About My Research

Interests: Optoelectronics and high speed electronic devices and device physics, including lasers, transistors, modulators, detectors, and bio-electronic interfaces.

III-V MOSFETs

• As a postdoc at U.C. Santa Barbara, I am currently leading the growth and fabrication teams which are making some of the first (and we hope soon the best) III-V MOSFETs. This work is a delightful collaboration among multiple groups and different universities, ranging from atomic theory to circuits and from California to Massachusetts. At UCSB (as at Stanford), the boundaries between departments are fuzzy, leading to some of the most exciting research collaborations, with different viewpoints available to tackle any problem, and new and interesting challenges every day.
• Scaled InGaAs MOSFETs: III-V materials have much higher electron velocities than Si but lack a passivating, insulating oxide. However, the CMOS industry already is using exotic gate dielectrics such as HfO2, so the time has come to make nanometer scale (20-50nm) III-V MOSFETs and extend Moore's Law yet again.

Silicon Photonics and Heteroepitaxy

• Silicon photonics: Growth of defect-free Ge on Si using novel gas precursors. This enables both GaAs-based optoelectronics and III-V CMOS on silicon. The Ge was nearly strain-neutral at typical device temperatures, providing improved reliability for high power devices. Developed a full device process flow for GeSn photodetectors and modulators in the mid-IR.

High Speed Optoelectronics

• 1540nm VCSELs: The first electrically-pumped, dilute nitride VCSELs in the telecommunication band near 1550 nm, for inexpensive, high speed fiber communications. (See reprints at left.) My PhD thesis (5.9 MB) and orals abstract are available too.