Black Holes Induced Slow Light in Indirect Band Gap Semiconductors for Extreme Optoelectronic Device Performance
M. Saif Islam
Department of Electrical and Computer Engineering
University of California, Davis
12 PM, Thursday, March 2nd, 2017
1003 Kemper Hall
Abstract: Micro and nanoscale holes on the surfaces of indirect band gap semiconductors such as Si and GaP enable perpendicular light bending and trapping to enhance photon absorption by more than an order of magnitude. The “bending” of vertically oriented light at nearly 90 degrees can be visualized as radial waves generated by a pebble drop in a still pool of water. Such bending and photon trapping result in an increased optical absorption path enabling very high light absorption coefficients. This observation, for the first time, led to the design of silicon photodetectors with broadband high efficiency and record ultrafast response required by modern data centers for more than 10s of billion bits of data per second (Gb/s) communication speed. A photovoltaic device designed with 2µm thin silicon shows more than 70% improvement in the energy conversion efficiency. We will discuss new opportunities for engineering indirect band gap materials to show properties like direct band gap materials.
Biography: M. Saif Islam received his B.Sc. Degree in Physics from Middle East Technical University (1994, Turkey), M.S. degree in Physics from Bilkent University (1996, Turkey) and Ph.D. degree in Electrical Engineering from UCLA in 2001. He worked for SDL Inc./JDS Uniphase Corporation, Gazillion Bits, Inc. and Hewlett-Packard Laboratories as a Staff Scientist, a Senior Scientist and a Postdoctoral Research Fellow. He joined University of California – Davis in 2004, where he is a Professor of the Electrical and Computer Engineering Department now.
Prof. Islam’s current research objectives include the development of massively parallel and mass-manufacturable synthesis and integration processes for 1D micro/nanostructures for potential applications in electronics, photonics, energy conversion and sensing. He has authored/co-authored more than 180 scientific papers, organized 20 conferences/symposiums as a chair/co-chair; and holds 38 patents as an inventor/co-inventor. He received NSF Faculty Early Career Award (2006), Outstanding Junior Faculty Award (2006) and Mid-Career Research Faculty Award (2012), IEEE Professor of the Year (2005 and 2009) and Academic Senate Distinguished Teaching Award in 2010. He is an elected fellow of the National Academy of Inventors (2014).