Bio

Yu-Hsin Liu is now a Ph.D. candidate in Materials Science and Engineering program in UCSD. She received her Master degree in Materials Science and Engineering from National Tsing Hua University (NTHU)at Taiwan in 2009. She had worked as research assistant in NTHU for one year and became a Ph.D student of UCSD in 2010. In the department of Electrical and Computer Engineering, she has been working on optoelectronics and semiconductor devices and has an extensive background in fabrication process development, device characterizations, simulations and modelings. She also has experiences in micro- fabrication and microfluidics devices development from internship working with Illumina and Nano3 Facility (Nanoscience, Nanoengineering, and Nanomedicine). Currently her research interests are in cycling excitation process, a new signal amplification process for Si photodetectors.

Silicon p-n junction photodetectors

Silicon p-n junction photodetectors

Yu-Hsin’s research focuses on silicon p-n junction structures applied to photodetectors, which are compatible with COMS fabrication process and without involving defects. By using space confinement and heavy doping in nanoscaled p-n junction structures to relax the k-selection rule for Si materials, efficient 1310 nm light detection has been demonstrated. The nanowire and waveguide devices show efficient sub-bandgap bias-dependent photoresponse without involving any defects or surface states.
On the other hand, she also demonstrated high gain in heavily doped and partially compensated p-n junction devices at visible wavelength. Compared to avalanche photodiodes based on impact ionization, her photodetectors using the Cycling Excitation Process (CEP) for signal amplification, experience smaller excess noise and can be operated at very low bias (<4V). CEP also possesses an intrinsic, phonon-mediated regulation process to keep the device stable without the quenching components required in today’s Geiger-mode avalanche detectors.