OSE Seminar by Prof. Emmanouil (Manos) Kioupakis on Understanding and mitigating the efficiency challenges of nitride light emitters

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Posted: February 11, 2020

Date: Thursday, February 13, 2020

Time:  11:30 AM to 12:30 PM

Location:  CHTM, Room 101

Map to CHTM:

http://www.chtm.unm.edu/about/map-directions.html

ADA Accommodations are available.

Speaker:

Emmanouil (Manos) Kioupakis 

Associate Professor and Karl F. and Patricia J. Betz Family Faculty Scholar

Department of Materials Science and Engineering, University of Michigan

Abstract:

In this talk, I will discuss results from atomistic calculations aimed to understand and mitigate the factors that limit the efficiency of group-III nitride visible and UV optoelectronic devices. I will discuss our findings about the magnitude and microscopic origin of radiative recombination and non-radiative Auger annihilation in InGaN and AlGaN alloys, with a focus on the effects of electron-phonon coupling and alloy disorder on the recombination rates. I will also present our findings on overcoming the challenges of current technology with novel materials. I will present our results on the stability and radiative recombination of room-temperature-stable excitons in atomically thin GaN and InN. I will also discuss how Boron incorporation in InGaN and AlGaN yields quaternary BInGaN and BAlGaN alloys that are lattice-matched to GaN and AlN, respectively with band gaps that span the visible and UV range, correspondingly. I will further present our findings on how stacking disorder and electron-phonon coupling affect the luminescence properties of boron nitride. This work was performed in collaboration with Andrew McAllister, Chris Van de Walle, Dylan Bayerl, Debdeep Jena, Grace Xing, Woncheol Lee, Nocona Sanders, Logan Williams, Kevin Greenman, Kelsey Mengle, and Zetian Mi. Computational resources were provided by the DOE NERSC facility (DE-AC02-05CH11231). This work was supported by the NSF through grant nos. 1254314, 1607796, and 1534221.

References:
[1] Applied Physics Letters 109, 241102 (2016).
[2] Nano Letters 17, 7345 (2017).
[3] Applied Physics Letters 111, 211107 (2017).
[4] Optics Express 26, 23031 (2018).
[5] APL Materials 7, 021106 (2019).

 

Biography:

Emmanouil (Manos) Kioupakis is an Associate Professor of Materials Science and Engineering and of Applied Physics, and the Karl F. and Patricia J. Betz Family Faculty Scholar at the University of Michigan. His work focuses on the theoretical characterization and discovery of novel inorganic semiconductors. He has received the CAREER award by the NSF, the Jon R. and Beverly S. Holt Award for Excellence in Teaching, and the 1938E Award by the College of Engineering of the University of Michigan.