waves, but only at much higher frequencies than graphene. Conventional materials such as copper don\u2019t support the waves.\u003C\/p\u003E\u003Cp\u003EBy allowing electromagnetic propagation at lower terahertz frequencies, the SPP waves require less power \u2013 putting them within range of what might be feasible for nanomachines operated by energy harvesting technology pioneered by Zhong Lin Wang, a professor in Georgia Tech\u2019s School of Materials Science and Engineering.\u003C\/p\u003E\u003Cp\u003E\u201cWith this antenna, we can cut the frequency by two orders of magnitude and cut the power needs by four orders of magnitude,\u201d said Jornet. \u201cUsing this antenna, we believe the energy-harvesting techniques developed by Dr. Wang would give us enough power to create a communications link between nanomachines.\u201d\u003C\/p\u003E\u003Cp\u003EThe nanomachines in the network that Akyildiz and Jornet envision would include several integrated components. In addition to the energy-harvesting nanogenerators, there would be nanoscale sensing, processing and memory, technologies that are under development by other groups. The nanoscale antenna and transceiver work being done at Georgia Tech would allow the devices to communicate the information they sense and process to the outside world.\u003C\/p\u003E\u003Cp\u003E\u201cEach one of these components would have a nanoscale measurement, but in total we would have a machine measuring a few micrometers,\u201d said Jornet. \u201cThere would be lots of tradeoffs in energy use and size.\u201d\u003C\/p\u003E\u003Cp\u003EBeyond giving nanomachines the ability to communicate, hundreds or thousands of graphene antenna-transceiver sets might be combined to help full-size cellular phones and Internet-connected laptops communicate faster.\u003C\/p\u003E\u003Cp\u003E\u201cThe terahertz band can boost current data rates in wireless networks by more than two orders of magnitude,\u201d Akyildiz noted. \u201cThe data rates in current cellular systems are up to one gigabit-per-second in LTE advanced networks or 10 gigabits-per-second in the so-called millimeter wave or 60 gigahertz systems. We expect data rates on the order of terabits-per-second in the terahertz band.\u201d\u003C\/p\u003E\u003Cp\u003EThe unique properties of graphene, Akyildiz says, are critical to this antenna \u2013 and other future electronic devices. \u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u201cGraphene is a very powerful nanomaterial that will dominate our lives in the next half-century,\u201d he said. \u201cThe European community will be supporting a very large consortium involving many universities and companies with an investment of one billion euros to conduct research into this material.\u201d\u003C\/p\u003E\u003Cp\u003EThe researchers have so far evaluated numerous nano-antenna designs using modeling and simulation techniques in their laboratory. The next step will be to actually fabricate a graphene nano-antenna and operate it using a transceiver also based on graphene.\u003C\/p\u003E\u003Cp\u003E\u201cOur project shows that the concept of graphene-based nano-antennas is feasible, especially when taking into account very accurate models of electron transport in graphene,\u201d said Akyildiz. \u201cMany challenges remain open, but this is a first step toward creating advanced nanomachines with many applications in the biomedical, environmental, industrial and military fields.\u201d\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThe research described here was supported by the National Science Foundation under award number CCF-1349828. Any opinions or conclusions are those of the authors and do not necessarily reflect the official views of the NSF.\u003C\/em\u003E\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EResearch News\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E177 North Avenue\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia\u0026nbsp; 30332-0181\u0026nbsp; USA\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) (404-894-6986) or Brett Israel (\u003Ca href=\u0022mailto:brett.israel@comm.gatech.edu\u0022\u003Ebrett.israel@comm.gatech.edu\u003C\/a\u003E) (404-385-1933).\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EResearchers are taking advantage of the unique properties of graphene to design tiny antennas that may open the possibility for networks of nanometer-scale machines.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Graphene antennas may open the possibility for networks of nanometer-scale machines."}],"uid":"27303","created_gmt":"2013-12-11 23:58:05","changed_gmt":"2016-10-08 03:15:33","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2013-12-11T00:00:00-05:00","iso_date":"2013-12-11T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"260501":{"id":"260501","type":"image","title":"Graphene antenna","body":null,"created":"1449243987","gmt_created":"2015-12-04 15:46:27","changed":"1475894945","gmt_changed":"2016-10-08 02:49:05","alt":"Graphene antenna","file":{"fid":"198347","name":"graphene-antenna-akyildiz.jpg","image_path":"\/sites\/default\/files\/images\/graphene-antenna-akyildiz_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-antenna-akyildiz_0.jpg","mime":"image\/jpeg","size":1017137,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-antenna-akyildiz_0.jpg?itok=ALHyMmmc"}},"260511":{"id":"260511","type":"image","title":"Graphene antenna schematic","body":null,"created":"1449243987","gmt_created":"2015-12-04 15:46:27","changed":"1475894945","gmt_changed":"2016-10-08 02:49:05","alt":"Graphene antenna schematic","file":{"fid":"198348","name":"graphene-antenna-schematic.jpg","image_path":"\/sites\/default\/files\/images\/graphene-antenna-schematic_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-antenna-schematic_0.jpg","mime":"image\/jpeg","size":590277,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-antenna-schematic_0.jpg?itok=8cw_N5YE"}}},"media_ids":["260501","260511"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"144","name":"Energy"},{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"}],"keywords":[{"id":"2616","name":"antenna"},{"id":"429","name":"graphene"},{"id":"12058","name":"Ian Akyildiz"},{"id":"82051","name":"nanomachine"},{"id":"168023","name":"School of Electrica and Computer Engineering"}],"core_research_areas":[{"id":"39451","name":"Electronics and Nanotechnology"},{"id":"39471","name":"Materials"},{"id":"39481","name":"National Security"},{"id":"39541","name":"Systems"}],"news_room_topics":[{"id":"71881","name":"Science and Technology"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E(404) 894-6986\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"255281":{"#nid":"255281","#data":{"type":"news","title":"Local tuning of graphene thickness on 4H-SiC C-face using decomposing silicon nitride masks","body":[{"value":"\u003Cp\u003EAuthors:\u0026nbsp; \u003Ca href=\u0022http:\/\/arxiv.org\/find\/cond-mat\/1\/au:+Puybaret_R\/0\/1\/0\/all\/0\/1\u0022 rel=\u0022nofollow\u0022\u003ERenaud Puybaret\u003C\/a\u003E, \u003Ca href=\u0022http:\/\/arxiv.org\/find\/cond-mat\/1\/au:+Hankinson_J\/0\/1\/0\/all\/0\/1\u0022 rel=\u0022nofollow\u0022\u003EJohn Hankinson\u003C\/a\u003E, \u003Ca href=\u0022http:\/\/arxiv.org\/find\/cond-mat\/1\/au:+Ougazzaden_A\/0\/1\/0\/all\/0\/1\u0022 rel=\u0022nofollow\u0022\u003EAbdallah Ougazzaden\u003C\/a\u003E, \u003Ca href=\u0022http:\/\/arxiv.org\/find\/cond-mat\/1\/au:+Voss_P\/0\/1\/0\/all\/0\/1\u0022 rel=\u0022nofollow\u0022\u003EPaul L Voss\u003C\/a\u003E, \u003Ca href=\u0022http:\/\/arxiv.org\/find\/cond-mat\/1\/au:+Berger_C\/0\/1\/0\/all\/0\/1\u0022 rel=\u0022nofollow\u0022\u003EClaire Berger\u003C\/a\u003E, \u003Ca href=\u0022http:\/\/arxiv.org\/find\/cond-mat\/1\/au:+Heer_W\/0\/1\/0\/all\/0\/1\u0022 rel=\u0022nofollow\u0022\u003EWalt A de Heer\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003EPatterning of graphene is key for device fabrication. We report a way to increase or reduce the number of layers in epitaxial graphene grown on the C-face (000-1) of silicon carbide by the deposition of a 120 nm to 150nm-thick silicon nitride mask prior to graphitization. In our process we find that areas covered by a Si-rich SiN mask have three more layers than non-masked areas. Conversely N-rich SiN decreases the thickness by three layers. In both cases the mask decomposes before graphitization is completed. Graphene grown in masked areas show good quality as observed by Raman, AFM and transport data. By tailoring the growth parameters selective graphene growth has been obtained.\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EPatterning of graphene is key for device fabrication. We report a way to increase or reduce the number of layers in epitaxial graphene grown on the C-face (000-1) of silicon carbide by the deposition of a 120 nm to 150nm-thick silicon nitride mask prior to graphitization.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"We report a way to increase or reduce the number of layers in epitaxial graphene grown on the C-face (000-1) of silicon carbide by the deposition of a 120 nm to 150nm-thick silicon nitride mask prior to graphitization."}],"uid":"27428","created_gmt":"2013-11-15 15:23:13","changed_gmt":"2016-10-08 03:15:22","author":"Gina Adams","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2013-07-23T00:00:00-04:00","iso_date":"2013-07-23T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"257351":{"id":"257351","type":"image","title":"Local tuning of graphene thickness on 4H-SiC C-face using decomposing silicon nitride masks","body":null,"created":"1449243856","gmt_created":"2015-12-04 15:44:16","changed":"1475894938","gmt_changed":"2016-10-08 02:48:58","alt":"Local tuning of graphene thickness on 4H-SiC C-face using decomposing silicon nitride masks","file":{"fid":"198252","name":"article5.jpg","image_path":"\/sites\/default\/files\/images\/article5_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/article5_0.jpg","mime":"image\/jpeg","size":54825,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/article5_0.jpg?itok=pffFm8V8"}}},"media_ids":["257351"],"related_links":[{"url":"http:\/\/arxiv.org\/abs\/1307.6197","title":"http:\/\/arxiv.org\/abs\/1307.6197"}],"groups":[{"id":"60783","name":"MRSEC"}],"categories":[{"id":"42941","name":"Art Research"}],"keywords":[{"id":"429","name":"graphene"}],"core_research_areas":[{"id":"39451","name":"Electronics and Nanotechnology"},{"id":"39471","name":"Materials"}],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}},"176051":{"#nid":"176051","#data":{"type":"news","title":"Self-Assembled Monolayers Create P-N Junctions in Graphene Films","body":[{"value":"\u003Cp\u003EThe electronic properties of graphene films are directly affected by the characteristics of the substrates on which they are grown or to which they are transferred. Researchers are taking advantage of this to create graphene p-n junctions by transferring films of the promising electronic material to substrates that have been patterned by compounds that are either strong electron donors or electron acceptors.\u003C\/p\u003E\u003Cp\u003EA low temperature, controllable and stable method has been developed to dope graphene films using self-assembled monolayers (SAM) that modify the interface of graphene and its support substrate. Using this concept, a team of researchers at the Georgia Institute of Technology has created graphene p-n junctions \u2013 which are essential to fabricating devices \u2013 without damaging the material\u2019s lattice structure or significantly reducing electron\/hole mobility.\u003C\/p\u003E\u003Cp\u003EThe graphene was grown on a copper film using chemical vapor deposition (CVD), a process that allows synthesis of large-scale films and their transfer to desired substrates for device applications. The graphene films were transferred to silicon dioxide substrates that were functionalized with the self-assembled monolayers.\u003C\/p\u003E\u003Cp\u003EInformation about creating graphene p-n junctions using self-assembled monolayers was presented on November 28, 2012 at the Fall Meeting of the Materials Research Society. Papers describing aspects of the work were also published in September 2012 in the journals \u003Cem\u003EACS Applied Materials \u0026amp; Interfaces\u003C\/em\u003E and the \u003Cem\u003EJournal of Physical Chemistry C\u003C\/em\u003E. Funding for the research came from the National Science Foundation, through the Georgia Tech Materials Research Science and Engineering Center (MRSEC) and through separate research grants.\u003C\/p\u003E\u003Cp\u003E\u201cWe have been successful at showing that you can make fairly well doped p-type and n-type graphene controllably by patterning the underlying monolayer instead of modifying the graphene directly,\u201d said \u003Ca href=\u0022http:\/\/www.chbe.gatech.edu\/faculty\/henderson\u0022\u003EClifford Henderson\u003C\/a\u003E, a professor in the Georgia Tech \u003Ca href=\u0022http:\/\/www.chbe.gatech.edu\/\u0022\u003ESchool of Chemical \u0026amp; Biomolecular Engineering\u003C\/a\u003E. \u201cPutting graphene on top of self-assembled monolayers uses the effect of electron donation or electron withdrawal from underneath the graphene to modify the material\u2019s electronic properties.\u201d\u003C\/p\u003E\u003Cp\u003EThe Georgia Tech research team working on the project includes faculty members, postdoctoral fellows and graduate students from three different schools. In addition to Henderson, professors who are part of the team include Laren Tolbert from the School of Chemistry and Biochemistry and Samuel Graham from the Woodruff School of Mechanical Engineering.\u0026nbsp; The project team also includes Hossein Sojoudi, a postdoctoral fellow, and Jose Baltazar, a graduate research assistant.\u003C\/p\u003E\u003Cp\u003ECreating n-type and p-type doping in graphene \u2013 which has no natural bandgap \u2013 has led to development of several approaches. Scientists have substituted nitrogen atoms for some of the carbon atoms in the graphene lattice, compounds have been applied to the surface of the graphene, and the edges of graphene nanoribbons have been modified. However, most of these techniques have disadvantages, including disruption of the lattice \u2013 which reduces electron mobility \u2013 and long-term stability issues.\u003C\/p\u003E\u003Cp\u003E\u201cAny time you put graphene into contact with a substrate of any kind, the material has an inherent tendency to change its electrical properties,\u201d Henderson said. \u201cWe wondered if we could do that in a controlled way and use it to our advantage to make the material predominately n-type or p-type. This could create a doping effect without introducing defects that would disrupt the material\u2019s attractive electron mobility.\u201d\u003C\/p\u003E\u003Cp\u003EUsing conventional lithography techniques, the researchers created patterns from different silane materials on a dielectric substrate, usually silicon oxide. The materials were chosen because they are either strong electron donors or electron acceptors. When a thin film of graphene is placed over the patterns, the underlying materials create charged sections in the graphene that correspond to the patterning.\u003C\/p\u003E\u003Cp\u003E\u201cWe were able to dope the graphene into both n-type and p-type materials through an electron donation or withdrawal effect from the monolayer,\u201d Henderson explained. \u201cThat doesn\u2019t lead to the substitutional defects that are seen with many of the other doping processes. The graphene structure itself is still pristine as it comes to us in the transfer process.\u201d\u003C\/p\u003E\u003Cp\u003EThe monolayers are bonded to the dielectric substrate and are thermally stable up to 200 degrees Celsius with the graphene film over them, Sojoudi noted. The Georgia Tech team has used 3-Aminopropyltriethoxysilane (APTES) and perfluorooctyltriethoxysilane (PFES) for patterning. In principle, however, there are many other commercially-available materials that could also create the patterns.\u003C\/p\u003E\u003Cp\u003E\u201cYou can build as many n-type and p-type regions as you want,\u201d Sojoudi said. \u201cYou can even step the doping controllably up and down. This technique gives you control over the doping level and what the dominant carrier is in each region.\u201d\u003C\/p\u003E\u003Cp\u003EThe researchers used their technique to fabricate graphene p-n junctions, which was verified by the creation of field-effect transistors (FET). Characteristic I-V curves indicated the presence of two separate Dirac points, which indicated an energy separation of neutrality points between the p and n regions in the graphene, Sojoudi said.\u003C\/p\u003E\u003Cp\u003EThe group uses chemical vapor deposition to create thin films of graphene on copper foil. A thick film of PMMA was spin-coated atop the graphene, and the underlying copper was then removed. The polymer serves as a carrier for the graphene until it can be placed onto the monolayer-coated substrate, after which it is removed.\u003C\/p\u003E\u003Cp\u003EBeyond developing the doping techniques, the team is also exploring new precursor materials that could allow CVD production of graphene at temperatures low enough to permit fabrication directly on other devices. That could eliminate the need for transferring the graphene from one substrate to another.\u003C\/p\u003E\u003Cp\u003EA low-cost, low-temperature means of producing graphene could also allow the films to find broader applications in displays, solar cells and organic light-emitting diodes, where large sheets of graphene would be needed.\u003C\/p\u003E\u003Cp\u003E\u201cThe real goal is to find ways to make graphene at lower temperatures and in ways that allow us to integrate it with other devices, either silicon CMOS or other materials that couldn\u2019t tolerate the high temperatures required for the initial growth,\u201d Henderson said. \u201cWe are looking at ways to make graphene into a useful electronic or opto-electronic material at low temperatures and in patterned forms.\u201d\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis material is based on work supported by the National Science Foundation (NSF) under Grants CHE-0822697, CHE-0848833 and CMMI-0927736 and the Georgia Tech Materials Research Science and Engineering Center (MRSEC). The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the NSF.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECITATIONS\u003C\/strong\u003E: Sojoudi, Hossein, Creating Graphene p-n Junctions Using Self-Assembled Monolayers, \u003Cem\u003EACS Applied Materials \u0026amp; Interfaces\u003C\/em\u003E, \u003Ca href=\u0022http:\/\/www.dx.doi.org\/10.1021\/am301138v\u0022\u003Edx.doi.org\/10.1021\/am301138v\u003C\/a\u003E and Baltazar, Jose, Facile Formation of Graphene P-N Junctions Using Self-Assembled Monolayers, \u003Cem\u003EThe Journal of Physical Chemistry C\u003C\/em\u003E, \u003Ca href=\u0022http:\/\/www.dx.doi.org\/10.1021\/jp3045737\u0022\u003Edx.doi.org\/10.1021\/jp3045737\u003C\/a\u003E.\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EResearch News\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E177 North Avenue\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia\u0026nbsp; 30332-0181\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EMedia Relations Contact\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E).\u003Cbr \/\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EResearchers are creating graphene p-n junctions by transferring films of the electronic material to substrates that have been patterned by compounds that are either strong electron donors or electron acceptors.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have developed a new way to create graphene p-n junctions."}],"uid":"27303","created_gmt":"2012-12-09 17:14:19","changed_gmt":"2016-10-08 03:13:22","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2012-12-10T00:00:00-05:00","iso_date":"2012-12-10T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"176011":{"id":"176011","type":"image","title":"Self Assembled Monolayers","body":null,"created":"1449179022","gmt_created":"2015-12-03 21:43:42","changed":"1475894819","gmt_changed":"2016-10-08 02:46:59","alt":"Self Assembled Monolayers","file":{"fid":"195861","name":"graphene-monolayer147.jpg","image_path":"\/sites\/default\/files\/images\/graphene-monolayer147_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-monolayer147_0.jpg","mime":"image\/jpeg","size":1937468,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-monolayer147_0.jpg?itok=xS2a3VQ9"}},"176021":{"id":"176021","type":"image","title":"Self Assembled Monolayers2","body":null,"created":"1449179022","gmt_created":"2015-12-03 21:43:42","changed":"1475894819","gmt_changed":"2016-10-08 02:46:59","alt":"Self Assembled Monolayers2","file":{"fid":"195862","name":"graphene-monolayer212.jpg","image_path":"\/sites\/default\/files\/images\/graphene-monolayer212_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-monolayer212_0.jpg","mime":"image\/jpeg","size":1682738,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-monolayer212_0.jpg?itok=DT0PZUmr"}},"176031":{"id":"176031","type":"image","title":"Self Assembled Monolayers3","body":null,"created":"1449179022","gmt_created":"2015-12-03 21:43:42","changed":"1475894819","gmt_changed":"2016-10-08 02:46:59","alt":"Self Assembled Monolayers3","file":{"fid":"195863","name":"graphene-monolayer184.jpg","image_path":"\/sites\/default\/files\/images\/graphene-monolayer184_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-monolayer184_0.jpg","mime":"image\/jpeg","size":1920980,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-monolayer184_0.jpg?itok=wXZLPavV"}},"176041":{"id":"176041","type":"image","title":"Self Assembled Monolayers4","body":null,"created":"1449179022","gmt_created":"2015-12-03 21:43:42","changed":"1475894819","gmt_changed":"2016-10-08 02:46:59","alt":"Self Assembled Monolayers4","file":{"fid":"195864","name":"graphene-monolayers25.jpg","image_path":"\/sites\/default\/files\/images\/graphene-monolayers25_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-monolayers25_0.jpg","mime":"image\/jpeg","size":2457955,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-monolayers25_0.jpg?itok=jqqD_MeF"}}},"media_ids":["176011","176021","176031","176041"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"141","name":"Chemistry and Chemical Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"}],"keywords":[{"id":"52431","name":"Clifford Henderson"},{"id":"429","name":"graphene"},{"id":"52411","name":"p-n junction"},{"id":"167750","name":"School of Chemical \u0026 Biomolecular Engineering"},{"id":"166928","name":"School of Chemistry and Biochemistry"},{"id":"169538","name":"self assembled monolayer"},{"id":"7528","name":"transistors"}],"core_research_areas":[{"id":"39451","name":"Electronics and Nanotechnology"},{"id":"39471","name":"Materials"}],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News\u003C\/p\u003E\u003Cp\u003E(404) 894-6986\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"171751":{"#nid":"171751","#data":{"type":"news","title":"Fabrication on Patterned Silicon Carbide Produces Bandgap for Graphene-Based Electronics","body":[{"value":"\u003Cp\u003EBy fabricating graphene structures atop nanometer-scale \u201csteps\u201d etched into silicon carbide, researchers have for the first time created a substantial electronic bandgap in the material suitable for room-temperature electronics. Use of nanoscale topography to control the properties of graphene could facilitate fabrication of transistors and other devices, potentially opening the door for developing all-carbon integrated circuits.\u003C\/p\u003E\u003Cp\u003EResearchers have measured a bandgap of approximately 0.5 electron-volts in 1.4-nanometer bent sections of graphene nanoribbons. The development could provide new direction to the field of graphene electronics, which has struggled with the challenge of creating bandgap necessary for operation of electronic devices.\u003C\/p\u003E\u003Cp\u003E\u201cThis is a new way of thinking about how to make high-speed graphene electronics,\u201d said Edward Conrad, a professor in the School of Physics at the Georgia Institute of Technology. \u201cWe can now look seriously at making fast transistors from graphene. And because our process is scalable, if we can make one transistor, we can potentially make millions of them.\u201d\u003C\/p\u003E\u003Cp\u003EThe findings were reported November 18 in the journal \u003Cem\u003ENature Physics\u003C\/em\u003E. The research, done at the Georgia Institute of Technology in Atlanta and at SOLEIL, the French national synchrotron facility, has been supported by the National Science Foundation Materials Research Science and Engineering Center (MRSEC) at Georgia Tech, the W.M. Keck Foundation and the Partner University Fund from the Embassy of France.\u003C\/p\u003E\u003Cp\u003EResearchers don\u2019t yet understand why graphene nanoribbons become semiconducting as they bend to enter tiny steps \u2013 about 20 nanometers deep \u2013 that are cut into the silicon carbide wafers. But the researchers believe that strain induced as the carbon lattice bends, along with the confinement of electrons, may be factors creating the bandgap. The nanoribbons are composed of two layers of graphene.\u003C\/p\u003E\u003Cp\u003EProduction of the semiconducting graphene structures begins with the use of e-beams to cut \u201ctrenches\u201d into silicon carbide wafers, which are normally polished to create a flat surface for the growth of epitaxial graphene. Using a high-temperature furnace, tens of thousands of graphene ribbons are then grown across the steps, using photolithography.\u003C\/p\u003E\u003Cp\u003EDuring the growth, the sharp edges of trenches become smoother as the material attempts to regain its flat surface. The growth time must therefore be carefully controlled to prevent the narrow silicon carbide features from melting too much.\u003C\/p\u003E\u003Cp\u003EThe graphene fabrication also must be controlled along a specific direction so that the carbon atom lattice grows into the steps along the material\u2019s \u201carmchair\u201d direction. \u201cIt\u2019s like trying to bend a length of chain-link fence,\u201d Conrad explained. \u201cIt only wants to bend one way.\u201d\u003C\/p\u003E\u003Cp\u003EThe new technique permits not only the creation of a bandgap in the material, but potentially also the fabrication of entire integrated circuits from graphene without the need for interfaces that introduce resistance. On either side of the semiconducting section of the graphene, the nanoribbons retain their metallic properties.