As a member of ECE Professor John Cressler's Silicon-Heterostructure Devices and Circuits research team, Jiahui's research focuses on the detailed understanding of the fundamental scaling issues of SiGe heterojunction bipolar transistors (HBTs), and to date centers on two areas: 1) using operating temperature a tuning knob for both enhancing performance to better define the ultimate speed limits of such devices, as well as uncovering new device physics phenomena in these operating temperature extremes; and 2) defining a viable scaling path towards TeraHertz (THz = 1,000 GHz) bandwidth in SiGe HBTs. THz electronics is a newly emergent research thrust in the electronics community, with numerous envisioned applications in the high mm-wave and THz imaging and communications areas.