Speaker:Shi Zhisheng, School of Electrical and Computer Engineering, University of Oklahoma
Date: March 18, 2013
Time:1:30 p.m.
Location:Lecture Hall of the School of Information Science and Engineering
Sponsor:School of Information Science and Engineering
Abstract:In this talk, the development of IV-VI uncooled mid-IR semiconductor detectors and photonic crystal (PC) lasers is presented. For nearly a century, oxygen has been widely accepted as the key element that triggers photo-response in polycrystalline PbSe photoconductive detectors. Our photoluminescence and responsivity studies on PbSe samples, however, suggest that oxygen only serves as an effective sensitization improver and it is iodine rather than oxygen that plays the key role in triggering the photo-response. As a result, record high detectivity was achieved at room temperature. We also demonstrate a mid-infrared surface-emitting photonic crystal laser on silicon substrate operating at room temperature. The active region consisting of PbSe/PbSrSe multiple quantum wells was grown by MBE on Si(111) substrate patterned with a PC array. The PC array forms a transverse magnetic polarized photonic bandgap. Under pulsed optical pumping, room temperature multimode lasing emissions were observed at wavelength 3.5 μm. Such PC lasers could be used as compact integrated laser gas sensors for environmental and medical applications.
Zhisheng Shireceived his Ph.D. degree in optoelectronic materials in 1995 from Physics Department in Albert-Ludwig-University in Germany. He was a Research Scholar Fellow of German Aerospace Administration from 1992 to 1995. From 1995 to 1997, he was a research staff at Swiss Federal Institute of Technology (ETH). He has been a faculty member in the School of Electrical and Computer Engineering at the University of Oklahoma since 1997. He was honored as Gerald Tuma Presidential Professor in 2007. He is the founder and president of Nanolight Inc, a spin-off company developing mid/long-IR detector, mid-IR lasers and 3rd generation solar cells. He and his students have published about 60 peer-reviewed articles in the field of semiconductor thin film growth, nano/micro-semiconductor fabrication, laser and detector.
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