\u003C\/p\u003E\u003Cp\u003E\u201cWe can make thousands of these trenches, and we can make them anywhere we want on the wafer,\u201d said Conrad. \u201cThis is more than just semiconducting graphene. The material at the bends is semiconducting, and it\u2019s attached to graphene continuously on both sides. It\u2019s basically a Shottky barrier junction.\u201d\u003C\/p\u003E\u003Cp\u003EBy growing the graphene down one edge of the trench and then up the other side, the researchers could in theory produce two connected Shottky barriers \u2013 a fundamental component of semiconductor devices. Conrad and his colleagues are now working to fabricate transistors based on their discovery.\u003C\/p\u003E\u003Cp\u003EConfirmation of the bandgap came from angle-resolved photoemission spectroscopy measurements made at the Synchrotron CNRS in France. There, the researchers fired powerful photon beams into arrays of the graphene nanoribbons and measured the electrons emitted.\u003C\/p\u003E\u003Cp\u003E\u201cYou can measure the energy of the electrons that come out, and you can measure the direction from which they come out,\u201d said Conrad. \u201cFrom that information, you can work backward to get information about the electronic structure of the nanoribbons.\u201d\u003C\/p\u003E\u003Cp\u003ETheorists had predicted that bending graphene would create a bandgap in the material. But the bandgap measured by the research team was larger than what had been predicted.\u003C\/p\u003E\u003Cp\u003EBeyond building transistors and other devices, in future work the researchers will attempt to learn more about what creates the bandgap \u2013 and how to control it. The property may be controlled by the angle of the bend in the graphene nanoribbon, which can be controlled by altering the depth of the step.\u003C\/p\u003E\u003Cp\u003E\u201cIf you try to lay a carpet over a small imperfection in the floor, the carpet will go over it and you may not even know the imperfection is there,\u201d Conrad explained. \u201cBut if you go over a step, you can tell. There are probably a range of heights in which we can affect the bend.\u201d\u003C\/p\u003E\u003Cp\u003EHe predicts that the discovery will create new activity as other graphene researchers attempt to utilize the results.\u003C\/p\u003E\u003Cp\u003E\u201cIf you can demonstrate a fast device, a lot of people will be interested in this,\u201d Conrad said. \u201cIf this works on a large scale, it could launch a niche market for high-speed, high-powered electronic devices.\u201d\u003C\/p\u003E\u003Cp\u003EIn addition to Conrad, the research team included J. Hicks, M.S. Nevius, F. Wang, K. Shepperd, J. Palmer, J. Kunc, W.A. De Heer and C. Berger, all from Georgia Tech; A. Tejeda from the Institut Jean Lamour, CNES \u2013 Univ. de Nancy and the Synchrotron SOLEIL; A. Taleb-Ibrahimi from the CNRS\/Synchrotron SOLEIL, and F. Bertran and P. Le Fevre from Synchrotron SOLEIL.\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis research was supported by the National Science Foundation Materials Research Science and Engineering Center (MRSEC) at Georgia Tech under Grants DMR-0820382 and DMR-1005880, the W.M. Keck Foundation, and the Partner University Fund from the Embassy of France. The content of the article is the responsibility of the authors and does not necessarily represent the views of the National Science Foundation.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECITATION\u003C\/strong\u003E: Hicks, J., A wide-bandgap metal-semiconductor-metal nanostructure made entirely from graphene, Nature Physics (2012). \u003Ca href=\u0022http:\/\/dx.doi.org\/10.1038\/NPHYS2487\u0022 title=\u0022http:\/\/dx.doi.org\/10.1038\/NPHYS2487\u0022\u003Ehttp:\/\/dx.doi.org\/10.1038\/NPHYS2487\u003C\/a\u003E.\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E177 North Avenue\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia\u0026nbsp; 30332-0181\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EMedia Relations Contact\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E)\u003Cbr \/\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EBy fabricating graphene structures atop nanometer-scale \u201csteps\u201d etched into silicon carbide, researchers have for the first time created a substantial electronic bandgap in the material suitable for room-temperature electronics. Use of nanoscale topography to control the properties of graphene could facilitate fabrication of transistors and other devices, potentially opening the door for developing all-carbon integrated circuits.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have created a substantial electronic bandgap in graphene suitable for room-temperature electronics."}],"uid":"27303","created_gmt":"2012-11-16 18:31:03","changed_gmt":"2016-10-08 03:13:14","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2012-11-18T00:00:00-05:00","iso_date":"2012-11-18T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"171721":{"id":"171721","type":"image","title":"Graphene bandgap","body":null,"created":"1449178999","gmt_created":"2015-12-03 21:43:19","changed":"1475894811","gmt_changed":"2016-10-08 02:46:51","alt":"Graphene bandgap","file":{"fid":"195736","name":"graphene-bandgap.jpg","image_path":"\/sites\/default\/files\/images\/graphene-bandgap_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-bandgap_0.jpg","mime":"image\/jpeg","size":178253,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-bandgap_0.jpg?itok=xxsj8w34"}},"171731":{"id":"171731","type":"image","title":"Graphene bandgap2","body":null,"created":"1449178999","gmt_created":"2015-12-03 21:43:19","changed":"1475894811","gmt_changed":"2016-10-08 02:46:51","alt":"Graphene bandgap2","file":{"fid":"195737","name":"graphene-bandgap2.jpg","image_path":"\/sites\/default\/files\/images\/graphene-bandgap2_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-bandgap2_0.jpg","mime":"image\/jpeg","size":205398,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-bandgap2_0.jpg?itok=z6QTpK_1"}},"171741":{"id":"171741","type":"image","title":"Graphene bandgap3","body":null,"created":"1449178999","gmt_created":"2015-12-03 21:43:19","changed":"1475894811","gmt_changed":"2016-10-08 02:46:51","alt":"Graphene bandgap3","file":{"fid":"195738","name":"graphene-bandgap3.jpg","image_path":"\/sites\/default\/files\/images\/graphene-bandgap3_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-bandgap3_0.jpg","mime":"image\/jpeg","size":144655,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-bandgap3_0.jpg?itok=voS-G2G3"}}},"media_ids":["171721","171731","171741"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"50751","name":"bandgap"},{"id":"50761","name":"Ed Conrad"},{"id":"9116","name":"epitaxial graphene"},{"id":"429","name":"graphene"},{"id":"432","name":"nanoribbon"},{"id":"166937","name":"School of Physics"},{"id":"169534","name":"silicon carbide"}],"core_research_areas":[{"id":"39451","name":"Electronics and Nanotechnology"},{"id":"39471","name":"Materials"}],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News \u0026amp; Publications Office\u003C\/p\u003E\u003Cp\u003E(404) 894-6986\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"132171":{"#nid":"132171","#data":{"type":"news","title":"Study Shows Availability of Hydrogen Controls Chemical Structure of Graphene Oxide","body":[{"value":"\u003Cp\u003EA new study shows that the availability of hydrogen plays a significant role in determining the chemical and structural makeup of graphene oxide, a material that has potential uses in nano-electronics, nano-electromechanical systems, sensing, composites, optics, catalysis and energy storage.\u003C\/p\u003E\u003Cp\u003EThe study also found that after the material is produced, its structural and chemical properties continue to evolve for more than a month as a result of continuing chemical reactions with hydrogen.\u003C\/p\u003E\u003Cp\u003EUnderstanding the properties of graphene oxide \u2013 and how to control them \u2013 is important to realizing potential applications for the material. To make it useful for nano-electronics, for instance, researchers must induce both an electronic band gap and structural order in the material. Controlling the amount of hydrogen in graphene oxide may be the key to manipulating the material properties.\u003C\/p\u003E\u003Cp\u003E\u201cGraphene oxide is a very interesting material because its mechanical, optical and electronic properties can be controlled using thermal or chemical treatments to alter its structure,\u201d said Elisa Riedo, an associate professor in the School of Physics at the Georgia Institute of Technology. \u201cBut before we can get the properties we want, we need to understand the factors that control the material\u2019s structure. This study provides information about the role of hydrogen in the reduction of graphene oxide at room temperature.\u201d\u003C\/p\u003E\u003Cp\u003EThe research, which studied graphene oxide produced from epitaxial graphene, was reported on May 6 in the journal Nature Materials. The research was sponsored by the National Science Foundation, the Materials Research Science and Engineering Center (MRSEC) at Georgia Tech, and by the U.S. Department of Energy.\u003C\/p\u003E\u003Cp\u003EGraphene oxide is formed through the use of chemical and thermal processes that mainly add two oxygen-containing functional groups to the lattice of carbon atoms that make up graphene: epoxide and hydroxyl species. The Georgia Tech researchers began their studies with multilayer expitaxial graphene grown atop a silicon carbide wafer, a technique pioneered by Walt de Heer and his research group at Georgia Tech. Their samples included an average of ten layers of graphene.\u003C\/p\u003E\u003Cp\u003EAfter oxidizing the thin films of graphene using the established Hummers method, the researchers examined their samples using X-ray photo-emission spectroscopy (XPS). Over about 35 days, they noticed the number of epoxide functional groups declining while the number of hydroxyl groups increased slightly. After about three months, the ratio of the two groups finally reached equilibrium.\u003C\/p\u003E\u003Cp\u003E\u201cWe found that the material changed by itself at room temperature without any external stimulation,\u201d said Suenne Kim, a postdoctoral fellow in Riedo\u2019s laboratory. \u201cThe degree to which it was unstable at room temperature was surprising.\u201d\u003C\/p\u003E\u003Cp\u003ECurious about what might be causing the changes, Riedo and Kim took their measurements to Angelo Bongiorno, an assistant professor who studies computational materials chemistry in Georgia Tech\u2019s School of Chemistry and Biochemistry. Bongiorno and graduate student Si Zhou studied the changes using density functional theory, which suggested that hydrogen could be combining with oxygen in the functional groups to form water. That would favor a reduction in the epoxide groups, which is what Riedo and Kim were seeing experimentally.\u003C\/p\u003E\u003Cp\u003E\u201cElisa\u2019s group was doing experimental measurements, while we were doing theoretical calculations,\u201d Bongiorno said. \u201cWe combined our information to come up with the idea that maybe there was hydrogen involved.\u201d\u003C\/p\u003E\u003Cp\u003EThe suspicions were confirmed experimentally, both by the Georgia Tech group and by a research team at the University of Texas at Dallas. This information about the role of hydrogen in determining the structure of graphene oxide suggests a new way to control its properties, Bongiorno noted.\u003C\/p\u003E\u003Cp\u003E\u201cDuring synthesis of the material, we could potentially use this as a tool to change the structure,\u201d he said. \u201cBy understanding how to use hydrogen, we could add it or take it out, allowing us to adjust the relative distribution and concentration of the epoxide and hydroxyl species which control the properties of the material.\u201d\u003C\/p\u003E\u003Cp\u003ERiedo and Bongiorno acknowledge that their material \u2013 based on epitaxial graphene \u2013 may be different from the oxide produced from exfoliated graphene. Producing graphene oxide from flakes of the material involves additional processing, including dissolving in an aqueous solution and then filtering and depositing the material onto a substrate. But they believe hydrogen plays a similar role in determining the properties of exfoliated graphene oxide.\u003C\/p\u003E\u003Cp\u003E\u201cWe probably have a new new form of graphene oxide, one that may be more useful commercially, although the same processes should also be happening within the other form of graphene oxide,\u201d said Bongiorno.\u003C\/p\u003E\u003Cp\u003EThe next steps are to understand how to control the amount of hydrogen in epitaxial graphene oxide, and what conditions may be necessary to affect reactions with the two functional groups. Ultimately, that may provide a way to open an electronic band gap and simultaneously obtain a graphene-based material with electron transport characteristics comparable to those of pristine graphene.\u003C\/p\u003E\u003Cp\u003E\u201cBy controlling the properties of graphene oxide through this chemical and thermal reduction, we may arrive at a material that remains close enough to graphene in structure to maintain the order necessary for the excellent electronic properties, while having the band gap needed to create transistors,\u201d Riedo said. \u201cIt could be that graphene oxide is the way to arrive at that type of material.\u201d\u003C\/p\u003E\u003Cp\u003EBeyond those already mentioned, the paper\u2019s authors included Yike Hu, Claire Berger and Walt de Heer from the School of Physics at Georgia Tech, and Muge Acik and Yves Chabal from the Department of Materials Science and Engineering at the University of Texas at Dallas.\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cem\u003EThis research was supported by the National Science Foundation under grants CMMI-1100290, DMR-0820382 and DMR-0706031, and by the U.S. Department of Energy\u2019s Office of Basic Energy Sciences under grants DE-FG02-06ER46293 and DE-SC001951. The content is solely the responsibility of the principal investigators and does not necessarily represent the official views of the National Science Foundation or the Department of Energy.\u003C\/em\u003E\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E75 Fifth Street, N.W., Suite 314\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia\u0026nbsp; 30308\u0026nbsp; USA\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Robinson (404-385-3364)(\u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E)\u003Cbr \/\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Metastable material continues to evolve for three months after fabrication"}],"field_summary":[{"value":"\u003Cp\u003EA new study shows that the availability of hydrogen plays a significant role in determining the chemical and structural makeup of graphene oxide, a material that has potential uses in nano-electronics, nano-electromechanical systems, sensing, composites, optics, catalysis and energy storage.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have found that the availability of hydrogen controls the structure of graphene oxide."}],"uid":"27303","created_gmt":"2012-05-22 16:01:43","changed_gmt":"2016-10-08 03:12:18","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2012-05-22T00:00:00-04:00","iso_date":"2012-05-22T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"132081":{"id":"132081","type":"image","title":"Studying Graphene Oxide","body":null,"created":"1449178659","gmt_created":"2015-12-03 21:37:39","changed":"1475894759","gmt_changed":"2016-10-08 02:45:59","alt":"Studying Graphene Oxide","file":{"fid":"194701","name":"graphene-hydrogen119.jpg","image_path":"\/sites\/default\/files\/images\/graphene-hydrogen119_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-hydrogen119_0.jpg","mime":"image\/jpeg","size":1513223,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-hydrogen119_0.jpg?itok=hAtjBgvB"}},"132091":{"id":"132091","type":"image","title":"Studying Graphene Oxide2","body":null,"created":"1449178659","gmt_created":"2015-12-03 21:37:39","changed":"1475894759","gmt_changed":"2016-10-08 02:45:59","alt":"Studying Graphene Oxide2","file":{"fid":"194702","name":"graphene-hydrogen62.jpg","image_path":"\/sites\/default\/files\/images\/graphene-hydrogen62_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-hydrogen62_0.jpg","mime":"image\/jpeg","size":1537759,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-hydrogen62_0.jpg?itok=-FD3IilH"}},"132101":{"id":"132101","type":"image","title":"Graphene Oxide Sample","body":null,"created":"1449178659","gmt_created":"2015-12-03 21:37:39","changed":"1475894759","gmt_changed":"2016-10-08 02:45:59","alt":"Graphene Oxide Sample","file":{"fid":"194703","name":"graphene-hydrogen95.jpg","image_path":"\/sites\/default\/files\/images\/graphene-hydrogen95_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/graphene-hydrogen95_0.jpg","mime":"image\/jpeg","size":556983,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/graphene-hydrogen95_0.jpg?itok=yvlPkqHw"}}},"media_ids":["132081","132091","132101"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"141","name":"Chemistry and Chemical Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"9116","name":"epitaxial graphene"},{"id":"429","name":"graphene"},{"id":"34221","name":"graphene oxide"},{"id":"7435","name":"material"},{"id":"34271","name":"mestastable"},{"id":"166928","name":"School of Chemistry and Biochemistry"},{"id":"166937","name":"School of Physics"}],"core_research_areas":[{"id":"39451","name":"Electronics and Nanotechnology"},{"id":"39471","name":"Materials"}],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News \u0026amp; Publications Office\u003C\/p\u003E\u003Cp\u003E(404) 894-6986\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"72427":{"#nid":"72427","#data":{"type":"news","title":"Study Compares Fundamental Techniques for Doping Graphene Sheets","body":[{"value":"\u003Cp\u003ENanotechnology researchers at the Georgia Institute of Technology have conducted the first direct comparison of two fundamental techniques that could be used for chemically doping sheets of two-dimensional graphene for the fabrication of devices and interconnects.\u003C\/p\u003E\n\u003Cp\u003EChemical doping is routinely used in conventional three-dimensional semiconductors to control the density of electron carriers that are essential to the operation of devices such as transistors.  But graphene, a semi-metal available in sheets just one atom thick, has properties very different from traditional materials such as silicon -- though researchers say doping will still be needed for producing electronic devices.\n\u003C\/p\u003E\n\u003Cp\u003EThe bad news is that electronic designers working with graphene won\u0027t be able to simply apply what they\u0027ve been doing with three-dimensional semiconductors -- which would translate to vastly degraded material quality for graphene.  The good news, according to the study, is that graphene doping can be combined with other processes -- and need be applied only to the edges of nanoscale structures being fabricated.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We are learning how to manipulate these two-dimensional sheets of carbon atoms to get some very unusual results that aren\u0027t available with any other material,\u0022 said James Meindl, director of Georgia Tech\u0027s Nanotechnology Research Center, where the research was conducted.  \u0022Doping graphene to try to influence its properties is important to being able to use it effectively.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EDetails of the research were published online in the journal \u003Cem\u003ECarbon\u003C\/em\u003E on October 29th. The research was supported by the Semiconductor Research Corporation (SRC), the Defense Advanced Research Projects Agency (DARPA) through the Interconnect Focus Center, and the National Science Foundation (NSF).\n\u003C\/p\u003E\n\u003Cp\u003EBecause graphene sheets contain so few atoms by area, the substitution of elements such as oxygen or nitrogen for carbon atoms in the lattice -- as in conventional doping -- detracts from the high electron mobility and other properties that make the material interesting.  So the researchers are rethinking the doping process to take advantage of graphene\u0027s unique properties.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022When we work with a three-dimensional semiconductor, we embed the dopant species in the bulk material and then fabricate it into a device,\u0022 said Kevin Brenner, a graduate research assistant in the Georgia Tech School of Electrical and Computer Engineering.  \u0022With graphene, we will dope the material as we process it and fabricate it into devices or interconnects. Doping may be done as part of other fabrication steps such as plasma etching, and that will require us to reinvent the whole process.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EUsing sheets of exfoliated graphene, Brenner and collaborators Raghu Murali and Yinxiao Yang evaluated the effectiveness of two different techniques: edge passivation by coupling electron-beam lithography with a common resist material, and adsorption from coating the surface of the material.  They found that the edge treatment, which chemically reacts with defects created when the material is cut, was a thousand times more efficient at producing carriers in the graphene sheets than the surface treatment.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We will only be working with the edges of the material,\u0022 Brenner explained.  \u0022That will allow us to leave the center pristine and free of defects.  Using this approach, we can maintain very high mobilities and the special properties of graphene while creating very high carrier densities.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EBecause of the two-dimensional nature of the graphene, controlling the edge chemistry can provide control over the bulk properties of the sheet.  \u0022At nanoscale dimensions, the edge atoms tend to dominate over surface adsorption techniques,\u0022 he added.   \u0022With a seven nanometer by seven nanometer graphene device, passivating just one edge C-atom provides the doping equivalent of covering the entire surface.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EFor doping the edge of a graphene structure, the team applied a thin film of hydrogen silsesquioxane (HSQ), a chemical normally used as a resist for etching, then used electron beam lithography to cross-link the material, which added oxygen atoms to the edges to create p-type doping.  The resist and electron beam system combined to provide nanometer-scale control over where the chemical changes took place.\n\u003C\/p\u003E\n\u003Cp\u003EDoping treatment could also be applied using plasma etching, Brenner said.  Controlling the specific atoms used in the plasma, or conducting the etching process in an environment containing specific atoms, could drive those atoms into the edges where they would serve as dopants.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Anytime you create an edge, you have created a location where you can passivate using a dopant,\u0022 he added.  \u0022Instead of needing to embed it in the surface, you can just take the edge that is already there and passivate it with oxygen, nitrogen, hydrogen or other dopant.  It could be almost an effortless process because the doping can be done as part of another step.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EBeyond fabricating electronic devices, Nanotechnology Research Center scientists are interested in using graphene for interconnects, potentially as a replacement for copper.  As interconnect structures become smaller and smaller, the resistivity of copper increases.  Edge-doped graphene sheets exhibit a trend of increasing doping with reduced dimensions, possibly becoming more conductive as their size shrinks below 50 nanometers, making them attractive for nanoscale interconnects.\n\u003C\/p\u003E\n\u003Cp\u003EArmed with basic information about graphene doping, the researchers hope to now begin producing devices to study how graphene actually performs.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Now that we have made a start at understanding how to dope the material, the next step is to begin putting this into nanoscale devices,\u0022 Brenner said.  \u0022We want to see what kind of performance we can get.  That may tell us where graphene\u0027s niche could be as an electronic material.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EMeindl, who has worked with silicon since the dawn of integrated circuits, says it\u0027s too early to predict where graphene will ultimately find commercial applications.  But he says the material\u0027s properties are too interesting not to explore.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022The chances are that something very interesting and unique will develop from the use of graphene,\u0022 he said.  \u0022But we don\u0027t yet have the ability to predict what we will be able to do with this new material.\u0022  \n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\n\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003E\n\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Robinson (404-385-3364)(\u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\n\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003ENanotechnology researchers have conducted the first direct comparison of two fundamental techniques that could be used for chemically doping sheets of two-dimensional graphene for the fabrication of devices and interconnects.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Study examines key process for graphene devices \u0026 interconnects."}],"uid":"27303","created_gmt":"2011-11-05 00:00:00","changed_gmt":"2016-10-08 03:10:38","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2011-11-07T00:00:00-05:00","iso_date":"2011-11-07T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"72428":{"id":"72428","type":"image","title":"Studying graphene doping","body":null,"created":"1449177930","gmt_created":"2015-12-03 21:25:30","changed":"1475894656","gmt_changed":"2016-10-08 02:44:16"},"72429":{"id":"72429","type":"image","title":"SEM image of doping study","body":null,"created":"1449177930","gmt_created":"2015-12-03 21:25:30","changed":"1475894656","gmt_changed":"2016-10-08 02:44:16"},"72430":{"id":"72430","type":"image","title":"Studying graphene doping","body":null,"created":"1449177930","gmt_created":"2015-12-03 21:25:30","changed":"1475894656","gmt_changed":"2016-10-08 02:44:16"}},"media_ids":["72428","72429","72430"],"related_links":[{"url":"http:\/\/www.nrc.gatech.edu\/","title":"Nanotechnology Research Center"},{"url":"http:\/\/www.ece.gatech.edu\/","title":"School of Electrical and Computer Engineering"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"}],"keywords":[{"id":"1928","name":"devices"},{"id":"8458","name":"doping"},{"id":"429","name":"graphene"},{"id":"430","name":"interconnects"},{"id":"2783","name":"James Meindl"},{"id":"107","name":"Nanotechnology"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"70182":{"#nid":"70182","#data":{"type":"news","title":"Controlling Silicon Evaporation Improves Quality of Graphene","body":[{"value":"\u003Cp\u003EScientists from the Georgia Institute of Technology have for the first time provided details of their \u0022confinement controlled sublimation\u0022 technique for growing high-quality layers of epitaxial graphene on silicon carbide wafers.  