Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session H29: First-principles Modeling of Excited-State Phenomena in Materials VI: Solids and Layered Materials
2:30 PM–5:30 PM,
Tuesday, March 6, 2018
LACC Room: 406A
Sponsoring Units: DCOMP DMP DCP DCMP
Chair: Amanda J. Neukirch, Los Alamos National Laboratory
Abstract: H29.00006 : Ab Initio Radiative Lifetimes in Gallium Nitride*
3:54 PM–4:06 PM
(Physics, University of Rome)
Wurtzite GaN is the primary semiconductor for efficient solid state lighting. Light emission in materials is regulated by the dynamics of excited carriers, which is not completely understood in GaN. In particular, due to the ultrafast (fs – ps) timescales at play and to the presence of defects and interfaces in devices, the intrinsic radiative recombination rate is challenging to measure in GaN. Here, we present ab initio calculations of the radiative lifetime as a function of temperature in bulk GaN. We compute the exciton energies and wavefunctions using a combination density functional theory and the GW-Bethe Salpeter equation method. An equation for the ab initio temperature dependent radiative lifetime in a bulk crystal is derived using Fermi’s Golden rule and applied to GaN. Combined with previous first principles calculations of excited carrier relaxation in GaN , we can obtain from first principles key device parameters such as the hot carrier cooling time and the carrier diffusion lengths, with important technological implications.
 V.A. Jhalani, J.J. Zhou, and M. Bernardi. "Ultrafast Hot Carrier Dynamics in GaN and its Impact on the Efficiency Droop." Nano Letters 17, 5012 (2017).
*V.J. thanks the Resnick Sustainability Institute at Caltech for fellowship support.
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