Speaker：Prof.Jung Han,Yale University.

Time: 10:00a.m.Monday,March 14

Place: D111 SINANO

Abstract:

So far the impact and promise of GaN devices are focused mainly on optoelectronic and microelectronic devices. The blue LEDs and their inventors have been recognized with Nobel prizes, and GaN power transistors are positioned to play a key role in compact energy efficient power electronics.

The ability to grow single-crystalline semiconductor material on amorphous surfaces present a unique challenge using traditional growth techniques. We have recently demonstrated single crystal GaN growth by employing the general phenomenon in film deposition of evolutionary selection. In the concept that has been proposed and demonstrated, evolutionary selection (ES) was employed in first a vertical, then in a lateral direction, allowing a final single crystal of GaN to be formed. This was implemented by deposition of an (0001) oriented AlN layer on a SiO2/Si(100) substrate. A SiO2 confined mask structure is then formed, and subsequent lateral selective area growth of GaN by MOCVD using AlN as a seed, produced site-selected placement of GaN and eliminated the in-plane misalignment.

In the 2nd half of the presentation we will talk about new development in GaN photonics. The exploration of GaN in photonic devices and structures, which seeks to manipulate optical density of states and propagation properties through linear and non-linear optical index engineering, has received much less attention. In this talk we will summarize our effort in making GaN resonators in one, two, and three dimensions. We will review the performance and challenges associated with different fabrication pathways. With the use of a novel electrochemical process, we are able to selectively porosify or electro-polish GaN. The electrochemical process enables unprecedented tuning in the index of refraction, making it possible to create optical confined structures and laser diodes.

The research is supported by US Department of Energy, National Science Foundation, and DARPA.

Bio:

Professor Jung Han is the William A Norton Professor of Technology Inovation at Yale University, and has been the Chair of the Department of Electrical Engineering since 2010. His current research activities includes the visible InGaN light emitting structures for energy-efficient solid state lighting, nano-scale synthesis of AlGaInN heterostructures, and novel optoelectronics and miroelectronics. The awards he received include R&D 100 (2004), MRS Ribbon Award (2005), and EMC best paper award (2014). He has published more than 230 papers in peer-reviewed journals with a total citation of more than 8,600 citations and an H-index of 46. He holds 8 US patents and is a co-founder of a startup company Saphlux based on his inventions. He is a member of Connecticut Academy of Science and Engineering (CASE) and a Fellow of Institute of Physics (IoP) and Institute of Electrical and Electronic Engineers (IEEE). 

Welcome to attend!