The technique relies on controlling the vapor pressure of gas-phase silicon in the high-temperature furnace used for fabricating the material.\u003C\/p\u003E\n\u003Cp\u003EThe basic principle for growing thin layers of graphene on silicon carbide requires heating the material to about 1,500 degrees Celsius under high vacuum.  The heat drives off the silicon, leaving behind one or more layers of graphene.  But uncontrolled evaporation of silicon can produce poor quality material useless to designers of electronic devices.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022For growing high-quality graphene on silicon carbide, controlling the evaporation of silicon at just the right temperature is essential,\u0022 said Walt de Heer, a professor who pioneered the technique in the Georgia Tech School of Physics.  \u0022By precisely controlling the rate at which silicon comes off the wafer, we can control the rate at which graphene is produced.  That allows us to produce very nice layers of epitaxial graphene.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EDe Heer and his team begin by placing a silicon carbide wafer into an enclosure made of graphite.  A small hole in the container controls the escape of silicon atoms as the one-square-centimeter wafer is heated, maintaining the rate of silicon evaporation and condensation near its thermal equilibrium.  The growth of epitaxial graphene can be done in a vacuum or in the presence of an inert gas such as argon, and can be used to produce both single layers and multiple layers of the material.  \n\u003C\/p\u003E\n\u003Cp\u003E\u0022This technique seems to be completely in line with what people might one day do in fabrication facilities,\u0022 de Heer said. \u0022We believe this is quite significant in allowing us to rationally and reproducibly grow graphene on silicon carbide. We feel we now understand the process, and believe it could be scaled up for electronics manufacturing.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe technique for growing large-area layers of epitaxial graphene was described this week in the Early Edition of the journal \u003Cem\u003EProceedings of the National Academy of Sciences\u003C\/em\u003E.  The research has been supported by the National Science Foundation through the Georgia Tech Materials Research Science and Engineering Center (MRSEC), the Air Force Office of Scientific Research, and the W.M. Keck Foundation.\n\u003C\/p\u003E\n\u003Cp\u003EThe paper also describes a technique for growing narrow graphene ribbons, a process de Heer\u0027s group has called \u0022templated growth.\u0022  That technique, which could be useful for making graphene interconnects, was first described in October 2010 in the journal \u003Cem\u003ENature Nanotechnology\u003C\/em\u003E.\n\u003C\/p\u003E\n\u003Cp\u003EThe templated growth technique involves etching patterns into silicon carbide surfaces using conventional nanolithography processes.  The patterns serve as templates directing the growth of graphene structures on portions of the patterned surfaces.  The technique forms nanoribbons of specific widths without the use of electron beams or other destructive cutting techniques.  Graphene nanoribbons produced with these templates have smooth edges that avoid problems with electron scattering.\n\u003C\/p\u003E\n\u003Cp\u003ETogether, the two techniques provide researchers with the flexibility to produce graphene in forms appropriate to different needs, de Heer noted.  Large-area sheets of graphene may be grown on both the carbon-terminated and silicon-terminated sides of a silicon carbide wafer, while the narrow ribbons may be grown on the silicon-terminated side.  Because of different processing techniques, only one side of a particular wafer can be used.  \n\u003C\/p\u003E\n\u003Cp\u003EThe Georgia Tech research team -- which includes Claire Berger, Ming Ruan, Mike Sprinkle, Xuebin Li, Yike Hu, Baiqian Zhang, John Hankinson and Edward Conrad -- has so far fabricated structures as narrow as 10 nanometers using the templated growth technique.  These nanowires exhibit interesting quantum transport properties.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We can make very good quantum wires using the templated growth technique,\u0022 de Heer said. \u0022We can make large structures and devices that demonstrate the Quantum Hall Effect, which is important for many applications.  We have demonstrated that templated growth can go all the way down to the nanoscale, and that the properties get even better there.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EDevelopment of the sublimation technique arose from efforts to protect the growing graphene from oxygen and other contaminants in the furnace.  To address the quality concerns, the research team tried enclosing the wafer in a graphite container from which some silicon gas was permitted to leak out.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We soon realized that graphene grown in the container was much better than what we had been producing,\u0022 de Heer recalled. \u0022Originally, we thought it was because we were protecting it from contaminants.  Later, we realized it was because we were controlling the evaporation of silicon.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EEpitaxial graphene may be the basis for a new generation of high-performance devices that will take advantage of the material\u0027s unique properties in applications where higher costs can be justified.  Silicon, today\u0027s electronic material of choice, will continue to be used in applications where high-performance is not required, de Heer said.\n\u003C\/p\u003E\n\u003Cp\u003EThough researchers are still struggling to design nanometer-scale epitaxial graphene devices that take advantage of the material\u0027s unique properties, de Heer is confident that will ultimately be done.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022These techniques allow us to make accurate nanostructures and seem to be very promising for making the nanoscale devices that we need,\u0022 he said. \u0022While there are serious challenges ahead for using graphene in electronics, we have overcome roadblocks before.\u0022\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\n\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003E\n\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Robinson (404-385-3364)(\u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\n\u003C\/p\u003E\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EGeorgia Tech scientists have for the first time provided details of their \u0022confinement controlled sublimation\u0022 technique for growing high-quality layers of epitaxial graphene on silicon carbide wafers.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Scientists reveal details of their graphene fabrication process."}],"uid":"27303","created_gmt":"2011-09-22 00:00:00","changed_gmt":"2016-10-08 03:10:14","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2011-09-22T00:00:00-04:00","iso_date":"2011-09-22T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"70183":{"id":"70183","type":"image","title":"Researchers with graphene furnace","body":null,"created":"1449177304","gmt_created":"2015-12-03 21:15:04","changed":"1475894616","gmt_changed":"2016-10-08 02:43:36"},"70184":{"id":"70184","type":"image","title":"Graphene furnace","body":null,"created":"1449177304","gmt_created":"2015-12-03 21:15:04","changed":"1475894616","gmt_changed":"2016-10-08 02:43:36"}},"media_ids":["70183","70184"],"related_links":[{"url":"http:\/\/www.physics.gatech.edu\/","title":"Georgia Tech School of Physics"},{"url":"http:\/\/www.mrsec.gatech.edu\/","title":"Materials Research Science and Engineering Center"},{"url":"http:\/\/www.graphene.gatech.edu\/","title":"Epitaxial Graphene Lab"},{"url":"https:\/\/www.physics.gatech.edu\/user\/walter-de-heer","title":"Walt de Heer"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"10880","name":"epitaxial"},{"id":"14402","name":"furnace"},{"id":"429","name":"graphene"},{"id":"960","name":"physics"},{"id":"169534","name":"silicon carbide"},{"id":"12422","name":"Walt de Heer"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"66351":{"#nid":"66351","#data":{"type":"news","title":"Flower-Like Defects May Help Graphene Respond to Stress","body":[{"value":"\u003Cp\u003EBeyond its ability to conduct electrons almost without resistance, the nanomaterial graphene also has amazing mechanical properties, including high strength that could one day make it useful in lightweight, robust structures.  But this material is not without flaws -- including a family of flower-like defects that could detract from its electronic and mechanical properties. \u003C\/p\u003E\n\u003Cp\u003EIn a paper published in the journal \u003Cem\u003EPhysical Review B\u003C\/em\u003E, researchers at the Georgia Institute of Technology and the National Institute of Standards and Technology (NIST) have described a family of seven potential defect structures that may appear in sheets of graphene and imaged examples of the lowest-energy defect in the family. \n\u003C\/p\u003E\n\u003Cp\u003EThe defects may arise to help relieve mechanical stress in graphene\u0027s carbon-atom honeycomb structure by allowing atoms to spread out and occupy slightly more space.  Such stress may arise during the growth of graphene or by stretching the graphene sheet.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022For an engineer interested in the mechanical properties of graphene to create atom-thick membranes, for instance, it would be very important to understand these kinds of properties, which could give rise to plastic deformation of the material,\u0022 said Phillip First, one of the paper\u0027s co-authors and a professor in the Georgia Tech School of Physics.  \u0022For instance, it may be that these defects are just one part of the kinetic pathway to failure for a strained sheet of graphene.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EFor electronic applications, the defects could deflect electrons and cause backscattering that would increase the resistance of the material -- like a rock in a stream slows the flow of water.\u003Cbr \/\u003E\nHowever, First says improved growth techniques developed since the defect study began may eliminate that concern.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022With the growth techniques that have now been developed using silicon carbide, we typically do not see these defects,\u0022 he noted.  \u0022The defects occur on material that we know to be of a lower quality because of the growth conditions or substrate preparation.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EDefects can appear due to the movement of carbon atoms at high temperatures, explained NIST Fellow Joseph Stroscio.  Rearrangements of graphene that require the least amount of energy involve switching from the standard six-member carbon rings to structures containing either five or seven atoms.  The NIST researchers have discovered that stringing five- and seven-member rings together in closed loops creates a new type of defect or grain boundary loop in the honeycomb lattice.\n\u003C\/p\u003E\n\u003Cp\u003EAccording to NIST researcher Eric Cockayne, the fabrication process plays a big role in creating the defects.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022As the graphene forms under high heat, sections of the lattice can come loose and rotate,\u0022 he said.  \u0022As the graphene cools, these rotated sections link back up with the lattice, but in an irregular way.  It\u0027s almost as if patches of the graphene were cut out with scissors, turned clockwise, and made to fit back into the same place.  Only it really doesn\u0027t fit, which is why we get these flowers.\u0022\n\u003C\/p\u003E\n\u003Cp\u003ESo far, only the flower defect, which is composed of six pairs of five- and seven-atom rings, has been observed.  Modeling of graphene\u0027s atomic structure by the NIST team suggests there might be a veritable bouquet of flower-like configurations.  These configurations -- seven in all -- would each possess its own unique mechanical and electrical properties, Cockayne said.\n\u003C\/p\u003E\n\u003Cp\u003EFirst hopes the team can continue studying the defects, both to learn whether their formation can be controlled and to clarify the role of defects in the material\u0027s mechanical properties.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Graphene is strong and light, so the mechanical properties are of great interest,\u0022 he noted.  \u0022Understanding just how it rips apart is an interesting question that has important implications.  But even with these defects, graphene is still spectacularly strong.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EGeorgia Tech contributions to this work were funded by the Semiconductor Research Corporation (NRI-INDEX) and by the National Science Foundation through the Georgia Tech Materials Research Science and Engineering Center (MRSEC) under grants DMR-0804908 and DMR-0820382.\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cem\u003EMark Esser of NIST also contributed to this article.\u003C\/em\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\n\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003E\n\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Robinson (404-385-3364)(\u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\n\u003C\/p\u003E\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EIn a new study, researchers at the Georgia Institute of Technology and the National Institute of Standards and Technology (NIST) have described a family of seven potential defect structures that may appear in sheets of graphene.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers describe family of defects in graphene."}],"uid":"27303","created_gmt":"2011-06-01 00:00:00","changed_gmt":"2016-10-08 03:08:49","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2011-06-01T00:00:00-04:00","iso_date":"2011-06-01T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"66352":{"id":"66352","type":"image","title":"Graphene defect structures","body":null,"created":"1449176931","gmt_created":"2015-12-03 21:08:51","changed":"1475894589","gmt_changed":"2016-10-08 02:43:09"}},"media_ids":["66352"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"2504","name":"conductance"},{"id":"531","name":"defect"},{"id":"429","name":"graphene"},{"id":"9115","name":"MRSEC"},{"id":"13305","name":"Phillip First"},{"id":"960","name":"physics"},{"id":"167229","name":"stress"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"65044":{"#nid":"65044","#data":{"type":"news","title":"Technique Produces Graphene Nanoribbons with Metallic Properties","body":[{"value":"\u003Cp\u003EA new \u0022templated growth\u0022 technique for fabricating nanoribbons of epitaxial graphene has produced structures just 15 to 40 nanometers wide that conduct current with almost no resistance.  These structures could address the challenge of connecting graphene devices made with conventional architectures -- and set the stage for a new generation of devices that take advantage of the quantum properties of electrons.\u003C\/p\u003E\n\u003Cp\u003E\u0022We can now make very narrow, conductive nanoribbons that have quantum ballistic properties,\u0022 said Walt de Heer, a professor in the School of Physics at the Georgia Institute of Technology.  \u0022These narrow ribbons become almost like a perfect metal.  Electrons can move through them without scattering, just like they do in carbon nanotubes.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EDe Heer discussed recent results of this graphene growth process March 21st at the American Physical Society\u2019s March 2011 Meeting in Dallas.  The research was sponsored by the National Science Foundation-supported Materials Research Science and Engineering Center (MRSEC).\n\u003C\/p\u003E\n\u003Cp\u003EFirst reported Oct. 3 in the advance online edition of the journal \u003Cem\u003ENature Nanotechnology\u003C\/em\u003E, the new fabrication technique allows production of epitaxial graphene structures with smooth edges.  Earlier fabrication techniques that used electron beams to cut graphene sheets produced nanoribbon structures with rough edges that scattered electrons, causing interference.  The resulting nanoribbons had properties more like insulators than conductors.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022In our templated growth approach, we have essentially eliminated the edges that take away from the desirable properties of graphene,\u0022 de Heer explained.  \u0022The edges of the epitaxial graphene merge into the silicon carbide, producing properties that are really quite interesting.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe templated growth technique begins with etching patterns into the silicon carbide surfaces on which epitaxial graphene is grown.  The patterns serve as templates directing the growth of graphene structures, allowing the formation of nanoribbons and other structures of specific widths and shapes without the use of cutting techniques that produce the rough edges.\n\u003C\/p\u003E\n\u003Cp\u003EIn creating these graphene nanostructures, de Heer and his research team first use conventional microelectronics techniques to etch tiny \u0022steps\u0022  -- or contours -- into a silicon carbide wafer whose surface has been made extremely flat.  They then heat the contoured wafer to approximately 1,500 degrees Celsius, which initiates melting that polishes any rough edges left by the etching process.\n\u003C\/p\u003E\n\u003Cp\u003EEstablished techniques are then used for growing graphene from silicon carbide by driving the silicon atoms from the surface.  Instead of producing a consistent layer of graphene across the entire surface of the wafer, however, the researchers limit the heating time so that graphene grows only on portions of the contours.\n\u003C\/p\u003E\n\u003Cp\u003EThe width of the resulting nanoribbons is proportional to the depth of the contours, providing a mechanism for precisely controlling the nanoribbon structures.  To form complex structures, multiple etching steps can be carried out to create complex templates.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022This technique allows us to avoid the complicated e-beam lithography steps that people have been using to create structures in epitaxial graphene,\u0022 de Heer noted.  \u0022We are seeing very good properties that show these structures can be used for real electronic applications.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003ESince publication of the \u003Cem\u003ENature Nanotechnology\u003C\/em\u003E paper, de Heer\u0027s team has been refining its technique.  \u0022We have taken this to an extreme -- the cleanest and narrowest ribbons we can make,\u0022 he said.  \u0022We expect to be able to do everything we need with the size ribbons that we are able to make right now, though we probably could reduce the width to 10 nanometers or less.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EWhile the Georgia Tech team is continuing to develop high-frequency transistors -- perhaps even at the terahertz range -- its primary effort now focuses on developing quantum devices, de Heer said.  Such devices were envisioned in the patents Georgia Tech holds on various epitaxial graphene processes.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022This means that the way we will be doing graphene electronics will be different,\u0022 he explained.  \u0022We will not be following the model of using standard field-effect transistors (FETs), but will pursue devices that use ballistic conductors and quantum interference. We are headed straight into using the electron wave effects in graphene.\u0022\n\u003C\/p\u003E\n\u003Cp\u003ETaking advantage of the wave properties will allow electrons to be manipulated with techniques similar to those used by optical engineers.  For instance, switching may be carried out using interference effects -- separating beams of electrons and then recombining them in opposite phases to extinguish the signals.\n\u003C\/p\u003E\n\u003Cp\u003EQuantum devices would be smaller than conventional transistors and operate at lower power.  Because of its ability to transport electrons with virtually no resistance, epitaxial graphene may be the ideal material for such devices, de Heer said.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Using the quantum properties of electrons rather than the standard charged-particle properties means opening up new ways of looking at electronics,\u0022 he predicted.  \u0022This is probably the way that electronics will evolve, and it appears that graphene is the ideal material for making this transition.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EDe Heer\u0027s research team hopes to demonstrate a rudimentary switch operating on the quantum interference principle within a year.  \n\u003C\/p\u003E\n\u003Cp\u003EEpitaxial graphene may be the basis for a new generation of high-performance devices that will take advantage of the material\u0027s unique properties in applications where higher costs can be justified.  Silicon, today\u0027s electronic material of choice, will continue to be used in applications where high-performance is not required, de Heer said.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022This is an important step in the process,\u0022 he added.  \u0022There are going to be a lot of surprises as we move into these quantum devices and find out how they work.  We have good reason to believe that this can be the basis for a new generation of transistors based on quantum interference.\u0022\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E\nAtlanta, Georgia 30308 USA\n\u003C\/strong\u003E\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Robinson (404-385-3364)(\u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\n\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EA new \u0022templated growth\u0022 technique for fabricating nanoribbons of epitaxial graphene has produced structures just 15 to 40 nanometers wide that conduct current with almost no resistance.  These structures could address the challenge of connecting graphene devices.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have made graphene nanoribbons with metallic properties."}],"uid":"27303","created_gmt":"2011-03-21 00:00:00","changed_gmt":"2016-10-08 03:08:26","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2011-03-21T00:00:00-04:00","iso_date":"2011-03-21T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"65045":{"id":"65045","type":"image","title":"Growing epitaxial graphene","body":null,"created":"1449176783","gmt_created":"2015-12-03 21:06:23","changed":"1475894574","gmt_changed":"2016-10-08 02:42:54","alt":"Growing epitaxial graphene","file":{"fid":"192147","name":"tis35461.jpg","image_path":"\/sites\/default\/files\/images\/tis35461_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tis35461_0.jpg","mime":"image\/jpeg","size":1731501,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tis35461_0.jpg?itok=Q2grkYwo"}},"65046":{"id":"65046","type":"image","title":"Prof. Walt de Heer","body":null,"created":"1449176783","gmt_created":"2015-12-03 21:06:23","changed":"1475894574","gmt_changed":"2016-10-08 02:42:54","alt":"Prof. Walt de Heer","file":{"fid":"192148","name":"toh35777.jpg","image_path":"\/sites\/default\/files\/images\/toh35777_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/toh35777_0.jpg","mime":"image\/jpeg","size":1603740,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/toh35777_0.jpg?itok=GCENVzgL"}},"65047":{"id":"65047","type":"image","title":"Growing expitaxial graphene","body":null,"created":"1449176783","gmt_created":"2015-12-03 21:06:23","changed":"1475894574","gmt_changed":"2016-10-08 02:42:54","alt":"Growing expitaxial graphene","file":{"fid":"192149","name":"tfu35461.jpg","image_path":"\/sites\/default\/files\/images\/tfu35461_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tfu35461_0.jpg","mime":"image\/jpeg","size":65166,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tfu35461_0.jpg?itok=4hcNTgqa"}}},"media_ids":["65045","65046","65047"],"related_links":[{"url":"http:\/\/www.physics.gatech.edu\/","title":"Georgia Tech School of Physics"},{"url":"http:\/\/www.mrsec.gatech.edu\/","title":"Materials Research Science and Engineering Center"},{"url":"https:\/\/www.physics.gatech.edu\/user\/walter-de-heer","title":"Walt de Heer"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"141","name":"Chemistry and Chemical Engineering"},{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"10890","name":"conductor"},{"id":"9116","name":"epitaxial graphene"},{"id":"429","name":"graphene"},{"id":"12423","name":"nanoribbons"},{"id":"4827","name":"resistance"},{"id":"12422","name":"Walt de Heer"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"63409":{"#nid":"63409","#data":{"type":"news","title":"Expitaxial Graphene Shows Promise for Replacing Silicon in Electronics","body":[{"value":"\u003Cp\u003EMove over silicon.  There\u0027s a new electronic material in town, and it goes fast.\n\u003C\/p\u003E\n\u003Cp\u003EThat material, the focus of the 2010 Nobel Prize in physics, is graphene -- a fancy name for extremely thin layers of ordinary carbon atoms arranged in a \u0022chicken-wire\u0022 lattice. These layers, sometimes just a single atom thick, conduct electricity with virtually no resistance, very little heat generation -- and less power consumption than silicon.