Colloquium 09-10-22

Speaker:

Yong-Hang Zhang

Arizona State University, Department of Electrical Engineering and Director: Center for Nanophotonics

Title:

6.1 Å II-VI and III-V semiconductors and their application to multi-junction solar cells

Host:

Stanley Pau

Abstract:

Semiconductor optoelectronic materials and devices have experienced very rapid development for more than half a century. However, there still remains a lack of closely lattice-matched materials and substrates suitable for the grand integration of various kinds of semiconductor optoelectronic devices on a single chip. We have recently proposed a new material platform: the 6.1 Å II-VI (MgZnCd)(SeTe) and III-V (AlGaIn)(PAsSb) semiconductor materials lattice-matched to GaSb and InAs substrates.  These materials have direct bandgaps covering a very broad energy spectrum from far IR (~0 eV) to UV (~3.4eV). This feature is not achievable by any other known lattice-matched semiconductors on any commercially available substrates. Such a unique material platform enables invention of new light emitting devices, multijunction solar cells, multicolor photodetectors and FPAs, and facilitates monolithic integration without misfit dislocations to ensure the best materials quality.  This talk will focus on the application to ultra-high efficiency solar cells. Our detailed modeling and preliminary experimental results have shown great potential of this material platform for solar cells as well as other optoelectronic devices and their monolithic integration

Bio:

Professor Zhang received his BS and MS in China and PhD in Physics from the Max Planck Institute for Solid States and the University of Stuttgart in 1991. He then worked as an Assistant Research Engineer at UCSB before he joined Hughes Research Labs in 1993. In 1996, he was appointed Associate Professor in the Department of Electrical Engineering at ASU and was then promoted to full professor in 2000. He is the founding director of the Center for Nanophotonics at ASU. His areas of research interest include MBE growth, optical properties of semiconductor heterostructures, optoelectronic devices, and their applications. More information about his group can be found the webpage: http://asumbe.eas.asu.edu/