杨志忠 教授
台湾大学光电所
地点：唐仲英楼B501
时间：2019-04-11 16:00
We first review our accomplishments in using surface plasmon (SP) coupling for enhancing the emission efficiency of a GaN-based light-emitting diode (LED), including the records of ~90 % in internal quantum efficiency and 722 MHz in modulation bandwidth. Then, we focus on the experimental and numerical study results of enhancing the color conversion efficiency of a blue LED into red light through SP coupling based on fabricated surface Ag nanoparticles (NPs) and chemically synthesized Au/Ag NPs. The SP resonance induced on surface Ag NPs can simultaneously couple with the quantum wells of the blue LED and the bottom layer of the overlaid quantum dots (QDs) for enhancing QW emission efficiency, and the absorption and emission efficiencies of QDs. The chemically synthesized Au/Ag NPs can mix and link with QDs for overlaying at the LED top. Their SP resonance can couple with QDs nearby for enhancing their absorption and emission efficiencies. Therefore, the overall color conversion efficiency can be significantly increased. For this purpose, the SP resonance spectra of the fabricated metal NPs need to cover the blue and red spectral ranges. In this study, we also implement theoretical and numerical studies for understanding the color conversion enhancement mechanisms.
Professor Yang received his BS and Ph.D. degrees, both in electrical engineering, from National Taiwan University and University of Illinois at Urbana-Champaign, in 1976 and 1984, respectively. After nine year service as a faculty member at the Pennsylvania State University, he returned to Taiwan in 1993 and became a faculty member in the Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, in which he is currently a distinguished professor. Professor Yang has published about 300 SCI journal papers and made more than 700 presentations at prestigious international conferences, including over 130 invited talks. His research areas include MBE and MOCVD growths of wide-band-gap semiconductor nanostructures, LED fabrication, plasmonics, and bio-photonics. Professor Yang is a fellow of Optical Society of America and a fellow of SPIE. He is also a recipient of the MOST outstanding research award.