\n\u003C\/p\u003E\n\u003Cp\u003EWith silicon device fabrication approaching its physical limits, many researchers believe graphene can provide a new platform material that would allow the semiconductor industry to continue its march toward ever-smaller and faster electronic devices -- progress described in Moore\u0027s Law. Though graphene will likely never replace silicon for everyday electronic applications, it could take over as the material of choice for high-performance devices. \n\u003C\/p\u003E\n\u003Cp\u003EAnd graphene could ultimately spawn a new generation of devices designed to take advantage of its unique properties. \n\u003C\/p\u003E\n\u003Cp\u003ESince 2001, Georgia Tech has become a world leader in developing epitaxial graphene, a specific type of graphene that can be grown on large wafers and patterned for use in electronics manufacturing. In a recent paper published in the journal \u003Cem\u003ENature Nanotechnology\u003C\/em\u003E, Georgia Tech researchers reported fabricating an array of 10,000 top-gated transistors on a 0.24 square centimeter chip, an achievement believed to be the highest density reported so far in graphene devices. \n\u003C\/p\u003E\n\u003Cp\u003EIn creating that array, they also demonstrated a clever new approach for growing complex graphene patterns on templates etched into silicon carbide. The new technique offered the solution to one of the most difficult issues that had been facing graphene electronics. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022This is a significant step toward electronics manufacturing with graphene,\u0022 said Walt de Heer, a professor in Georgia Tech\u0027s School of Physics who pioneered the development of graphene for high-performance electronics. \u0022This is another step showing that our method of working with epitaxial graphene grown on silicon carbide is the right approach and the one that will probably be used for making graphene electronics.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EUnrolled Carbon Nanotubes\u003C\/strong\u003E \n\u003C\/p\u003E\n\u003Cp\u003EFor de Heer, the story of graphene begins with carbon nanotubes, tiny cylindrical structures considered miraculous when they first began to be studied by scientists in 1991. De Heer was among the researchers excited about the properties of nanotubes, whose unique arrangement of carbon atoms gave them physical and electronic properties that scientists believed could be the foundation for a new generation of electronic devices. \n\u003C\/p\u003E\n\u003Cp\u003ECarbon nanotubes still have attractive properties, but the ability to grow them consistently -- and to incorporate them in high-volume electronics applications -- has so far eluded researchers. De Heer realized before others that carbon nanotubes would probably never be used for high-volume electronic devices. \n\u003C\/p\u003E\n\u003Cp\u003EBut he also realized that the key to the attractive electronic properties of the nanotubes was the lattice created by the carbon atoms. Why not simply grow that lattice on a flat surface, and use fabrication techniques proven in the microelectronics industry to create devices in much the same way as silicon integrated circuits? \n\u003C\/p\u003E\n\u003Cp\u003EBy heating silicon carbide -- a widely-used electronic material -- de Heer and his colleagues were able to drive silicon atoms from the surface, leaving just the carbon lattice in thin layers of graphene large enough to grow the kinds of electronic devices familiar to a generation of electronics designers.\n\u003C\/p\u003E\n\u003Cp\u003EThat process was the basis for a patent filed in 2003, and for initial research support from chip-maker Intel. Since then, de Heer\u0027s group has published dozens of papers and helped spawn other research groups also using epitaxial graphene for electronic devices. Though scientists are still learning about the material, companies such as IBM have launched research programs based on epitaxial graphene, and agencies such as the National Science Foundation (NSF) and Defense Advanced Research Projects Agency (DARPA) have invested in developing the material for future electronics applications. \n\u003C\/p\u003E\n\u003Cp\u003EGeorgia Tech\u0027s work on developing epitaxial graphene for manufacturing electronic devices was recognized in the background paper produced by the Royal Swedish Academy of Sciences as part of the Nobel Prize documentation. \n\u003C\/p\u003E\n\u003Cp\u003EThe race to find commercial applications for graphene is intense, with researchers from the United States, Europe, Japan and Singapore engaged in well-funded efforts. Since awarding of the Nobel to a group from the United Kingdom, the flood of news releases about graphene developments has grown. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022Our epitaxial graphene is now used around the world by many research laboratories,\u0022 de Heer noted. \u0022We are probably at the stage where silicon was in the 1950s. This is the beginning of something that is going to be very large and important.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ESilicon \u0022Running Out of Gas\u0022\u003C\/strong\u003E \n\u003C\/p\u003E\n\u003Cp\u003EA new electronics material is needed because silicon is running out of miniaturization room. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022Primarily, we\u0027ve gotten the speed increases from silicon by continually shrinking feature sizes and improving interconnect technology,\u0022 said Dennis Hess, director of the National Science Foundation-sponsored Materials Research Science and Engineering Center (MRSEC) established at Georgia Tech to study future electronic materials, starting with epitaxial graphene. \u0022We are at the point where in less than 10 years, we won\u0027t be able to shrink feature sizes any farther because of the physics of the device operation. That means we will either have to change the type of device we make, or change the electronic material we use.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003EIt\u0027s a matter of physics. At the very small size scales needed to create ever more dense device arrays, silicon generates too much resistance to electron flow, creating more heat than can be dissipated and consuming too much power. \n\u003C\/p\u003E\n\u003Cp\u003EGraphene has no such restrictions, and in fact, can provide electron mobility as much as 100 times better than silicon. De Heer believes his group has developed the roadmap for the future of high-performance electronics -- and that it is paved with epitaxial graphene. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022We have basically developed a whole scheme for making electronics out of graphene,\u0022 he said. \u0022We have set down what we believe will be the ground rules for how that will work, and we have the key patents in place.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003ESilicon, of course, has matured over many generations through constant research and improvement. De Heer and Hess agree that silicon will always be around, useful for low-cost consumer products such as iPods, toasters, personal computers and the like. \n\u003C\/p\u003E\n\u003Cp\u003EDe Heer expects graphene to find its niche doing things that couldn\u0027t otherwise be done. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022We\u0027re not trying to do something cheaper or better; we\u0027re going to do things that can\u0027t be done at all with silicon,\u0022 he said. \u0022Making electronic devices as small as a molecule, for instance, cannot be done with silicon, but in principle could be done with graphene. The key question is how to extend Moore\u0027s Law in a post-CMOS world.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003EUnlike the carbon nanotubes he studied in the 1990s, de Heer sees no major problems ahead for the development of epitaxial graphene. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022That graphene is going to be a major player in the electronics of the future is no longer in doubt,\u0022 he said. \u0022We don\u0027t see any real roadblocks ahead. There are no flashing red lights or other signs that seem to say that this won\u0027t work. All of the issues we see relate to improving technical issues, and we know how to do that.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMaking the Best Graphene\u003C\/strong\u003E \n\u003C\/p\u003E\n\u003Cp\u003ESince beginning the exploration of graphene in 2001, de Heer and his research team have made continuous improvements in the quality of the material they produce, and those improvements have allowed them to demonstrate a number of physical properties -- such as the Quantum Hall Effect -- that verify the unique properties of the material.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022The properties that we see in our epitaxial graphene are similar to what we have calculated for an ideal theoretical sheet of graphene suspended in the air,\u0022 said Claire Berger, a research scientist in the Georgia Tech School of Physics who also has a faculty appointment at the Centre National de la Recherche Scientifique in France. \u0022We see these properties in the electron transport and we see these properties in all kinds of spectroscopy. Everything that is supposed to be occurring in a single sheet of graphene we are seeing in our systems.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003EKey to the material\u0027s future, of course, is the ability to make electronic devices that work consistently. The researchers believe they have almost reached that point. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022All of the properties that epitaxial graphene needs to make it viable for electronic devices have been proven in this material,\u0022 said Ed Conrad, a professor in Georgia Tech\u0027s School of Physics who is also a MRSEC member. \u0022We have shown that we can make macroscopic amounts of this material, and with the devices that are scalable, we have the groundwork that could really make graphene take off.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003EReaching higher and higher device density is also important, along with the ability to control the number of layers of graphene produced. The group has demonstrated that in their multilayer graphene, each layer retains the desired properties. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022Multilayer graphene has different stacking than graphite, the material found in pencils,\u0022 Conrad noted. \u0022In graphite, every layer is rotated 60 degrees and that\u0027s the only way that nature can do it. When we grow graphene on silicon carbide, the layers are rotated 30 degrees. When that happens, the symmetry of the system changes to make the material behave the way we want it to.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EEpitaxial Versus Exfoliated\u003C\/strong\u003E\n\u003C\/p\u003E\n\u003Cp\u003EMuch of the world\u0027s graphene research -- including work leading to the Nobel -- involved the study of exfoliated graphene: layers of the material removed from a block of graphite, originally with tape. While that technique produces high-quality graphene, it\u0027s not clear how that could be scaled up for industrial production. \n\u003C\/p\u003E\n\u003Cp\u003EWhile agreeing that the exfoliated material has produced useful information about graphene properties, de Heer dismisses it as \u0022a science project\u0022 unlikely to have industrial electronics application. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022Electronics companies are not interested in graphene flakes,\u0022 he said. \u0022They need industrial graphene, a material that can be scaled up for high-volume manufacturing. Industry is now getting more and more interested in what we are doing.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003EDe Heer says Georgia Tech\u0027s place in the new graphene world is to focus on electronic applications. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022We are not really trying to compete with these other groups,\u0022 he said. \u0022We are really trying to create a practical electronic material. To do that, we will have to do many things right, including fabricating a scalable material that can be made as large as a wafer. It will have to be uniform and able to be processed using industrial methods.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResolving Technical Issues\u003C\/strong\u003E \n\u003C\/p\u003E\n\u003Cp\u003EAmong the significant technical issues facing graphene devices has been electron scattering that occurs at the boundaries of nanoribbons. If the edges aren\u0027t perfectly smooth -- as usually happens when the material is cut with electron beams -- the roughness bounces electrons around, creating resistance and interference. \n\u003C\/p\u003E\n\u003Cp\u003ETo address that problem, de Heer and his team recently developed a new \u0022templated growth\u0022 technique for fabricating nanometer-scale graphene devices. The technique involves etching patterns into the silicon carbide surfaces on which epitaxial graphene is grown. The patterns serve as templates directing the growth of graphene structures, allowing the formation of nanoribbons of specific widths without the use of e-beams or other destructive cutting techniques. Graphene nanoribbons produced with these templates have smooth edges that avoid electron-scattering problems. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022Using this approach, we can make very narrow ribbons of interconnected graphene without the rough edges,\u0022 said de Heer. \u0022Anything that can be done to make small structures without having to cut them is going to be useful to the development of graphene electronics because if the edges are too rough, electrons passing through the ribbons scatter against the edges and reduce the desirable properties of graphene.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003EIn nanometer-scale graphene ribbons, quantum confinement makes the material behave as a semiconductor suitable for creation of electronic devices. But in ribbons a micron or so wide, the material acts as a conductor. Controlling the depth of the silicon carbide template allows the researchers to create these different structures simultaneously, using the same growth process. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022The same material can be either a conductor or a semiconductor depending on its shape,\u0022 noted de Heer. \u0022One of the major advantages of graphene electronics is to make the device leads and the semiconducting ribbons from the same material. That\u0027s important to avoid electrical resistance that builds up at junctions between different materials.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003EAfter formation of the nanoribbons, the researchers apply a dielectric material and metal gate to construct field-effect transistors. While successful fabrication of high-quality transistors demonstrates graphene\u0027s viability as an electronic material, de Heer sees them as only the first step in what could be done with the material. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022When we manage to make devices well on the nanoscale, we can then move on to make much smaller and finer structures that will go beyond conventional transistors to open up the possibility for more sophisticated devices that use electrons more like light than particles,\u0022 he said. \u0022If we can factor quantum mechanical features into electronics, that is going to open up a lot of new possibilities.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ECollaborations with Other Groups\u003C\/strong\u003E \n\u003C\/p\u003E\n\u003Cp\u003EBefore engineers can use epitaxial graphene for the next generation of electronic devices, they will have to understand its unique properties. As part of that process, Georgia Tech researchers are collaborating with scientists at the National Institute of Standards and Technology (NIST). The collaboration has produced new insights into how electrons behave in graphene. \n\u003C\/p\u003E\n\u003Cp\u003EIn a recent paper published in the journal \u003Cem\u003ENature Physics\u003C\/em\u003E, the Georgia Tech-NIST team described for the first time how the orbits of electrons are distributed spatially by magnetic fields applied to layers of epitaxial graphene. They also found that these electron orbits can interact with the substrate on which the graphene is grown, creating energy gaps that affect how electron waves move through the multilayer material. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022The regular pattern of magnetically-induced energy gaps in the graphene surface creates regions where electron transport is not allowed,\u0022 said Phillip N. First, a professor in the Georgia Tech School of Physics and MRSEC member. \u0022Electron waves would have to go around these regions, requiring new patterns of electron wave interference. Understanding this interference would be important for some bi-layer graphene devices that have been proposed.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003EEarlier NIST collaborations led to improved understanding of graphene electron states, and the way in which low temperature and high magnetic fields can affect energy levels. The researchers also demonstrated that atomic-scale moir\u00e9 patterns, an interference pattern that appears when two or more graphene layers are overlaid, can be used to measure how sheets of graphene are stacked. \n\u003C\/p\u003E\n\u003Cp\u003EIn a collaboration with the U.S. Naval Research Laboratory and University of Illinois at Urbana-Champaign, a group of Georgia Tech professors developed a simple and quick one-step process for creating nanowires on graphene oxide. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022We\u0027ve shown that by locally heating insulating graphene oxide, both the flakes and the epitaxial varieties, with an atomic force microscope tip, we can write nanowires with dimensions down to 12 nanometers,\u0022 said Elisa Riedo, an associate professor in the Georgia Tech School of Physics and a MRSEC member. \u0022And we can tune their electronic properties to be up to four orders of magnitude more conductive.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EA New Industrial Revolution?\u003C\/strong\u003E \n\u003C\/p\u003E\n\u003Cp\u003EThough graphene can be grown and fabricated using processes similar to those of silicon, it is not easily compatible with silicon. That means companies adopting it will also have to build new fabrication facilities -- an expensive investment. Consequently, de Heer believes industry will be cautious about moving into a new graphene world. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022Silicon technology is completely entrenched and well developed,\u0022 he admitted. \u0022We can adopt many of the processes of silicon, but we can\u0027t easily integrate ourselves into silicon. Because of that, we really need a major paradigm shift. But for the massive electronics industry, that will not happen easily or gently.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003EHe draws an analogy to steamships and passenger trains at the dawn of the aviation age. At some point, it became apparent that airliners were going to replace both ocean liners and trains in providing first-class passenger service. Though the cost of air travel was higher, passengers were willing to pay a premium for greater speed. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022We are going to see a coexistence of technologies for a while, and how the hybridization of graphene and silicon electronics is going to happen remains up in the air,\u0022 de Heer predicted. \u0022That is going to take decades, though in the next ten years we are probably going to see real commercial devices that involve graphene.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003E\u003Cem\u003E\u003Cstrong\u003EThis article originally appeared in Research Horizons, Georgia Tech\u0027s research magazine.\u003C\/strong\u003E\u003C\/em\u003E\u003Cstrong\u003E\u003C\/strong\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\n\u003C\/strong\u003E\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Vogel Robinson (404-385-3364)(\u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EGeorgia Tech has become a leader in developing epitaxial graphene, a material that can be grown on large wafers and patterned for use in electronics manufacturing. In a recent paper, Georgia Tech researchers reported fabricating an array of 10,000 top-gated transistors on a 0.24 square centimeter chip.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Georgia Tech has become a world leader in epitaxial graphene."}],"uid":"27303","created_gmt":"2011-01-06 01:00:00","changed_gmt":"2016-10-08 03:07:57","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2011-01-06T00:00:00-05:00","iso_date":"2011-01-06T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"63410":{"id":"63410","type":"image","title":"Producing epitaxial graphene","body":null,"created":"1449176690","gmt_created":"2015-12-03 21:04:50","changed":"1475894557","gmt_changed":"2016-10-08 02:42:37","alt":"Producing epitaxial graphene","file":{"fid":"191816","name":"tbs48688.jpg","image_path":"\/sites\/default\/files\/images\/tbs48688_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tbs48688_0.jpg","mime":"image\/jpeg","size":1202030,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tbs48688_0.jpg?itok=V_zWpccS"}},"63411":{"id":"63411","type":"image","title":"Professor Walt de Heer","body":null,"created":"1449176690","gmt_created":"2015-12-03 21:04:50","changed":"1475894557","gmt_changed":"2016-10-08 02:42:37","alt":"Professor Walt de Heer","file":{"fid":"191817","name":"tic48688.jpg","image_path":"\/sites\/default\/files\/images\/tic48688_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tic48688_0.jpg","mime":"image\/jpeg","size":1245665,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tic48688_0.jpg?itok=ZOUqWETF"}},"63412":{"id":"63412","type":"image","title":"Researcher Claire Berger","body":null,"created":"1449176690","gmt_created":"2015-12-03 21:04:50","changed":"1475894557","gmt_changed":"2016-10-08 02:42:37","alt":"Researcher Claire Berger","file":{"fid":"191818","name":"tcs48688.jpg","image_path":"\/sites\/default\/files\/images\/tcs48688_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tcs48688_0.jpg","mime":"image\/jpeg","size":1118539,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tcs48688_0.jpg?itok=26pfw7Do"}}},"media_ids":["63410","63411","63412"],"related_links":[{"url":"http:\/\/www.mrsec.gatech.edu\/","title":"Materials Research Science and Engineering Center"},{"url":"http:\/\/www.physics.gatech.edu\/","title":"Georgia Tech School of Physics"},{"url":"https:\/\/www.physics.gatech.edu\/user\/walter-de-heer","title":"Walt de Heer"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"153","name":"Computer Science\/Information Technology and Security"},{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"9826","name":"de Heer"},{"id":"9116","name":"epitaxial graphene"},{"id":"429","name":"graphene"},{"id":"9115","name":"MRSEC"},{"id":"960","name":"physics"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"62907":{"#nid":"62907","#data":{"type":"news","title":"Nobel prize committee under fire","body":[{"value":"\u003Cp\u003EA high-profile graphene researcher has written to the Nobel prize committee for physics, objecting to errors in its explanation of this year\u0027s prize. The award was given to Andre Geim and Konstantin Novoselov of Manchester University, UK, for their work on graphene, a two-dimensional carbon structure that has huge potential in the field of electronics.\u003C\/p\u003E\u003Cp\u003ENature article located at \u003Ca href=\u0022http:\/\/www.nature.com\/news\/2010\/101118\/full\/news.2010.620.html\u0022 title=\u0022http:\/\/www.nature.com\/news\/2010\/101118\/full\/news.2010.620.html\u0022\u003Ehttp:\/\/www.nature.com\/news\/2010\/101118\/full\/news.2010.620.html\u003C\/a\u003E\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Errors lead to accusations that committee did not do its homework before making the 2010 award for physics"}],"field_summary":[{"value":"\u003Cp\u003EA high-profile graphene researcher has written to the Nobel prize committee for physics, objecting to errors in its explanation of this year\u0027s prize. The award was given to Andre Geim and Konstantin Novoselov of Manchester University, UK, for their work on graphene, a two-dimensional carbon structure that has huge potential in the field of electronics.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":"","uid":"27428","created_gmt":"2010-11-22 15:05:55","changed_gmt":"2016-10-08 03:07:50","author":"Gina Adams","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-11-22T00:00:00-05:00","iso_date":"2010-11-22T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"groups":[{"id":"60783","name":"MRSEC"}],"categories":[],"keywords":[{"id":"429","name":"graphene"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}},"63022":{"#nid":"63022","#data":{"type":"news","title":"Georgia Tech\u2019s Walt de Heer Awarded Materials Research Society Medal","body":[{"value":"\u003Cp\u003EThe Materials Research Society awarded Walter A. de Heer,\nprofessor of physics at the Georgia Institute of Technology, the MRS Medal at\nits annual fall meeting in Boston today. De Heer was cited by the society for\nhis \u201cpioneering contributions to the science and technology of epitaxial\ngraphene.\u201d The MRS Medal recognizes an exceptional achievement in materials\nresearch in the past ten years. The MRS Medal is awarded for a\nspecific outstanding recent discovery or advancement that has a major impact on\nthe progress of a materials-related field.\u003C\/p\u003E\n\n\n\n\u003Cp\u003E\u201cI am very pleased and encouraged that our research to\ndevelop epi-graphene for electronics is recognized already in this early stage.\nThis will certainly stimulate others to join us in this important endeavor,\u201d\nsaid de Heer. \u003C\/p\u003E\n\n\n\n\u003Cp\u003EDe Heer and his lab at Georgia Tech are known worldwide as\nthe first to conceptualize the use of graphene for electronics, back in 2001.\nCurrently de Heer\u2019s lab is working on developing epitaxial graphene as a\nreplacement for silicon in electronics.\u003C\/p\u003E\n\n\n\n\u003Cp\u003E\u201cBecause epi-graphene may be able to surpass the speed\nlimitations of silicon, while also allowing for less heat to be generated in a\nsmaller chip, we believe that graphene shows great promise in being able to\nreplace silicon in electronics for applications such as ultra-high frequency\nelectronics, where these attributes will be needed most,\u201d said de Heer. \u003C\/p\u003E\n\n\n\n\u003Cp\u003E\u201cWalt de Heer is a\nglobal\u0026nbsp;leader in graphene research, and we congratulate him on this latest\nrecognition of his important work,\u201d said Georgia Tech President G.P. \u201cBud\u201d Peterson.