Seminar by Dr. Der-Hsien LIEN on 2D Semiconductor Optoelectronics: From Material Properties to Device Innovations

Date: 19 June 2018 (Tuesday)

Time: 9:30 am

Venue: G5-215, Yeung Kin Man Academic Building

Two-dimensional (2D) materials have emerged as a promising material system for electronic and optoelectronic applications. In this talk, I will present our recent advancements in improving material quality as well as developing light-emitting devices of the monolayer chalcogenides. We developed a defect passivation technique that enables the monolayer MoS2 to achieve near-unity quantum yield. The work presents the first demonstration of an optoelectronically perfect monolayer. Moving forward to the device development, forming electron and hole selected contacts is a necessary step for a light-emitting device but is challenging for 2D monolayers. We circumvent this challenge via a new device design that allows for high-level injection of electrons and holes without the requirement of ohmic contacts. We are able to show the first millimeter-scale light emission in 2D materials and fabricate transparent digital display using this new device design. Additionally, I will discuss the challenges of the materials system and possible solutions towards high efficient monolayer light-emitting devices.

Biography

Der-Hsien (Danny) Lien is a Postdoctoral Fellow at University of California, Berkeley. He received his Ph.D. degree in Electrical Engineering from National Taiwan University in 2015. His current research is focusing on the physics of 2D materials and their optoelectronic applications. He has performed research in other fields including printable electronics, ultrasonic thermal imaging, and devices for energy harvesting. His first-authored papers have appeared in the leading journals and conference, including Science, Nature Communications, and Symposia on VLSI Technology, etc. He has authored or co-authored over 50 SCI papers and hold 4 U.S. patents. He is the recipient of several prestigious awards including IEEE EDS PhD Student Fellowship in 2015.

Enquiry:

Department of Materials Science and Engineering

Email: mse@cityu.edu.hk

Tel: 3442 2985