Il Ki Han received the Ph.D degree in physics from Yonsei University, Seoul, Korea, in 1996. Since 1989, he has been with Korea Institute of Science and Technology (KIST), where he is currently a principal research scientist at Center for Opto-electronic Conversion System. From 1998 to 1999 and 2005 to 2006, he was with the University of Maryland at College Park, as a research associate and visiting scholar, respectively. His current research interests include quantum dot and well based optical devices such as high-power laser diodes, LEDs, superluminescent diodes, quantum cascade lasers, III-V multijunction solar cells and quantum dot based high efficiency solar cells. He has published over 100 scientific journal papers on semiconductor devices and technologies.