\n\u0026nbsp;\u0026nbsp;\u201cThe interdisciplinary research that he and his colleagues are\ndoing at Georgia Tech has the potential to dramatically change the electronics\nindustry by enabling the use of this promising material in future generations\nof high-performance electronic devices.\u201d\u003C\/p\u003E\n\n\n\n\u003Cp\u003EDe Heer\nearned a doctoral degree in physics from the University of California - Berkeley\nin 1986. He worked at the \u00c9cole Polytechnique F\u00e9d\u00e9rale de Lausanne in\nSwitzerland from 1987-1997.\u003C\/p\u003E\n\n\n\n\u003Cp\u003ECurrently a\nRegents\u0027 Professor of Physics at the Tech, de Heer directs the \u003Ca href=\u0022http:\/\/www.physics.gatech.edu\/npeg\/\u0022\u003EEpitaxial\nGraphene Laboratory\u003C\/a\u003E in the School of Physics and leads the Epitaxial Graphene\nInterdisciplinary Research Group at the Georgia Tech \u003Ca href=\u0022http:\/\/www.mrsec.gatech.edu\/\u0022\u003EMaterials Research Science\nand Engineering Center\u003C\/a\u003E.\u003C\/p\u003E\n\n\n\n\u003Cp\u003EDe Heer and\nhis research groups have made significant contributions to several areas in\nnanoscopic physics. In 1995, de Heer\u2019s research turned to carbon nanotubes,\nshowing that they are excellent field emitters with potential application to\nflat panel displays. In 1998, he discovered that carbon nanotubes are ballistic\nconductors, which is a key property for graphene-based electronics. \u003C\/p\u003E\n\n\n\n\u003Cp\u003EIn 2001, his\nwork on nanopatterned epi-graphene electronics led to the development of\ngraphene-based electronics. This project was funded by Intel Corporation in 2003\nand by the National Science Foundation (NSF) in 2004. His paper, \u003Cem\u003EUltrathin\nEpitaxial Graphite: Two-Dimensional Electron Gas Properties and a Route Towards\nGraphene-Based Electronics\u003C\/em\u003E, published in the Journal of Physical Chemistry,\nlaid the experimental and conceptual foundation for graphene-based electronics.\nDe Heer holds the first patent for graphene-based electronics that was\nprovisionally filed in June 2003.\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"De Heer cited for pioneering contributions to the science and technology of epitaxial graphene."}],"field_summary":[{"value":"\u003Cp\u003EWalt de Heer awarded Materials Research Society Medal for \u201cpioneering contributions to the science and technology of epitaxial graphene.\u201d\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"De Heer cited for pioneering contributions to the science and technology of epitaxial graphene."}],"uid":"27310","created_gmt":"2010-12-02 09:10:14","changed_gmt":"2016-10-08 03:07:50","author":"David Terraso","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-12-02T00:00:00-05:00","iso_date":"2010-12-02T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"63023":{"id":"63023","type":"image","title":"Walt de Heer","body":null,"created":"1449176409","gmt_created":"2015-12-03 21:00:09","changed":"1475894549","gmt_changed":"2016-10-08 02:42:29","alt":"Walt de Heer","file":{"fid":"191703","name":"11C3031-P3-026.jpg","image_path":"\/sites\/default\/files\/images\/11C3031-P3-026.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/11C3031-P3-026.jpg","mime":"image\/jpeg","size":2600142,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/11C3031-P3-026.jpg?itok=6Lh_fwww"}}},"media_ids":["63023"],"related_links":[{"url":"http:\/\/www.physics.gatech.edu\/","title":"Georgia Tech School of Physics"},{"url":"http:\/\/www.physics.gatech.edu\/npeg\/","title":"Epitaxial Graphene Lab"},{"url":"http:\/\/www.mrsec.gatech.edu\/","title":"Materials Research Science and Engineering Center"}],"groups":[{"id":"1183","name":"Home"}],"categories":[{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"9826","name":"de Heer"},{"id":"10880","name":"epitaxial"},{"id":"429","name":"graphene"},{"id":"11375","name":"materials research society"},{"id":"1693","name":"MRS"},{"id":"11374","name":"walt"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EGeorgia Tech Media Relations\u003C\/strong\u003E\u003Cbr \/\u003ELaura Diamond\u003Cbr \/\u003E\u003Ca href=\u0022mailto:laura.diamond@comm.gatech.edu\u0022\u003Elaura.diamond@comm.gatech.edu\u003C\/a\u003E\u003Cbr \/\u003E404-894-6016\u003Cbr \/\u003EJason Maderer\u003Cbr \/\u003E\u003Ca href=\u0022mailto:maderer@gatech.edu\u0022\u003Emaderer@gatech.edu\u003C\/a\u003E\u003Cbr \/\u003E404-660-2926\u003C\/p\u003E","format":"limited_html"}],"email":["david.terraso@comm.gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"62422":{"#nid":"62422","#data":{"type":"news","title":"Templates let graphene grow","body":[{"value":"\u003Cp\u003E\u003Ca title=\u0022Templates let graphene grow\u0022 href=\u0022http:\/\/www.futurity.org\/science-technology\/templates-let-graphene-grow\/\u0022\u003EWhile successful fabrication of high-quality transistors demonstrates graphene\u0027s viability as an electronic material, Walt de Heer sees them as only the first step in what could be done with the material. Pictured above is a graphene transistor.\u003C\/a\u003E\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Templates let graphene grow"}],"field_summary":[{"value":"\u003Cp\u003E\u003Ca title=\u0022Templates let graphene grow\u0022 href=\u0022http:\/\/www.futurity.org\/science-technology\/templates-let-graphene-grow\/\u0022\u003EWhile successful fabrication of high-quality transistors demonstrates graphene\u0027s viability as an electronic material, Walt de Heer sees them as only the first step in what could be done with the material. Pictured above is a graphene transistor.\u003C\/a\u003E\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"While successful fabrication of high-quality transistors demonstrates graphene\u0027s viability as an electronic material, Walt de Heer sees them as only the first step in what could be done with the material. Pictured above is a graphene transistor."}],"uid":"27428","created_gmt":"2010-10-29 16:27:56","changed_gmt":"2016-10-08 03:07:42","author":"Gina Adams","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-10-29T00:00:00-04:00","iso_date":"2010-10-29T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"63027":{"id":"63027","type":"image","title":"Templates let graphene grow","body":null,"created":"1449176409","gmt_created":"2015-12-03 21:00:09","changed":"1475894549","gmt_changed":"2016-10-08 02:42:29","alt":"Templates let graphene grow","file":{"fid":"191705","name":"nnano_2010_192-f8.jpg","image_path":"\/sites\/default\/files\/images\/nnano_2010_192-f8_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/nnano_2010_192-f8_0.jpg","mime":"image\/jpeg","size":86735,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/nnano_2010_192-f8_0.jpg?itok=mB7c5mlX"}}},"media_ids":["63027"],"groups":[{"id":"60783","name":"MRSEC"}],"categories":[{"id":"149","name":"Nanotechnology and Nanoscience"}],"keywords":[{"id":"429","name":"graphene"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}},"62364":{"#nid":"62364","#data":{"type":"news","title":"Beyond the Nobel Prize, What\u2019s Next for Graphene?","body":[{"value":"\u003Cp\u003EIf you had never heard of \u201cgraphene\u201d before, you might know something about it now \u2013 if you follow the Nobel Prize announcements. Two physicists were awarded the Nobel Prize in Physics \u0022for groundbreaking experiments regarding the two-dimensional material graphene,\u0022 carbon flakes that are only as thick as a single atom yet as strong as steel and as conductive as copper. But, what happens next for this revolutionary nanoscale material? Two social scientists began a study earlier in 2010 to understand the as yet undeveloped pathway to the commercialization of graphene \u2013 the processes, plans, promises and perils. Team leaders with the Center for Nanotechnology in Society at Arizona State University (CNS-ASU), Jan Youtie at Georgia Institute of Technology (Georgia Tech) and Philip Shapira at the University of Manchester and Georgia Tech are in the throes of their project on the Comparative Research and Innovation Approaches of Graphene Centers.\u003C\/p\u003E\u003Cp\u003EGraphene is anticipated to have potential applications in electronics to build semiconductors beyond the limits of silicon-based technology. It also offers promising applications for higher performance solar cells, LCD screens and photon sensors. Now that graphene has been identified and found to be stable in ultra-thin sheets, research efforts to understand it more thoroughly and to produce it in large quantities have ballooned. Yet, graphene is still at the development stage, and its commercialization pathway remains to be determined.\u003C\/p\u003E\u003Cp\u003ETo kick-off their work on graphene innovation, Youtie and Shapira have been undertaking field work in two of the world\u2019s leading centers for graphene development: the University of Manchester and Georgia Tech. As acknowledged by the Nobel Committee for Physics when it awarded its 2010 Prize to Manchester physicists Andre Geim and Konstantin Novoselov, Manchester is the site of seminal work on graphene, including the first laboratory production of graphene sheets. Georgia Tech is the site of a National Science Foundation-funded Materials Science and Engineering Center (MRSEC) focused on research and development on epitaxial graphene. Youtie\u2019s and Shapira\u2019s project seeks to understand similarities and differences in the plans, programs and approaches to commercialize graphene-related applications in both locations. This includes examination of both the strategies for research and development and those for fostering commercialization in terms of external partnerships in the metropolitan regions of Manchester and Atlanta, elsewhere in the country, and internationally. In addition to field work, Youtie and Shapira also are undertaking analyses of publications, patents, funding, and corporate activities in graphene.\u003C\/p\u003E\u003Cp\u003EOver the coming year, Youtie and Shapira plan to expand their research focus to other locations in the United States and around the world where graphene research and commercialization clusters are emerging. Although graphene\u2019s full impacts may take many years to materialize, the results of Youtie\u2019s and Shapira\u2019s research will provide real-time insights to researchers, companies, policymakers and other stakeholders keen to understand how research in specific nanotechnology domains moves into early applications, what barriers and concerns are raised, and how these are being addressed.\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EYoutie\u2019s and Shapira\u0027s pilot project has received travel funding from a UK-US Collaboration Development Award (CDA) of the British Embassy and British Consulates in the United States, with supplementary support through CNS-ASU and the Manchester Institute for Innovation Research.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis article is from Scientific Computing\u003C\/em\u003E\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Researchers seek to understand similarities and differences in the plans, programs and approaches to commercialize graphene."}],"field_summary":[{"value":"\u003Cp\u003ETwo social scientists began a study earlier in 2010 to understand the as yet undeveloped pathway to the commercialization of graphene \u2013 the processes, plans, promises and perils. Team leaders with the Center for Nanotechnology in Society at Arizona State University (CNS-ASU), Jan Youtie at Georgia Institute of Technology (Georgia Tech) and Philip Shapira at the University of Manchester and Georgia Tech are in the throes of their project on the Comparative Research and Innovation Approaches of Graphene Centers.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":"","uid":"27167","created_gmt":"2010-10-26 16:28:26","changed_gmt":"2016-10-08 03:07:38","author":"Rebecca Keane","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-10-18T00:00:00-04:00","iso_date":"2010-10-18T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"62365":{"id":"62365","type":"image","title":"Philip Shapira, Professor, School of Public Policy","body":null,"created":"1449176369","gmt_created":"2015-12-03 20:59:29","changed":"1475894541","gmt_changed":"2016-10-08 02:42:21","alt":"Philip Shapira, Professor, School of Public Policy","file":{"fid":"191455","name":"Phil_Shapira_200x300.jpg","image_path":"\/sites\/default\/files\/images\/Phil_Shapira_200x300_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/Phil_Shapira_200x300_0.jpg","mime":"image\/jpeg","size":32576,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/Phil_Shapira_200x300_0.jpg?itok=xPGA87bk"}},"62508":{"id":"62508","type":"image","title":"Jan Youtie","body":null,"created":"1449176369","gmt_created":"2015-12-03 20:59:29","changed":"1475894541","gmt_changed":"2016-10-08 02:42:21","alt":"Jan Youtie","file":{"fid":"191481","name":"Jan_Youtie_300x200.jpg","image_path":"\/sites\/default\/files\/images\/Jan_Youtie_300x200_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/Jan_Youtie_300x200_0.jpg","mime":"image\/jpeg","size":32580,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/Jan_Youtie_300x200_0.jpg?itok=Y7XGmFCR"}}},"media_ids":["62365","62508"],"related_links":[{"url":"http:\/\/www.scientificcomputing.com\/news-DS-Beyond-the-Nobel-Prize-Whats-Next-for-Graphene-101810.aspx","title":"Article"}],"groups":[{"id":"1281","name":"Ivan Allen College of Liberal Arts"}],"categories":[],"keywords":[{"id":"2579","name":"commercialization"},{"id":"429","name":"graphene"},{"id":"171037","name":"Shapira"},{"id":"11066","name":"Youtie"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003ERebecca Keane\u0026nbsp; 404-894-1720\u003C\/p\u003E","format":"limited_html"}],"email":["rebecca.keane@iac.gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"61435":{"#nid":"61435","#data":{"type":"news","title":"New Graphene Fabrication Method Uses Silicon Carbide Template","body":[{"value":"\u003Cp\u003EResearchers at the Georgia Institute of Technology have developed a new \u201ctemplated growth\u201d technique for fabricating nanometer-scale graphene devices.  The method addresses what had been a significant obstacle to the use of this promising material in future generations of high-performance electronic devices.\u003C\/p\u003E\n\u003Cp\u003EThe technique involves etching patterns into the silicon carbide surfaces on which epitaxial graphene is grown.  The patterns serve as templates directing the growth of graphene structures, allowing the formation of nanoribbons of specific widths without the use of e-beams or other destructive cutting techniques.  Graphene nanoribbons produced with these templates have smooth edges that avoid electron-scattering problems.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Using this approach, we can make very narrow ribbons of interconnected graphene without the rough edges,\u0022 said Walt de Heer, a professor in the Georgia Tech School of Physics.  \u0022Anything that can be done to make small structures without having to cut them is going to be useful to the development of graphene electronics because if the edges are too rough, electrons passing through the ribbons scatter against the edges and reduce the desirable properties of graphene.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe new technique has been used to fabricate an array of 10,000 top-gated graphene transistors on a 0.24 square centimeter chip \u2013 believed to be the largest density of graphene devices reported so far.\n\u003C\/p\u003E\n\u003Cp\u003EThe research was reported Oct. 3 in the advance online edition of the journal \u003Cem\u003ENature Nanotechnology\u003C\/em\u003E.  The work was supported by the National Science Foundation, the W.M. Keck Foundation and the Nanoelectronics Research Initiative Institute for Nanoelectronics Discovery and Exploration (INDEX).\n\u003C\/p\u003E\n\u003Cp\u003EIn creating their graphene nanostructures, De Heer and his research team first use conventional microelectronics techniques to etch tiny \u0022steps\u0022 \u2013 or contours \u2013 into a silicon carbide wafer.  They then heat the contoured wafer to approximately 1,500 degrees Celsius, which initiates melting that polishes any rough edges left by the etching process.\n\u003C\/p\u003E\n\u003Cp\u003EThey then use established techniques for growing graphene from silicon carbide by driving off the silicon atoms from the surface.  Instead of producing a consistent layer of graphene one atom thick across the surface of the wafer, however, the researchers limit the heating time so that graphene grows only on the edges of the contours.\n\u003C\/p\u003E\n\u003Cp\u003ETo do this, they take advantage of the fact that graphene grows more rapidly on certain facets of the silicon carbide crystal than on others.  The width of the resulting nanoribbons is proportional to the depth of the contour, providing a mechanism for precisely controlling the nanoribbons.  To form complex graphene structures, multiple etching steps can be carried out to create a complex template, de Heer explained.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022By using the silicon carbide to provide the template, we can grow graphene in exactly the sizes and shapes that we want,\u0022 he said. \u0022Cutting steps of various depths allows us to create graphene structures that are interconnected in the way we want them to be.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EIn nanometer-scale graphene ribbons, quantum confinement makes the material behave as a semiconductor suitable for creation of electronic devices.  But in ribbons a micron or more wide, the material acts as a conductor.  Controlling the depth of the silicon carbide template allows the researchers to create these different structures simultaneously, using the same growth process.  \n\u003C\/p\u003E\n\u003Cp\u003E\u0022The same material can be either a conductor or a semiconductor depending on its shape,\u0022 noted de Heer, who is also a faculty member in Georgia Tech\u2019s National Science Foundation-supported Materials Research Science and Engineering Center (MRSEC).  \u0022One of the major advantages of graphene electronics is to make the device leads and the semiconducting ribbons from the same material.  That\u0027s important to avoid electrical resistance that builds up at junctions between different materials.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EAfter formation of the nanoribbons \u2013 which can be as narrow as 40 nanometers \u2013 the researchers apply a dielectric material and metal gate to construct field-effect transistors.  While successful fabrication of high-quality transistors demonstrates graphene\u0027s viability as an electronic material, de Heer sees them as only the first step in what could be done with the material.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022When we manage to make devices well on the nanoscale, we can then move on to make much smaller and finer structures that will go beyond conventional transistors to open up the possibility for more sophisticated devices that use electrons more like light than particles,\u0022 he said.  \u0022If we can factor quantum mechanical features into electronics, that is going to open up a lot of new possibilities.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EDe Heer and his research team are now working to create smaller structures, and to integrate the graphene devices with silicon.  The researchers are also working to improve the field-effect transistors with thinner dielectric materials.\n\u003C\/p\u003E\n\u003Cp\u003EUltimately, graphene may be the basis for a generation of high-performance devices that will take advantage of the material\u0027s unique properties in applications where the higher cost can be justified.  Silicon will continue to be used in applications that don\u0027t require such high performance, de Heer said.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022This is another step showing that our method of working with epitaxial graphene on silicon carbide is the right approach and the one that will probably be used for making graphene electronics,\u0022 he added.  \u0022This is a significant new step toward electronics manufacturing with graphene.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EIn addition to those already mentioned, the research has involved M. Sprinkle, M. Ruan, Y Hu, J. Hankinson, M. Rubio-Roy, B. Zhang, X. Wu and C. Berger.\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\u003C\/strong\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Vogel Robinson (404-385-3364)(\u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\n\u003C\/p\u003E\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EGeorgia Tech researchers have developed a new \u0022templated growth\u0022 technique for fabricating nanometer-scale graphene devices.  The method addresses what had been a significant obstacle to the use of this promising material in future generations of high-performance electronic devices.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"A new template approach is being used to fabricate graphene devi"}],"uid":"27303","created_gmt":"2010-10-05 00:00:00","changed_gmt":"2016-10-08 03:07:34","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-10-05T00:00:00-04:00","iso_date":"2010-10-05T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"61436":{"id":"61436","type":"image","title":"Graphene transistors","body":null,"created":"1449176337","gmt_created":"2015-12-03 20:58:57","changed":"1475894536","gmt_changed":"2016-10-08 02:42:16","alt":"Graphene transistors","file":{"fid":"191358","name":"tcv90049.jpg","image_path":"\/sites\/default\/files\/images\/tcv90049_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tcv90049_0.jpg","mime":"image\/jpeg","size":535060,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tcv90049_0.jpg?itok=IZZUcHgA"}},"61437":{"id":"61437","type":"image","title":"Graphene nanoribbon","body":null,"created":"1449176337","gmt_created":"2015-12-03 20:58:57","changed":"1475894536","gmt_changed":"2016-10-08 02:42:16","alt":"Graphene nanoribbon","file":{"fid":"191359","name":"trf90049.jpg","image_path":"\/sites\/default\/files\/images\/trf90049_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/trf90049_0.jpg","mime":"image\/jpeg","size":609209,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/trf90049_0.jpg?itok=I30e2Uoy"}}},"media_ids":["61436","61437"],"related_links":[{"url":"http:\/\/www.physics.gatech.edu\/","title":"Georgia Tech School of Physics"},{"url":"http:\/\/www.physics.gatech.edu\/people\/faculty\/wdeheer.html","title":"Walt de Heer"},{"url":"http:\/\/mrsec.gatech.edu\/","title":"Materials Research Science and Engineering Center (MRSEC)"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"141","name":"Chemistry and Chemical Engineering"},{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"1928","name":"devices"},{"id":"4264","name":"fabrication"},{"id":"429","name":"graphene"},{"id":"10851","name":"template"},{"id":"7528","name":"transistors"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"61514":{"#nid":"61514","#data":{"type":"news","title":"Researchers Develop Techniques for Using Material Recognized in Nobel Prize","body":[{"value":"\u003Cp\u003EGeorgia Institute of Technology researchers have pioneered the fabrication techniques expected to be used for manufacturing high-performance electronic devices from the material that has been recognized in this year\u0027s Nobel Prize in physics. \u003C\/p\u003E\u003Cp\u003EThe 2010 physics prize was awarded for producing, isolating, identifying and characterizing graphene, a single atomic layer of carbon whose unique properties make the material attractive for electronic applications. Scientists at the University of Manchester were recognized for their work on graphene sheets peeled from blocks of graphite. \u003C\/p\u003E\u003Cp\u003EThe work of the Georgia Tech group, headed by Professor Walt de Heer in the Georgia Tech School of Physics, was recognized by the Royal Swedish Academy of Sciences in its scientific background document on the physics prize. De Heer\u0027s group pioneered epitaxial techniques for growing large-scale graphene sheets by heating wafers of silicon carbide to drive off the silicon, leaving a thin layer of graphene. \u003C\/p\u003E\u003Cp\u003EThe technique, which is now being used by research groups at companies such as IBM, has practical applications in large-scale production of electronic devices. On Oct. 3, the group published a paper in the journal \u003Cem\u003ENature Nanotechnology\u003C\/em\u003E describing a new technique used to produce an array of 10,000 graphene transistors. \u003C\/p\u003E\u003Cp\u003E\u0022We believe that our technique, or one very much like it, will ultimately be used to manufacture future generations of graphene-based electronic devices,\u0022 said de Heer. \u0022Using techniques that are suitable for scaling up for mass production, we can grow graphene in the patterns that we need for electronic devices.\u0022 \u003C\/p\u003E\u003Cp\u003EThe Georgia Tech group holds a patent, filed in 2003, on fabricating electronic devices from these graphene layers. \u003C\/p\u003E\u003Cp\u003EGeorgia Tech is home to a Materials Research Science and Engineering Center (MRSEC), funded by the National Science Foundation (NSF) and including collaborators from the University of California-Berkeley, University of California-Riverside and University of Michigan. The foundation focus of the center is research and development of epitaxial graphene. \u003C\/p\u003E\u003Cp\u003E\u0022The unique properties of graphene portend considerable promise for future electronic and optical devices,\u0022 said Dennis Hess, the center\u0027s director. \u0022If graphene is to serve as a viable successor to silicon-based microelectronic devices and circuits, large scale production on a suitable substrate is required. Proof of concept of this approach has already been demonstrated by the fabrication of a 10,000 epitaxial graphene transistor array by Walt de Heer and his collaborators. This achievement is a significant advance toward realizing carbon-based electronics for the 21st century.\u0022 \u003C\/p\u003E\u003Cp\u003EThe Georgia Tech team also collaborates with researchers at the National Institute of Standards and Technology (NIST) on characterizing the unique properties of graphene. That work has led to several recent important papers, in journals such as \u003Cem\u003EScience\u003C\/em\u003E and \u003Cem\u003ENature Physics\u003C\/em\u003E. The latter described for the first time how the orbits of electrons are distributed spatially by magnetic fields applied to layers of epitaxial graphene. \u003C\/p\u003E\u003Cp\u003EOn Oct. 3 in the advance online publication of the journal \u003Cem\u003ENature Nanotechnology\u003C\/em\u003E, de Heer and collaborators described the development of a new \u0022templated growth\u0022 technique for fabricating nanometer-scale graphene devices. The method addresses what had been a significant obstacle to the use of this promising material in future generations of high-performance electronic devices. \u003C\/p\u003E\u003Cp\u003EThe technique involves etching patterns into the silicon carbide surfaces on which epitaxial graphene is grown. The patterns serve as templates directing the growth of graphene structures, allowing the formation of nanoribbons of specific widths without the use of e-beams or other destructive cutting techniques. Templated nanoribbon growth addresses the edge roughness that causes electron scattering. \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003EGeorgia Institute of Technology\u003Cbr \/\u003E75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003EAtlanta, Georgia 30308 USA\u003C\/strong\u003E \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Vogel Robinson (404-385-3364)(\u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E). \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon \u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EGeorgia Institute of Technology researchers have pioneered the fabrication techniques expected to be used for manufacturing high-performance electronic devices from the material that has been recognized in this year\u0027s Nobel Prize in physics.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Georgia Tech researchers were cited by Nobel Prize committee."}],"uid":"27303","created_gmt":"2010-10-07 00:00:00","changed_gmt":"2016-10-08 03:07:34","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-10-07T00:00:00-04:00","iso_date":"2010-10-07T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"61515":{"id":"61515","type":"image","title":"Walt de Heer in laboratory","body":null,"created":"1449176337","gmt_created":"2015-12-03 20:58:57","changed":"1475894536","gmt_changed":"2016-10-08 02:42:16","alt":"Walt de Heer in laboratory","file":{"fid":"191374","name":"tty62482.jpg","image_path":"\/sites\/default\/files\/images\/tty62482_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tty62482_0.jpg","mime":"image\/jpeg","size":1471812,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tty62482_0.jpg?itok=oZs1YRmK"}}},"media_ids":["61515"],"related_links":[{"url":"http:\/\/www.physics.gatech.edu\/","title":"Georgia Tech School of Physics"},{"url":"http:\/\/www.physics.gatech.edu\/people\/faculty\/wdeheer.html","title":"Walt de Heer"},{"url":"http:\/\/mrsec.gatech.edu\/","title":"Materials Research Science and Engineering Center (MRSEC)"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"141","name":"Chemistry and Chemical Engineering"},{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"1928","name":"devices"},{"id":"609","name":"electronics"},{"id":"10880","name":"epitaxial"},{"id":"429","name":"graphene"},{"id":"7435","name":"material"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"60861":{"#nid":"60861","#data":{"type":"news","title":"Instrument Reveals Quartet of Graphene Electron States","body":[{"value":"\u003Cp\u003EUsing a one-of-a-kind instrument designed and built at the National Institute of Standards and Technology (NIST), researchers have \u0022unveiled\u0022 a quartet of graphene\u0027s electron states and discovered that electrons in graphene can split up into an unexpected and tantalizing set of energy levels when exposed to extremely low temperatures and extremely high magnetic fields. \u003C\/p\u003E\u003Cp\u003EReported Sept. 9 in the journal \u003Cem\u003ENature\u003C\/em\u003E, the new research raises several intriguing questions about the fundamental physics of this exciting material and reveals new effects that may make graphene even more powerful than previously expected for practical applications. \u003C\/p\u003E\u003Cp\u003ELed by NIST Fellow Joseph Stroscio, the research team included scientists from the Georgia Institute of Technology, the University of Maryland, Seoul National University, and the University of Texas at Austin. \u003C\/p\u003E\u003Cp\u003EGraphene is one of the simplest materials -- a single-atom-thick sheet of carbon atoms arranged in a honeycomb-like lattice -- yet it has many remarkable and surprisingly complex properties. Measuring and understanding how electrons carry current through the sheet is a key to achieving its technological promise in wide-ranging applications, including high speed electronics and sensors. \u003C\/p\u003E\u003Cp\u003EFor example, the electrons in graphene act as if they have no mass and are almost 100 times more mobile than in silicon. Moreover, the speed with which electrons move through graphene is not related to their energy, unlike materials such as silicon where more voltage must be applied to increase their speed, which creates heat that is detrimental to most applications. \u003C\/p\u003E\u003Cp\u003ETo fully understand the behavior of graphene\u0027s electrons, scientists must study the material under an extreme environment of ultra-high vacuum, ultra-low temperatures, and large magnetic fields. Under these conditions, the graphene sheet remains pristine for weeks. \u003C\/p\u003E\u003Cp\u003ENIST has recently constructed the world\u2019s most powerful and stable scanning-probe microscope, with an unprecedented combination of low temperature (as low as 10 millikelvin, or 10 thousandths of a degree above absolute zero), ultra-high vacuum, and high magnetic field. In the first measurements made with this instrument, the international team has used its power to resolve the finest differences in the electron energies in graphene, atom-by-atom. \u003C\/p\u003E\u003Cp\u003E\u0022Going to this resolution allows you to see new physics,\u0022 said Young Jae Song, a postdoctoral researcher who helped develop the instrument at NIST and make these first measurements. \u003C\/p\u003E\u003Cp\u003EAnd the new physics the team saw raises a few more questions about how the electrons behave in graphene than it answers. \u003C\/p\u003E\u003Cp\u003EBecause of the geometry and electromagnetic properties of graphene\u0027s structure, an electron in any given energy level populates four possible sublevels, called a \u0022quartet.\u0022 Theorists have predicted that this quartet of levels would split into different energies when immersed in a magnetic field, but until recently there had not been an instrument sensitive enough to resolve these differences. \u003C\/p\u003E\u003Cp\u003E\u0022When we increased the magnetic field at extreme low temperatures, we observed unexpectedly complex quantum behavior of the electrons,\u0022 said NIST Fellow Joseph Stroscio. \u003C\/p\u003E\u003Cp\u003EWhat is happening, according to Stroscio, appears to be a \u0022many-body effect\u0022 in which electrons interact strongly with one another in ways that affect their energy levels. \u003C\/p\u003E\u003Cp\u003EOne possible explanation for this behavior is that the electrons have formed a \u0022condensate\u0022 in which they cease moving independently of one another and act as a single coordinated unit. \u003C\/p\u003E\u003Cp\u003EThe new experiments also showed surprising stability in the quartet states, an issue that warrants further study, said Phillip First, a professor in Georgia Tech\u0027s School of Physics and one of the study\u0027s co-authors. \u003C\/p\u003E\u003Cp\u003E\u0022The experiment shows that these magnetic configurations become especially stable when any one of the quartet states is completely filled with electrons, which indicates the importance of many-body correlations,\u0022 he said. \u0022However, the most surprising thing is the observation of new stable states that occur when a quartet state is exactly half filled. That\u0027s pretty remarkable, and we still need an explanation.\u0022 \u003C\/p\u003E\u003Cp\u003EGraphene has attracted strong interest as a potential material for future electronic devices, and this new work reinforces that expectation. \u003C\/p\u003E\u003Cp\u003E\u0022If our hypothesis proves to be correct, it could point the way to the creation of smaller, very-low-heat producing, highly energy efficient electronic devices based upon graphene,\u0022 said Shaffique Adam, a postdoctoral researcher who assisted with theoretical analysis of the measurements. \u003C\/p\u003E\u003Cp\u003EIn addition to First, Georgia Tech researchers contributing to the paper included Walt de Heer, Yike Hu and David Torrance. The research was supported in part by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD)(KRF-2006-214-C00022), the National Science Foundation (DMR-0820382 [MRSEC], DMR-0804908, DMR-0606489), the Welch Foundation and the Semiconductor Research Corporation (NRI-INDEX program). \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003EGeorgia Institute of Technology\u003Cbr \/\u003E75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003EAtlanta, Georgia 30308 USA\u003C\/strong\u003E \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: Mark Esser, NIST, (301-975-8735)(\u003Ca href=\u0022mailto:mark.esser@nist.gov\u0022\u003Emark.esser@nist.gov\u003C\/a\u003E) or John Toon, Georgia Tech, (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E). \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: Mark Esser \u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EUsing a one-of-a-kind instrument designed and built at the National Institute of Standards and Technology (NIST), researchers have \u0022unveiled\u0022 a quartet of graphene\u0027s electron states and discovered that electrons in graphene can split up into an unexpected and tantalizing set of energy levels when exposed to extremely low temperatures and extremely high magnetic fields.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Research yields new information on graphene\u0027s electron states."}],"uid":"27303","created_gmt":"2010-09-07 00:00:00","changed_gmt":"2016-10-08 03:07:23","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-09-07T00:00:00-04:00","iso_date":"2010-09-07T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"60862":{"id":"60862","type":"image","title":"NIST scanning probe microscope","body":null,"created":"1449176296","gmt_created":"2015-12-03 20:58:16","changed":"1475894528","gmt_changed":"2016-10-08 02:42:08","alt":"NIST scanning probe microscope","file":{"fid":"191227","name":"trm09953.jpg","image_path":"\/sites\/default\/files\/images\/trm09953_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/trm09953_0.jpg","mime":"image\/jpeg","size":1261222,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/trm09953_0.jpg?itok=0h08uyMH"}}},"media_ids":["60862"],"related_links":[{"url":"http:\/\/www.mrsec.gatech.edu\/","title":"Materials Research Science and Engineering Center"},{"url":"http:\/\/www.physics.gatech.edu\/","title":"Georgia Tech School of Physics"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"10597","name":"electron state"},{"id":"10599","name":"energy level"},{"id":"429","name":"graphene"},{"id":"10598","name":"NIST"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"60893":{"#nid":"60893","#data":{"type":"news","title":"Scientists Gather for Symposium on Epitaxial Graphene","body":[{"value":"\u003Cp\u003EScientists from around the world will gather next week to\ndiscuss the latest research findings at the second International\nSymposium on the Science and Technology of Epitaxial Graphene. The conference\nis sponsored by the Materials Research Science and Engineering Center at the\nGeorgia Institute of Technology. It will take place September 14-17, 2010, at\nthe Hampton Inn \u0026amp; Suites Amelia Island Historic Harbor Front Hotel in\nAmelia Island, Florida. \u003C\/p\u003E\n\n\n\n\u003Cp\u003E\u201cThe symposium brings together engineers and scientists from\naround the world to discuss recent progress and future trends in the rapidly\ndeveloping science and technology of epitaxial graphene,\u201d said Walt de Heer,\nRegents\u2019 Professor in Georgia Tech\u2019s School\nof Physics and a pioneer in graphene-based electronics. \u201cThe symposium will\ncover a broad range of epitaxial graphene on silicon carbide\ntopics,\u0026nbsp;including surface science and growth, transport, optical\nproperties, chemistry, devices and\ntheory.\u0026nbsp; The discussions during this symposium will help to establish the\nfuture directions of epitaxial graphene science and technology.\u201d\u003C\/p\u003E\n\n\n\n\u003Cp\u003EThe symposium was first held in 2009 and is expected to be a\nyearly gathering. This year 130 attendees are expected. In addition to scientists\nfrom Georgia Tech, researchers from institutions such as the University of\nCalifornia, the National Institute of Standards and Technology, \u0026nbsp;the French National Center for\nScientific Research (CNRS), the German Max Planck Institute, the Japanese NTT\nlabs\u0026nbsp; and\u0026nbsp; several representatives from industry will be in attendance.\n\u003C\/p\u003E\n\n\n\n\u003Cp\u003ESo far, the substance has shown great promise in being a\nmaterial that can conduct electricity with little resistance without many of\nthe problems that carbon nanotubes have exhibited, such as difficulties with\nplacing them and building them into wires. In addition, research suggests that\nepitaxial graphene may offer much greater speed and performance over silicon.\u003C\/p\u003E\n\n\u003Cp\u003EScientists at the symposium will discuss the recent results\nof their research and will likely plan future scientific endeavors in this\nfield. \u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EScientists from around the world will gather next week to\ndiscuss the latest research findings at the second International Symposium on\nthe Science and Technology of Epitaxial Graphene. The conference is sponsored by\nthe Materials Research Science and Engineering Center at the Georgia Institute\nof Technology. It will take place September 14-17, 2010, at the Hampton Inn\n\u0026amp; Suites Amelia Island Historic Harbor Front Hotel in Amelia Island,\nFlorida. \u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Symposium takes place at Amelia Island September 14-17."}],"uid":"27310","created_gmt":"2010-09-10 08:21:29","changed_gmt":"2016-10-08 03:07:23","author":"David Terraso","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-09-10T00:00:00-04:00","iso_date":"2010-09-10T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"61437":{"id":"61437","type":"image","title":"Graphene nanoribbon","body":null,"created":"1449176337","gmt_created":"2015-12-03 20:58:57","changed":"1475894536","gmt_changed":"2016-10-08 02:42:16","alt":"Graphene nanoribbon","file":{"fid":"191359","name":"trf90049.jpg","image_path":"\/sites\/default\/files\/images\/trf90049_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/trf90049_0.jpg","mime":"image\/jpeg","size":609209,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/trf90049_0.jpg?itok=I30e2Uoy"}}},"media_ids":["61437"],"groups":[{"id":"1183","name":"Home"}],"categories":[{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"10615","name":"deHeer"},{"id":"429","name":"graphene"},{"id":"960","name":"physics"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EGeorgia Tech Media Relations\u003C\/strong\u003E\u003Cbr \/\u003ELaura Diamond\u003Cbr \/\u003E\u003Ca href=\u0022mailto:laura.diamond@comm.gatech.edu\u0022\u003Elaura.diamond@comm.gatech.edu\u003C\/a\u003E\u003Cbr \/\u003E404-894-6016\u003Cbr \/\u003EJason Maderer\u003Cbr \/\u003E\u003Ca href=\u0022mailto:maderer@gatech.edu\u0022\u003Emaderer@gatech.edu\u003C\/a\u003E\u003Cbr \/\u003E404-660-2926\u003C\/p\u003E","format":"limited_html"}],"email":["david.terraso@comm.gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"60372":{"#nid":"60372","#data":{"type":"news","title":"Study of Electron Orbits in Multilayer Graphene Finds Energy Gaps","body":[{"value":"\u003Cp\u003EResearchers have taken one more step toward understanding the unique and often unexpected properties of graphene, a two-dimensional carbon material that has attracted interest because of its potential applications in future generations of electronic devices.\u003C\/p\u003E\u003Cp\u003EIn the Aug. 8 advance online edition of the journal \u003Cem\u003ENature Physics\u003C\/em\u003E, researchers from the Georgia Institute of Technology and the National Institute of Standards and Technology (NIST) describe for the first time how the orbits of electrons are distributed spatially by magnetic fields applied to layers of epitaxial graphene. \u003C\/p\u003E\u003Cp\u003EThe research team also found that these electron orbits can interact with the substrate on which the graphene is grown, creating energy gaps that affect how electron waves move through the multilayer material. These energy gaps could have implications for the designers of certain graphene-based electronic devices. \u003C\/p\u003E\u003Cp\u003E\u0022The regular pattern of energy gaps in the graphene surface creates regions where electron transport is not allowed,\u0022 said Phillip N. First, a professor in the Georgia Tech School of Physics and one of the paper\u2019s co-authors. \u0022Electron waves would have to go around these regions, requiring new patterns of electron wave interference. Understanding such interference will be important for bi-layer graphene devices that have been proposed, and may be important for other lattice-matched substrates used to support graphene and graphene devices.\u0022 \u003C\/p\u003E\u003Cp\u003EIn a magnetic field, an electron moves in a circular trajectory -- known as a cyclotron orbit -- whose radius depends on the size of the magnetic field and the energy of electron. For a constant magnetic field, that\u0027s a little like rolling a marble around in a large bowl, First said. \u003C\/p\u003E\u003Cp\u003E\u0022At high energy, the marble orbits high in the bowl, while for lower energies, the orbit size is smaller and lower in the bowl,\u0022 he explained. \u0022The cyclotron orbits in graphene also depend on the electron energy and the local electron potential -- corresponding to the bowl -- but until now, the orbits hadn\u2019t been imaged directly.\u0022 \u003C\/p\u003E\u003Cp\u003EPlaced in a magnetic field, these orbits normally drift along lines of nearly constant electric potential. But when a graphene sample has small fluctuations in the potential, these \u0022drift states\u0022 can become trapped at a hill or valley in the material that has closed constant potential contours. Such trapping of charge carriers is important for the quantum Hall effect, in which precisely quantized resistance results from charge conduction solely through the orbits that skip along the edges of the material. \u003C\/p\u003E\u003Cp\u003EThe study focused on one particular electron orbit: a zero-energy orbit that is unique to graphene. Because electrons are matter waves, interference within a material affects how their energy relates to the velocity of the wave -- and reflected waves added to an incoming wave can combine to produce a slower composite wave. Electrons moving through the unique \u0022chicken-wire\u0022 arrangement of carbon-carbon bonds in the graphene interfere in a way that leaves the wave velocity the same for all energy levels. \u003C\/p\u003E\u003Cp\u003EIn addition to finding that energy states follow contours of constant electric potential, the researchers discovered specific areas on the graphene surface where the orbital energy of the electrons changes from one atom to the next. That creates an energy gap within isolated patches on the surface. \u003C\/p\u003E\u003Cp\u003E\u0022By examining their distribution over the surface for different magnetic fields, we determined that the energy gap is due to a subtle interaction with the substrate, which consists of multilayer graphene grown on a silicon carbide wafer,\u0022 First explained. \u003C\/p\u003E\u003Cp\u003EIn multilayer epitaxial graphene, each layer\u0027s symmetrical sublattice is rotated slightly with respect to the next. In prior studies, researchers found that the rotations served to decouple the electronic properties of each graphene layer. \u003C\/p\u003E\u003Cp\u003E\u0022Our findings hold the first indications of a small position-dependent interaction between the layers,\u0022 said David L. Miller, the paper\u0027s first author and a graduate student in First\u0027s laboratory. \u0022This interaction occurs only when the size of a cyclotron orbit -- which shrinks as the magnetic field is increased -- becomes smaller than the size of the observed patches.\u0022 \u003C\/p\u003E\u003Cp\u003EThe origin of the position dependent interaction is believed to be the \u0022moir\u00e9 pattern\u0022 of atomic alignments between two adjacent layers of graphene. In some regions, atoms of one layer lie atop atoms of the layer below, while in other regions, none of the atoms align with the atoms in the layer below. In still other regions, half of the atoms have neighbors in the underlayer, an instance in which the symmetry of the carbon atoms is broken and the Landau level -- discrete energy level of the electrons -- splits into two different energies. \u003C\/p\u003E\u003Cp\u003EExperimentally, the researchers examined a sample of epitaxial graphene grown at Georgia Tech in the laboratory of Professor Walt de Heer, using techniques developed by his research team over the past several years. \u003C\/p\u003E\u003Cp\u003EThey used the tip of a custom-built scanning-tunneling microscope (STM) to probe the atomic-scale electronic structure of the graphene in a technique known as scanning tunneling spectroscopy. The tip was moved across the surface of a 100-square nanometer section of graphene, and spectroscopic data was acquired every 0.4 nanometers. \u003C\/p\u003E\u003Cp\u003EThe measurements were done at 4.3 degrees Kelvin to take advantage of the fact that energy resolution is proportional to the temperature. The scanning-tunneling microscope, designed and built by Joseph Stroscio at NIST\u0027s Center for Nanoscale Science and Technology, used a superconducting magnet to provide the magnetic fields needed to study the orbits. \u003C\/p\u003E\u003Cp\u003EAccording to First, the study raises a number of questions for future research, including how the energy gaps will affect electron transport properties, how the observed effects may impact proposed bi-layer graphene coherent devices -- and whether the new phenomenon can be controlled. \u003C\/p\u003E\u003Cp\u003E\u0022This study is really a stepping stone in long path to understanding the subtleties of graphene\u0027s interesting properties,\u0022 he said. \u0022This material is different from anything we have worked with before in electronics.\u0022 \u003C\/p\u003E\u003Cp\u003EIn addition to those already mentioned, the study also included Walt de Heer, Kevin D. Kubista, Ming Ruan, and Markus Kinderman from Georgia Tech and Gregory M. Rutter from NIST. The research was supported by the National Science Foundation, the Semiconductor Research Corporation and the W.M. Keck Foundation. Additional assistance was provided by Georgia Tech\u0027s Materials Research Science and Engineering Center (MRSEC). \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003EGeorgia Institute of Technology\u003Cbr \/\u003E75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003EAtlanta, Georgia 30308 USA\u003C\/strong\u003E \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Vogel Robinson (404-385-3364)(\u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E). \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon \u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Findings May Have Implications for Device Designers"}],"field_summary":[{"value":"\u003Cp\u003EResearchers have taken one more step toward understanding the unique and often unexpected properties of graphene, a two-dimensional carbon material that has attracted interest because of its potential applications in future generations of electronic devices.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers take a new step to understanding graphene properties."}],"uid":"27303","created_gmt":"2010-08-09 00:00:00","changed_gmt":"2016-10-08 03:07:15","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-08-09T00:00:00-04:00","iso_date":"2010-08-09T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"60373":{"id":"60373","type":"image","title":"Moire alignment of graphene","body":null,"created":"1449176267","gmt_created":"2015-12-03 20:57:47","changed":"1475894523","gmt_changed":"2016-10-08 02:42:03","alt":"Moire alignment of graphene","file":{"fid":"191110","name":"tpx85581.jpg","image_path":"\/sites\/default\/files\/images\/tpx85581_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tpx85581_0.jpg","mime":"image\/jpeg","size":953599,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tpx85581_0.jpg?itok=4b2fa4es"}},"60374":{"id":"60374","type":"image","title":"Graphene Electron Motion","body":null,"created":"1449176267","gmt_created":"2015-12-03 20:57:47","changed":"1475894523","gmt_changed":"2016-10-08 02:42:03","alt":"Graphene Electron Motion","file":{"fid":"191111","name":"tdc85581.jpg","image_path":"\/sites\/default\/files\/images\/tdc85581_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tdc85581_0.jpg","mime":"image\/jpeg","size":192342,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tdc85581_0.jpg?itok=TH4hzXiY"}}},"media_ids":["60373","60374"],"related_links":[{"url":"http:\/\/www.physics.gatech.edu\/","title":"Georgia Tech School of Physics"},{"url":"http:\/\/www.mrsec.gatech.edu\/","title":"Materials Research Science and Engineering Center"},{"url":"http:\/\/www.physics.gatech.edu\/people\/faculty\/pfirst.html","title":"Phillip First"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"6884","name":"electron"},{"id":"609","name":"electronics"},{"id":"429","name":"graphene"},{"id":"10361","name":"orbits"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"55557":{"#nid":"55557","#data":{"type":"news","title":"Seeing Moire in Graphene","body":[{"value":"\u003Cp\u003EResearchers at the Georgia Institute of Technology and the National Institute of Standards and Technology (NIST) have demonstrated that atomic scale moir\u00e9 patterns, an interference pattern that appears when two or more grids are overlaid slightly askew, can be used to measure how sheets of graphene are stacked and reveal areas of strain. The ability to determine the rotational orientation of graphene sheets and map strain is useful for understanding the electronic and transport properties of multiple layers of graphene, a one-atom thick form of carbon with potentially revolutionary semiconducting properties. The research appears in the journal, Physical Review B, in volume 81, issue 12.\u003Cbr \/\u003E\u003Cbr \/\u003EIn digital photography, moir\u00e9 (pronounced mwar-ray) patterns occur because of errors in the rendering process, which causes grid patterns to look wavy or distorted. Materials scientists have been using microscopic moir\u00e9 patterns to detect stresses such as wrinkles or bulges in a variety of materials.\u003Cbr \/\u003E\u003Cbr \/\u003EResearchers created graphene on the surface of a silicon carbide substrate at the Georgia Institute of Technology by heating one side so that only carbon, in the form of multilayer sheets of graphene, was left. Using a custom-built scanning tunneling microscope at NIST, the researchers were able to peer through the topmost layers of graphene to the layers beneath. This process, which the group dubbed \u0022atomic moir\u00e9 interferometry,\u0022 enabled them to image the patterns created by the stacked graphene layers, which in turn allowed the group to model how the hexagonal lattices of the individual graphene layers were stacked in relation to one another.\u003Cbr \/\u003E\u003Cbr \/\u003EUnlike other materials that tend to stretch out when they cool, graphene bunches up like a wrinkled bed sheet. The researchers were able to map these stress fields by comparing the relative distortion of the hexagons of carbon atoms that comprise the individual graphene layers. Their technique is so sensitive that it is able to detect strains in the graphene layers causing as little as a 0.1 percent change in atom spacing.\u003Cbr \/\u003E\u003Cbr \/\u003E\u201cThere\u2019s an ideal atomic lattice spacing in graphene. Knowing the strain distribution can help us in our efforts to create graphene with good electronic properties,\u201d said Phillip N. First, professor in the School of Physics at Georgia Tech. \u201cSo far, it looks as if multi-layered graphene has excellent conduction properties and may be useful for electronic applications.\u201d\u003Cbr \/\u003E\u003Cbr \/\u003EThis collaboration between Georgia Tech and NIST is part of a series of experiments aimed at gaining a fundamental understanding of the properties of graphene. Other examples of the group\u0027s work can been seen at \u003Ca href=\u0022http:\/\/www.mrs.org\/s_mrs\/bin.asp?CID=8684\u0026amp;DID=320520\u0026amp;DOC=FILE.PDF\u0022 title=\u0022www.mrs.org\/s_mrs\/bin.asp?CID=8684\u0026amp;DID=320520\u0026amp;DOC=FILE.PDF\u0022\u003Ewww.mrs.org\/s_mrs\/bin.asp?CID=8684\u0026amp;DID=320520\u0026amp;DOC=FILE.PDF\u003C\/a\u003E and \u003Ca href=\u0022http:\/\/www.mrs.org\/s_mrs\/bin.asp?CID=26616\u0026amp;DID=320529\u0026amp;DOC=FILE.PDF\u0022 title=\u0022www.mrs.org\/s_mrs\/bin.asp?CID=26616\u0026amp;DID=320529\u0026amp;DOC=FILE.PDF\u0022\u003Ewww.mrs.org\/s_mrs\/bin.asp?CID=26616\u0026amp;DID=320529\u0026amp;DOC=FILE.PDF\u003C\/a\u003E.\u003Cbr \/\u003E\u003Cbr \/\u003ETheir article, \u0022Structural analysis of multilayer graphene via atomic moir\u00e9 interferometry\u0022 was selected as an Editor\u0027s Highlight in Physical Review B for the month of March, 2010.\u003Cbr \/\u003E\u003Cbr \/\u003EWriters: Mark Esser and David Terraso\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EResearchers at the Georgia Institute of Technology and the National Institute of Standards and Technology have demonstrated that atomic scale moir\u00e9 patterns, an interference pattern that appears when two or more grids are overlaid slightly askew, can be used to measure how sheets of graphene are stacked and reveal areas of strain. \u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers show how moire patterns can be used to meausure the strain of graphene sheets."}],"uid":"27310","created_gmt":"2010-05-05 08:55:51","changed_gmt":"2016-10-08 03:05:53","author":"David Terraso","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-05-05T00:00:00-04:00","iso_date":"2010-05-05T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"55558":{"id":"55558","type":"image","title":"Atomic Moire Pattern of Graphene","body":null,"created":"1449175533","gmt_created":"2015-12-03 20:45:33","changed":"1475894491","gmt_changed":"2016-10-08 02:41:31","alt":"Atomic Moire Pattern of Graphene","file":{"fid":"190314","name":"21977_web.jpg","image_path":"\/sites\/default\/files\/images\/21977_web_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/21977_web_0.jpg","mime":"image\/jpeg","size":73860,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/21977_web_0.jpg?itok=Vc-GC1Je"}}},"media_ids":["55558"],"groups":[{"id":"1183","name":"Home"}],"categories":[{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"429","name":"graphene"},{"id":"9244","name":"moire"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EGeorgia Tech Media Relations\u003C\/strong\u003E\u003Cbr \/\u003ELaura Diamond\u003Cbr \/\u003E\u003Ca href=\u0022mailto:laura.diamond@comm.gatech.edu\u0022\u003Elaura.diamond@comm.gatech.edu\u003C\/a\u003E\u003Cbr \/\u003E404-894-6016\u003Cbr \/\u003EJason Maderer\u003Cbr \/\u003E\u003Ca href=\u0022mailto:maderer@gatech.edu\u0022\u003Emaderer@gatech.edu\u003C\/a\u003E\u003Cbr \/\u003E404-660-2926\u003C\/p\u003E","format":"limited_html"}],"email":["david.terraso@comm.gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"54682":{"#nid":"54682","#data":{"type":"news","title":"Study Quantifies the Effects of Placing Metal Contacts on Graphene","body":[{"value":"\u003Cp\u003EUsing large-scale supercomputer calculations, researchers have analyzed how the placement of metallic contacts on graphene changes the electron transport properties of the material as a factor of junction length, width and orientation. The work is believed to be the first quantitative study of electron transport through metal-graphene junctions to examine earlier models in significant detail. \u003C\/p\u003E\u003Cp\u003EInformation on the ways in which attaching metal contacts affects electron transport in graphene will be important to scientists studying the material -- and to designers who may one day fabricate electronic devices from the carbon-lattice material. \u003C\/p\u003E\u003Cp\u003E\u0022Graphene devices will have to communicate with the external world, and that means we will have to fabricate contacts to transport current and data,\u0022 said Mei-Yin Chou, a professor and department chair in the School of Physics at the Georgia Institute of Technology. \u0022When they put metal contacts onto graphene to measure transport properties, researchers and device designers need to know that they may not be measuring the instrinsic properties of pristine graphene. Coupling between the contacts and the material must be taken into account.\u0022 \u003C\/p\u003E\u003Cp\u003EInformation on the effects of metal contacts on graphene was reported in the journal \u003Cem\u003EPhysical Review Letters\u003C\/em\u003E on February 19th. The research was supported by the U.S. Department of Energy, and involved interactions with researchers at the National Science Foundation (NSF)-supported Materials Research Science and Engineering Center (MRSEC) at Georgia Tech. \u003C\/p\u003E\u003Cp\u003EUsing large-scale, first-principles calculations done at two different NSF-supported supercomputer centers, the Georgia Tech research team -- which included postdoctoral fellows Salvador Barraza-Lopez and Mihajlo Vanevic, and assistant professor Markus Kindermann -- conducted detailed atomic-level calculations of aluminum contacts grown on graphene. \u003C\/p\u003E\u003Cp\u003EThe calculations studied two contacts up to 14 nanometers apart, with graphene suspended between them. In their calculations, the researchers allowed the aluminum to grow as it would in the real world, then studied how electron transfer was induced in the area surrounding the contacts. \u003C\/p\u003E\u003Cp\u003E\u0022People have been able to come up with phenomenological models that they use to find out what the effects are with metallic contacts,\u0022 Chou explained. \u0022Our calculations went a few steps farther because we built contacts atom-by-atom. We built atomistically-resolved contacts, and by doing that, we solved this problem at the atomic level and tried to do everything consistent with quantum mechanics.\u0022 \u003C\/p\u003E\u003Cp\u003EBecause metals typically have excess electrons, physically attaching the contacts to graphene causes a charge transfer from the metal. Charge begins to be transferred as soon as the contracts are constructed, but ultimately the two materials reach equilibrium, Chou said. \u003C\/p\u003E\u003Cp\u003EThe study showed that charge transfer at the leads and into the freestanding section of the material creates an electron-hole asymmetry in the conductance. For leads that are sufficiently long, the effect creates two conductance minima at the energies of the Dirac points for the suspended and clamped regions of the graphene, according to Barraza-Lopez. \u003C\/p\u003E\u003Cp\u003E\u0022These results could be important to the design of future graphene devices,\u0022 he said. \u0022Edge effects and the impact of nanoribbon width have been studied in significant detail, but the effects of charge transfer at the contacts may potentially be just as important.\u0022 \u003C\/p\u003E\u003Cp\u003EThe researchers modeled aluminum, but believe their results will apply to other metals such as copper and gold that do not form chemical bonds with graphene. However, other metals such as chromium and titanium do chemically alter the material, so the effects they have on electron transport may be different. \u003C\/p\u003E\u003Cp\u003EBeyond the new information provided by the calculations, the research further proposes quantitative models that can be used under certain circumstances to describe the impact of the contacts. \u003C\/p\u003E\u003Cp\u003E\u0022Earlier models had been based on physical insights, but nobody really knew how faithfully they described the material,\u0022 Kindermann said. \u0022This is the first calculation to show that these earlier models apply under certain circumstances for the systems that we studied.\u0022 \u003C\/p\u003E\u003Cp\u003EData from the study may one day help device designers engineer graphene circuits by helping them understand the effects they are seeing. \u003C\/p\u003E\u003Cp\u003E\u0022When we modify graphene, we need to understand what changes occur as a result of adding materials,\u0022 added Chou. \u0022This is really fundamental research to understand these effects and to have a numerical prediction for what is going on. We are helping to understand the basic physics of graphene.\u0022 \u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis research was supported by Department of Energy grant DE-FG02-97ER45632. Comments and conclusions in this article are those of the researchers and do not necessarily reflect the views of the Department of Energy.\u003C\/em\u003E \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003EGeorgia Institute of Technology\u003Cbr \/\u003E75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003EAtlanta, Georgia 30308 USA\u003C\/strong\u003E \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Vogel (404-385-3364)(\u003Ca href=\u0022mailto:avogel@gatech.edu\u0022\u003Eavogel@gatech.edu\u003C\/a\u003E). \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon \u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EUsing large-scale supercomputer calculations, researchers have analyzed how the placement of metallic contacts on graphene changes the electron transport properties of the material as a factor of junction length, width and orientation.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Placing contacts onto graphene changes the material\u0027s properties."}],"uid":"27303","created_gmt":"2010-02-25 01:00:00","changed_gmt":"2016-10-08 03:05:38","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-02-25T00:00:00-05:00","iso_date":"2010-02-25T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"54683":{"id":"54683","type":"image","title":"Research team and findings","body":null,"created":"1449175459","gmt_created":"2015-12-03 20:44:19","changed":"1475894481","gmt_changed":"2016-10-08 02:41:21","alt":"Research team and findings","file":{"fid":"172616","name":"tlq13442.jpg","image_path":"\/sites\/default\/files\/images\/tlq13442_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tlq13442_0.jpg","mime":"image\/jpeg","size":702218,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tlq13442_0.jpg?itok=vUuBgEHz"}},"54684":{"id":"54684","type":"image","title":"Graphic showing metal contacts","body":null,"created":"1449175459","gmt_created":"2015-12-03 20:44:19","changed":"1475894481","gmt_changed":"2016-10-08 02:41:21","alt":"Graphic showing metal contacts","file":{"fid":"172617","name":"tjy13058.jpg","image_path":"\/sites\/default\/files\/images\/tjy13058_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tjy13058_0.jpg","mime":"image\/jpeg","size":199182,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tjy13058_0.jpg?itok=-Zf8NoJS"}}},"media_ids":["54683","54684"],"related_links":[{"url":"http:\/\/www.physics.gatech.edu\/","title":"Georgia Tech School of Physics"},{"url":"http:\/\/prl.aps.org\/abstract\/PRL\/v104\/i7\/e076807","title":"Physical Review Letters paper"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"}],"keywords":[{"id":"8858","name":"contacts"},{"id":"429","name":"graphene"},{"id":"7435","name":"material"},{"id":"7415","name":"transport"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"52890":{"#nid":"52890","#data":{"type":"news","title":"One-step Process Produces Both P-type and N-type Doping in Graphene","body":[{"value":"\u003Cp\u003EA simple one-step process that produces both n-type and p-type doping of large-area graphene surfaces could facilitate use of the promising material for future electronic devices. The doping technique can also be used to increase conductivity in graphene nanoribbons used for interconnects.\u003C\/p\u003E\u003Cp\u003EBy applying a commercially-available spin-on-glass (SOG) material to graphene and then exposing it to electron-beam radiation, researchers at the Georgia Institute of Technology created both types of doping by simply varying the exposure time. Higher levels of e-beam energy produced p-type areas, while lower levels produced n-type areas. \u003C\/p\u003E\u003Cp\u003EThe technique was used to fabricate high-resolution p-n junctions. When properly passivated, the doping created by the SOG is expected to remain indefinitely in the graphene sheets studied by the researchers. \u003C\/p\u003E\u003Cp\u003E\u0022This is an enabling step toward making possible complementary metal oxide graphene transistors,\u0022 said Raghunath Murali, a senior research engineer in Georgia Tech\u0027s Nanotechnology Research Center. \u003C\/p\u003E\u003Cp\u003EA paper describing the technique appeared February 10, 2010 in the journal \u003Cem\u003EApplied Physics Letters\u003C\/em\u003E. The research was supported by the Semiconductor Research Corporation and the Defense Advanced Research Projects Agency (DARPA) through the Interconnect Focus Center. \u003C\/p\u003E\u003Cp\u003EIn the new doping process, Murali and graduate student Kevin Brenner begin by removing flakes of graphene one to four layers thick from a block of graphite. They place the material onto a surface of oxidized silicon, then fabricate a four-point contact device. \u003C\/p\u003E\u003Cp\u003ENext, they spin on films of hydrogen silsesquoxane (HSQ), then cure certain portions of the resulting thin film using electron beam radiation. The technique provides precise control over the amount of radiation and where it is applied to the graphene, with higher levels of energy corresponding to more cross-linking of the HSQ. \u003C\/p\u003E\u003Cp\u003E\u0022We gave varying doses of electron-beam radiation and then studied how it influenced the properties of carriers in the graphene lattice,\u0022 Murali said. \u0022The e-beam gave us a fine range of control that could be valuable for fabricating nanoscale devices. We can use an electron beam with a diameter of four or five nanometers that allows very precise doping patterns.\u0022 \u003C\/p\u003E\u003Cp\u003EElectronic measurements showed that a graphene p-n junction created by the new technique had large energy separations, indicating strong doping effects, he added. \u003C\/p\u003E\u003Cp\u003EResearchers elsewhere have demonstrated graphene doping using a variety of processes including soaking the material in various solutions and exposing it to a variety of gases. The Georgia Tech process is believed to be the first to provide both electron and hole doping from a single dopant material. \u003C\/p\u003E\u003Cp\u003EDoping processes used for graphene are likely to be significantly different from those established for silicon use, Murali said. In silicon, the doping step substitutes atoms of a different material for silicon atoms in the material\u2019s lattice. \u003C\/p\u003E\u003Cp\u003EIn the new single-step process for graphene, the doping is believed to introduce atoms of hydrogen and oxygen in the vicinity of the carbon lattice. The oxygen and hydrogen don\u0027t replace carbon atoms, but instead occupy locations atop the lattice structure. \u003C\/p\u003E\u003Cp\u003E\u0022Energy applied to the SOG breaks chemical bonds and releases hydrogen and oxygen which bond with the carbon lattice,\u0022 Murali said. \u0022A high e-beam energy converts the whole SOG structure to more of a network, and then you have more oxygen than hydrogen, resulting in a p-type doping.\u0022 \u003C\/p\u003E\u003Cp\u003EIn volume manufacturing, the electron beam radiation would likely be replaced by a conventional lithography process, Murali said. Varying the reflectance or transmission of the mask set would control the amount of radiation reaching the SOG, and that would determine whether n-type or p-type areas are created. \u003C\/p\u003E\u003Cp\u003E\u0022Making everything in a single step would avoid some of the expensive lithography steps,\u0022 he said. \u0022Gray-scale lithography would allow fine control of doping across the entire surface of the wafer.\u0022 \u003C\/p\u003E\u003Cp\u003EFor doping bulk areas such as interconnects that do not require patterning, the researchers simply coat the area with HSQ and expose it to a plasma source. The technique can make the nanoribbons up to 10 times more conductive than untreated graphene. \u003C\/p\u003E\u003Cp\u003EBecause HSQ is already familiar to the microelectronics industry, the one-step approach to doping could help integrate graphene into existing processes, avoiding a disruption of the massive semiconductor design and fabrication system, Murali noted. \u003C\/p\u003E\u003Cp\u003EOver the past two years, researchers in the Nanotechnology Research Center had observed changes caused by application of HSQ during electrical testing. Only recently did they take a closer look at what was happening to understand how to take advantage of the phenomenon. \u003C\/p\u003E\u003Cp\u003EFor the future, they\u0027d like to better understand how the process works and whether other polymers might provide better results. \u003C\/p\u003E\u003Cp\u003E\u0022We need to have a better understanding of how to control this process because variability is one of the issues that must be controlled to make manufacturing feasible,\u0022 Murali explained. \u0022We are trying to identify other polymers that may provide better control or stronger doping levels.\u0022 \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003EGeorgia Institute of Technology\u003Cbr \/\u003E75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003EAtlanta, Georgia 30308 USA\u003C\/strong\u003E \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Vogel (404-385-3364)(\u003Ca href=\u0022mailto:avogel@gatech.edu\u0022\u003Eavogel@gatech.edu\u003C\/a\u003E). \u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon \u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"A simple one-step process that produces both n-type and p-type doping of large-area graphene surfaces could facilitate use of the promising material for future electronic devices.","format":"limited_html"}],"field_summary_sentence":[{"value":"A simple doping technique could facilitate graphene devices"}],"uid":"27303","created_gmt":"2010-02-11 01:00:00","changed_gmt":"2016-10-08 03:05:33","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2010-02-11T00:00:00-05:00","iso_date":"2010-02-11T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"52891":{"id":"52891","type":"image","title":"Electrical measurements of graphene","body":null,"created":"1449175459","gmt_created":"2015-12-03 20:44:19","changed":"1475894476","gmt_changed":"2016-10-08 02:41:16","alt":"Electrical measurements of graphene","file":{"fid":"146095","name":"toj27664.jpg","image_path":"\/sites\/default\/files\/images\/toj27664_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/toj27664_0.jpg","mime":"image\/jpeg","size":1326151,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/toj27664_0.jpg?itok=e5Df_xSv"}},"52892":{"id":"52892","type":"image","title":"Graduate student Kevin Brenner","body":null,"created":"1449175459","gmt_created":"2015-12-03 20:44:19","changed":"1475894476","gmt_changed":"2016-10-08 02:41:16","alt":"Graduate student Kevin Brenner","file":{"fid":"146096","name":"the27664.jpg","image_path":"\/sites\/default\/files\/images\/the27664_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/the27664_0.jpg","mime":"image\/jpeg","size":1386708,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/the27664_0.jpg?itok=TvoYkyqH"}},"52893":{"id":"52893","type":"image","title":"Graduate student Kevin Brenner","body":null,"created":"1449175459","gmt_created":"2015-12-03 20:44:19","changed":"1475894476","gmt_changed":"2016-10-08 02:41:16","alt":"Graduate student Kevin Brenner","file":{"fid":"146097","name":"tpa27664.jpg","image_path":"\/sites\/default\/files\/images\/tpa27664_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tpa27664_0.jpg","mime":"image\/jpeg","size":735708,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tpa27664_0.jpg?itok=if3W9je0"}}},"media_ids":["52891","52892","52893"],"related_links":[{"url":"http:\/\/www.nrc.gatech.edu\/","title":"Nanotechnology Research Center"},{"url":"http:\/\/www.mirc.gatech.edu\/raghu\/","title":"Raghunath Murali"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"8458","name":"doping"},{"id":"609","name":"electronics"},{"id":"429","name":"graphene"},{"id":"7435","name":"material"},{"id":"4261","name":"transistor"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"46254":{"#nid":"46254","#data":{"type":"news","title":"Graphene Shows High Current Capacity \u0026 Thermal Conductivity","body":[{"value":"\u003Cp\u003ERecent research into the properties of graphene nanoribbons provides two new reasons for using the material as interconnects in future computer chips.  In widths as narrow as 16 nanometers, graphene has a current carrying capacity approximately a thousand times greater than copper -- while providing improved thermal conductivity.\u003C\/p\u003E\n\u003Cp\u003EThe current-carrying and heat-transfer measurements were reported by a team of researchers from the Georgia Institute of Technology.  The same team had previously reported measurements of resistivity in graphene that suggest the material\u0027s conductance would outperform that of copper in future generations of nanometer-scale interconnects.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Graphene nanoribbons exhibit an impressive breakdown current density that is related to the resistivity,\u0022 said Raghunath Murali, a senior research engineer in Georgia Tech\u0027s Nanotechnology Research Center.  \u0022Our measurements show that these graphene nanoribbons have a current carrying capacity at least two orders of magnitude higher than copper at these size scales.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EMeasurements of thermal conductivity and breakdown current density in narrow graphene nanoribbons were reported June 19 in the journal \u003Cem\u003EApplied Physics Letters\u003C\/em\u003E.  The research was supported by the Semiconductor Research Corporation\/DARPA through the Interconnect Focus Center and by the Nanoelectronics Research Initiative through the Institute for Nanoelectronics Discovery and Exploration (INDEX). \n\u003C\/p\u003E\n\u003Cp\u003EThe unique properties of graphene -- which is composed of thin layers of graphite -- make it attractive for a wide range of potential electronic devices.  Murali and his colleagues have been studying graphene as a potential replacement for copper in on-chip interconnects, the tiny wires that are used to connect transistors and other devices on integrated circuits.  Use of graphene for these interconnects, they believe, would help extend the long run of performance improvements in integrated circuit technology.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Our measurements show that graphene nanoribbons have a current carrying capacity of more than 10^8 amps per square centimeter, while a handful of them exceed 10^9 amps per square centimeter,\u0022 Murali said. \u0022This makes them very robust in resisting electromigration and should greatly improve chip reliability.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EElectromigration is a phenomenon that causes transport of material, especially at high current density.  In on-chip interconnects, this eventually leads to a break in the wire, which results in chip failure.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We are learning a lot of new things about this material, which will lead researchers to consider other potential applications,\u0022 said Murali.  \u0022In addition to the high current carrying capacity, graphene nanoribbons also have excellent thermal conductivity.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EBecause heat generation is a significant cause of device failure, the researchers also measured the ability of the graphene nanostructures to conduct heat away from devices.  They found that graphene nanoribbons have a thermal conductivity of more than 1,000 watts per meter Kelvin for structures less than 20 nanometers wide.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022This high thermal conductivity could allow graphene interconnects to also serve as heat spreaders in future generations of integrated circuits,\u0022 said Murali.  \n\u003C\/p\u003E\n\u003Cp\u003ETo study the properties of graphene interconnects, Murali and collaborators Yinxiao Yang, Kevin Brenner, Thomas Beck and James Meindl began with flakes of multi-layered graphene removed from a graphite block and placed onto an oxidized silicon substrate.  They used electron beam lithography to construct four electrode contacts, then used lithography to fabricate devices consisting of parallel nanoribbons of widths ranging between 16 and 52 nanometers and lengths of between 0.2 and 1 micron.\n\u003C\/p\u003E\n\u003Cp\u003EThe breakdown current density of the nanoribbons was then studied by slowly applying an increasing amount of current to the electrodes on either side of the parallel nanoribbons.  A drop in current flow indicated the breakdown of one or more of the nanoribbons.\n\u003C\/p\u003E\n\u003Cp\u003EIn their study of 21 test devices, the researchers found that the breakdown current density of graphene nanoribbons has a reciprocal relationship to the resistivity. \n\u003C\/p\u003E\n\u003Cp\u003EBecause graphene can be patterned using conventional chip-making processes, manufacturers could make the transition from copper to graphene without a drastic change in chip fabrication.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Graphene has very good electrical properties,\u0022 Murali said.  \u0022The data we have developed so far looks very promising for using this material as the basis for future on-chip interconnects.\u0022\t\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 100\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\u003C\/strong\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986); E-mail: (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Vogel (404-385-3364); E-mail: (\u003Ca href=\u0022mailto:avogel@gatech.edu\u0022\u003Eavogel@gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\n\u003C\/p\u003E\n\u003Cp\u003E\u003C\/p\u003E\n\u003Cp\u003E\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Study Examined Graphene Nanoribbons as Narrow as 16 Nanometers"}],"field_summary":[{"value":"Recent research into the properties of graphene nanoribbons provides two new reasons for using the material as interconnects in future computer chips.","format":"limited_html"}],"field_summary_sentence":[{"value":"Research gives new reasons for using graphene in computer chips"}],"uid":"27303","created_gmt":"2009-07-29 00:00:00","changed_gmt":"2016-10-08 03:03:14","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2009-07-29T00:00:00-04:00","iso_date":"2009-07-29T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"46255":{"id":"46255","type":"image","title":"Graphene nanoribbons","body":null,"created":"1449174375","gmt_created":"2015-12-03 20:26:15","changed":"1475894414","gmt_changed":"2016-10-08 02:40:14","alt":"Graphene nanoribbons","file":{"fid":"101048","name":"tco80273.jpg","image_path":"\/sites\/default\/files\/images\/tco80273_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tco80273_0.jpg","mime":"image\/jpeg","size":174089,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tco80273_0.jpg?itok=a-DN97Uv"}}},"media_ids":["46255"],"related_links":[{"url":"http:\/\/www.youtube.com\/watch?v=kd6zzwhfEqw","title":"Graphene Nanoscale Heat Pipes for Chip Cooling (YouTube Video)"},{"url":"http:\/\/www.nrc.gatech.edu\/","title":"Nanotechnology Research Center"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"2505","name":"conductivity"},{"id":"2123","name":"current"},{"id":"429","name":"graphene"},{"id":"432","name":"nanoribbon"},{"id":"7112","name":"thermal"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"46304":{"#nid":"46304","#data":{"type":"news","title":"Graphene May Have Advantages Over Copper for Future IC Interconnects","body":[{"value":"\u003Cp\u003EThe unique properties of thin layers of graphite -- known as graphene -- make the material attractive for a wide range of potential electronic devices.  Researchers have now experimentally demonstrated the potential for another graphene application: replacing copper for interconnects in future generations of integrated circuits.\u003C\/p\u003E\n\u003Cp\u003EIn a paper published in the June 2009 issue of the IEEE journal \u003Cem\u003EElectron Device Letters\u003C\/em\u003E, researchers at the Georgia Institute of Technology report detailed analysis of resistivity in graphene nanoribbon interconnects as narrow as 18 nanometers.\n\u003C\/p\u003E\n\u003Cp\u003EThe results suggest that graphene could out-perform copper for use as on-chip interconnects -- tiny wires that are used to connect transistors and other devices on integrated circuits.  Use of graphene for these interconnects could help extend the long run of performance improvements for silicon-based integrated circuit technology.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022As you make copper interconnects narrower and narrower, the resistivity increases as the true nanoscale properties of the material become apparent,\u0022 said Raghunath Murali, a research engineer in Georgia Tech\u0027s Microelectronics Research Center and the School of Electrical and Computer Engineering.  \u0022Our experimental demonstration of graphene nanowire interconnects on the scale of 20 nanometers shows that their performance is comparable to even the most optimistic projections for copper interconnects at that scale.  Under real-world conditions, our graphene interconnects probably already out-perform copper at this size scale.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EBeyond resistivity improvement, graphene interconnects would offer higher electron mobility, better thermal conductivity, higher mechanical strength and reduced capacitance coupling between adjacent wires.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Resistivity is normally independent of the dimension -- a property inherent to the material,\u0022 Murali noted.  \u0022But as you get into the nanometer-scale domain, the grain sizes of the copper become important and conductance is affected by scattering at the grain boundaries and at the side walls.  These add up to increased resistivity, which nearly doubles as the interconnect sizes shrink to 30 nanometers.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe research was supported by the Interconnect Focus Center, which is one of the Semiconductor Research Corporation\/DARPA Focus Centers, and the Nanoelectronics Research Initiative through the INDEX Center.\n\u003C\/p\u003E\n\u003Cp\u003EMurali and collaborators Kevin Brenner, Yinxiao Yang, Thomas Beck and James Meindl studied the electrical properties of graphene layers that had been taken from a block of pure graphite.  They believe the attractive properties will ultimately also be measured in graphene fabricated using other techniques, such as growth on silicon carbide, which now produces graphene of lower quality but has the potential for achieving higher quality.  \n\u003C\/p\u003E\n\u003Cp\u003EBecause graphene can be patterned using conventional microelectronics processes, the transition from copper could be made without integrating a new manufacturing technique into circuit fabrication.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We are optimistic about being able to use graphene in manufactured systems because researchers can already grow layers of it in the lab,\u0022 Murali noted.  \u0022There will be challenges in integrating graphene with silicon, but those will be overcome. Except for using a different material, everything we would need to produce graphene interconnects is already well known and established.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EExperimentally, the researchers began with flakes of multi-layered graphene removed from a graphite block and placed onto an oxidized silicon substrate.  They used electron beam lithography to construct four electrode contacts on the graphene, then used lithography to fabricate devices consisting of parallel nanoribbons of widths ranging between 18 and 52 nanometers.  The three-dimensional resistivity of the nanoribbons on 18 different devices was then measured using standard analytical techniques at room temperature.\n\u003C\/p\u003E\n\u003Cp\u003EThe best of the graphene nanoribbons showed conductivity equal to that predicted for copper interconnects of the same size.  Because the comparisons were between non-optimized graphene and optimistic estimates for copper, they suggest that performance of the new material will ultimately surpass that of the traditional interconnect material, Murali said.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Even graphene samples of moderate quality show excellent properties,\u0022 he explained.  \u0022We are not using very high levels of optimization or especially clean processes.  With our straightforward processing, we are getting graphene interconnects that are essentially comparable to copper.  If we do this more optimally, the performance should surpass copper.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThough one of graphene\u0027s key properties is reported to be ballistic transport -- meaning electrons can flow through it without resistance -- the material\u0027s actual conductance is limited by factors that include scattering from impurities, line-edge roughness and from substrate phonons -- vibrations in the substrate lattice.  \n\u003C\/p\u003E\n\u003Cp\u003EUse of graphene interconnects could help facilitate continuing increases in integrated circuit performance once features sizes drop to approximately 20 nanometers, which could happen in the next five years, Murali said.  At that scale, the increased resistance of copper interconnects could offset performance increases, meaning that without other improvements, higher density wouldn\u0027t produce faster integrated circuits.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022This is not a roadblock to achieving scaling from one generation to the next, but it is a roadblock to achieving increased performance,\u0022 he said.  \u0022Dimensional scaling could continue, but because we would be giving up so much in terms of resistivity, we wouldn\u0027t get a performance advantage from that.  That\u0027s the problem we hope to solve by switching to a different materials system for interconnects.\u0022\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 100\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\u003C\/strong\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986); E-mail: (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Vogel (404-385-3364); E-mail: (\u003Ca href=\u0022mailto:avogel@gatech.edu\u0022\u003Eavogel@gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\n\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"New Material May Replace Traditional Metal at Nanoscale Widths"}],"field_summary":[{"value":"Georgia Tech researchers have experimentally demonstrated the potential for another application of graphene: replacing copper for interconnects in future generations of integrated circuits.","format":"limited_html"}],"field_summary_sentence":[{"value":"Graphene could replace copper for nanoscale IC interconnects"}],"uid":"27303","created_gmt":"2009-06-04 00:00:00","changed_gmt":"2016-10-08 03:03:14","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2009-06-04T00:00:00-04:00","iso_date":"2009-06-04T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"46305":{"id":"46305","type":"image","title":"Graphene interconnects","body":null,"created":"1449174375","gmt_created":"2015-12-03 20:26:15","changed":"1475894414","gmt_changed":"2016-10-08 02:40:14","alt":"Graphene interconnects","file":{"fid":"101083","name":"tyf17432.jpg","image_path":"\/sites\/default\/files\/images\/tyf17432_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tyf17432_0.jpg","mime":"image\/jpeg","size":890854,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tyf17432_0.jpg?itok=P0xy4pJx"}},"46306":{"id":"46306","type":"image","title":"Testing graphene","body":null,"created":"1449174375","gmt_created":"2015-12-03 20:26:15","changed":"1475894414","gmt_changed":"2016-10-08 02:40:14","alt":"Testing graphene","file":{"fid":"101084","name":"tai17432.jpg","image_path":"\/sites\/default\/files\/images\/tai17432_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tai17432_0.jpg","mime":"image\/jpeg","size":1304054,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tai17432_0.jpg?itok=FCpn2p9a"}},"46307":{"id":"46307","type":"image","title":"Microscope image","body":null,"created":"1449174375","gmt_created":"2015-12-03 20:26:15","changed":"1475894416","gmt_changed":"2016-10-08 02:40:16","alt":"Microscope image","file":{"fid":"101085","name":"tni17432.jpg","image_path":"\/sites\/default\/files\/images\/tni17432_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tni17432_0.jpg","mime":"image\/jpeg","size":158173,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tni17432_0.jpg?itok=TrysqtjE"}}},"media_ids":["46305","46306","46307"],"related_links":[{"url":"http:\/\/www.mirc.gatech.edu\/","title":"Microelectronics Research Center"},{"url":"http:\/\/www.mirc.gatech.edu\/raghu\/","title":"Raghunath Murali"},{"url":"http:\/\/ieeexplore.ieee.org\/xpl\/freeabs_all.jsp?arnumber=4968006\u0026count=43\u0026index=12\u0026isnumber=4968003","title":"Paper in Electron Device Letters"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"}],"keywords":[{"id":"429","name":"graphene"},{"id":"433","name":"IC"},{"id":"430","name":"interconnects"},{"id":"432","name":"nanoribbon"},{"id":"431","name":"nanoscale"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"46320":{"#nid":"46320","#data":{"type":"news","title":"Graphene Yields Secrets to its Extraordinary Properties","body":[{"value":"\u003Cp\u003EApplying innovative measurement techniques, researchers from the Georgia Institute of Technology and the National Institute of Standards and Technology (NIST) have directly measured the unusual energy spectrum of graphene, a technologically promising, two-dimensional form of carbon that has tantalized and puzzled scientists since its discovery in 2004.\u003C\/p\u003E\n\u003Cp\u003EPublished in the May 15, 2009 issue of the journal \u003Cem\u003EScience\u003C\/em\u003E, the work adds new detail to help explain the unusual physical phenomena and properties associated with graphene, a single layer of carbon atoms arrayed in a repeating, honeycomb-like arrangement.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Our experiments directly measured the energy spectrum of graphene with unprecedented precision and show that the unique multilayer epitaxial graphene grown in the Georgia Tech laboratory of Walt de Heer behaves remarkably like independent graphene sheets,\u0022 said Philip N. First, an associate professor in the Georgia Tech School of Physics and one of the paper\u0027s co-authors.  \u0022This effective single-layer behavior is due to small rotations between the graphene sheets that dramatically reduce the interlayer atomic interactions.  Because the measurements showed only very small surface potential fluctuations and long times between scattering events, it could be that this multilayer material is one of the best places to study many properties of \u0027single-layer\u0027 graphene.\u0022 \n\u003C\/p\u003E\n\u003Cp\u003EThe research was funded by the National Science Foundation, the Semiconductor Research Corporation through the Nanoelectronics Research Initiative INDEX Program, and by the W.M. Keck Foundation.\n\u003C\/p\u003E\n\u003Cp\u003EGraphene\u0027s exotic behaviors present intriguing prospects for future technologies, including high-speed, graphene-based electronics that might replace today\u0027s silicon-based integrated circuits and other devices. Even at room temperature, electrons in graphene are more than 100 times more mobile than in silicon.\n\u003C\/p\u003E\n\u003Cp\u003EGraphene apparently owes this enhanced mobility to the curious fact that its electrons and other carriers of electric charges behave as though they do not have mass. In conventional materials, the speed of electrons is related to their energy, but not in graphene. Although they do not approach the speed of light, the research team found that unbound electrons in graphene behave much like photons, massless particles that also move at a speed independent of their energy.\n\u003C\/p\u003E\n\u003Cp\u003EThis weird massless behavior is associated with other strangeness, the researchers found. When ordinary conductors are put in a strong magnetic field, charge carriers such as electrons begin moving in circular orbits that are constrained to discrete, equally spaced energy levels. In graphene these levels are known to be unevenly spaced because of the \u0022massless\u0022 electrons.\n\u003C\/p\u003E\n\u003Cp\u003EThe Georgia Tech\/NIST team tracked these massless electrons in action, using a specialized NIST instrument to zoom in on the graphene layer at a billion times magnification, tracking the electronic states while at the same time applying high magnetic fields. The custom-built, ultra-low-temperature and ultra-high-vacuum scanning tunneling microscope allowed them to sweep an adjustable magnetic field across graphene samples prepared at Georgia Tech, observing and mapping the peculiar non-uniform spacing among discrete energy levels that form when the material is exposed to magnetic fields.\n\u003C\/p\u003E\n\u003Cp\u003EThe team developed a high-resolution map of the distribution of energy levels in graphene. In contrast to metals and other conducting materials, where the distance from one energy peak to the next is uniformly equal, this spacing is uneven in graphene.\n\u003C\/p\u003E\n\u003Cp\u003EThe researchers also probed and spatially mapped graphene\u0027s hallmark \u0022zero energy state,\u0022 a curious phenomenon where the material has no electrical carriers until a magnetic field is applied.\n\u003C\/p\u003E\n\u003Cp\u003EThe measurements also indicated that layers of graphene grown and then heated on a substrate of silicon carbide behave as individual, isolated, two-dimensional sheets. On the basis of the results, the researchers suggest that graphene layers are uncoupled from adjacent layers because they stack in different rotational orientations. This finding may point the way to manufacturing methods for making large, uniform batches of graphene for a new carbon-based electronics.\n\u003C\/p\u003E\n\u003Cp\u003EThe research team included David L. Miller, Kevin D. Kubista, Ming Ruan, Walt A. de Heer and Philip N. First of Georgia Tech\u0027s School of Physics, and Gregory M. Rutter and Joseph A. Stroscio of the Center for Nanoscale Science and Technology at NIST.\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 100\u003Cbr \/\u003E\nAtlanta, Georgia 30308 USA\u003C\/strong\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts:\u003C\/strong\u003E\u003Cbr \/\u003E\n* NIST: Mark Bello (301-975-3776); (\u003Ca href=\u0022mailto:mark.bello@nist.gov\u0022\u003Emark.bello@nist.gov\u003C\/a\u003E).\u003Cbr \/\u003E\n* Georgia Tech: John Toon (404-894-6986); (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Vogel (404-385-3364); (\u003Ca href=\u0022mailto:avogel@gatech.edu\u0022\u003Eavogel@gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter:\u003C\/strong\u003E Mark Bello\n\u003C\/p\u003E\n\u003Cp\u003E\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Research Advances Potential Applications in Electronics"}],"field_summary":[{"value":"Applying innovative measurement techniques, researchers from the Georgia Institute of Technology and the National Institute of Standards and Technology (NIST) have directly measured the unusual energy spectrum of graphene, a technologically promising, two-dimensional form of carbon.","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers confirm theoretical predictions regarding graphene"}],"uid":"27303","created_gmt":"2009-05-16 00:00:00","changed_gmt":"2016-10-08 03:03:14","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2009-05-16T00:00:00-04:00","iso_date":"2009-05-16T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"46321":{"id":"46321","type":"image","title":"Measuring graphene","body":null,"created":"1449174401","gmt_created":"2015-12-03 20:26:41","changed":"1475894416","gmt_changed":"2016-10-08 02:40:16","alt":"Measuring graphene","file":{"fid":"101095","name":"thl83186.jpg","image_path":"\/sites\/default\/files\/images\/thl83186_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/thl83186_0.jpg","mime":"image\/jpeg","size":178668,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/thl83186_0.jpg?itok=P112k8lv"}},"46322":{"id":"46322","type":"image","title":"Test equipment","body":null,"created":"1449174401","gmt_created":"2015-12-03 20:26:41","changed":"1475894416","gmt_changed":"2016-10-08 02:40:16","alt":"Test equipment","file":{"fid":"101096","name":"tiy83186.jpg","image_path":"\/sites\/default\/files\/images\/tiy83186_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/tiy83186_0.jpg","mime":"image\/jpeg","size":863774,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/tiy83186_0.jpg?itok=K6CfxPH_"}}},"media_ids":["46321","46322"],"related_links":[{"url":"http:\/\/www.physics.gatech.edu\/","title":"Georgia Tech School of Physics"},{"url":"http:\/\/www.mrsec.gatech.edu\/","title":"Materials Research Science and Engineering Center"},{"url":"http:\/\/cnst.nist.gov\/","title":"NIST Center for Nanoscale Science and Technology"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"153","name":"Computer Science\/Information Technology and Security"},{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"}],"keywords":[{"id":"610","name":"carbon"},{"id":"611","name":"conduction"},{"id":"609","name":"electronics"},{"id":"608","name":"electrons"},{"id":"429","name":"graphene"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"70873":{"#nid":"70873","#data":{"type":"news","title":"Georgia Tech Awarded New Center to Study Potential Silicon Successor","body":[{"value":"\u003Cp\u003EThe National Science Foundation (NSF) has awarded funding to the Georgia Institute of Technology to create a new Materials Research Science and Engineering Center (MRSEC)- The Georgia Tech Laboratory for New Electronic Materials.\n\u003C\/p\u003E\n\u003Cp\u003EThe Laboratory will focus its efforts on the development of new materials to serve as the successors to silicon in the semiconductor industry. Specifically, the development of graphene - which holds tremendous promise as an electronic material - will be the initial core of research and development at the Center.\n\u003C\/p\u003E\n\u003Cp\u003ENSF funding will be $8.1 million for six years of research and development. The MRSEC office suite will be housed in the Georgia Tech\u0027s new Marcus Nanotechnology Research Center Building.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022This is an exciting time for graphene research,\u0022 said Dennis Hess, director of the Georgia Tech MRSEC. \u0022Our studies may allow the manufacture of microelectronic devices and integrated circuits based on graphene. The Georgia Tech team, in conjunction with external partners, has already pioneered the use of epitaxial graphene to achieve such goals. Georgia Tech Physics Professors Walt de Heer, Phil First and Ed Conrad are worldwide leaders in the growth and characterization of epitaxial graphene. We look forward to additional innovative discoveries from our Center over the next few years.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe Laboratory will be a cross-disciplinary effort utilizing the talent and resources of Georgia Tech and four additional institutions: University of California Berkeley, University of California Riverside, Alabama A \u0026amp; M and the University of Michigan. Georgia Tech will initially have 13 faculty members involved in the Laboratory\u0027s efforts, with five additional members representing the partner schools. Collaborations are already in place with several companies and national laboratories within the U.S. and abroad.\n\u003C\/p\u003E\n\u003Cp\u003EGraphene, a sheet of carbon only one-atom thick, holds the potential to become the core material for computer processors in electronics, which continue to become smaller in size. Silicon, comparatively, has fundamental limitations that inhibit operation in ever-shrinking devices used in microelectronics, optics and sensors.\n\u003C\/p\u003E\n\u003Cp\u003EGeorgia Tech will develop the fundamental science and technology to maximize graphene\u0027s potential as a component in future electronics technologies. In addition, the Center will provide the core curriculum, train a diverse workforce and develop the future academic and industrial leaders needed for this new direction in the semiconductor industry. \n\u003C\/p\u003E\n\u003Cp\u003EAn industrial advisory board is being assembled for the Center, which will include representatives from leading electronics companies.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022This new MRSEC complements Georgia Tech\u0027s multiple programs and investments in nanotechnology extremely well,\u0022 said Professor Mark Allen, senior vice provost for Research and Innovation.  \u0022Much of the work will take place in our Nanotechnology Research Center, a new facility dedicated to research into both inorganic and organic nanoscience and nanotechnology.  We look forward to enabling the next generation of graphene electronics through the efforts of the researchers in this new MRSEC.\u0022\n\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"The National Science Foundation (NSF) has awarded funding to the Georgia Institute of Technology to create a new Materials Research Science and Engineering Center (MRSEC)- The Georgia Tech Laboratory for New Electronic Materials.","format":"limited_html"}],"field_summary_sentence":[{"value":"NSF funding to help facilitate development of graphene"}],"uid":"27281","created_gmt":"2008-10-13 00:00:00","changed_gmt":"2016-10-08 03:01:15","author":"Lisa Grovenstein","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2008-10-13T00:00:00-04:00","iso_date":"2008-10-13T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"70874":{"id":"70874","type":"image","title":"Tech Tower","body":null,"created":"1449177328","gmt_created":"2015-12-03 21:15:28","changed":"1475894623","gmt_changed":"2016-10-08 02:43:43"}},"media_ids":["70874"],"groups":[{"id":"1214","name":"News Room"}],"categories":[{"id":"153","name":"Computer Science\/Information Technology and Security"},{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"}],"keywords":[{"id":"516","name":"engineering"},{"id":"429","name":"graphene"},{"id":"107","name":"Nanotechnology"},{"id":"363","name":"NSF"},{"id":"167609","name":"semiconductor"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cstrong\u003EDon Fernandez\u003C\/strong\u003E\u003Cbr \/\u003EMarketing and Communications\u003Cbr \/\u003E\u003Ca href=\u0022mailto:don.fernandez@comm.gatech.edu\u0022\u003EContact Don Fernandez\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6016\u003C\/strong\u003E","format":"limited_html"}],"email":["don.fernandez@comm.gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}