Showing 1–2 of 2 results for author: Steiauf, D

First-principles calculations of indirect Auger recombination in nitride semiconductors

Authors: Emmanouil Kioupakis, Daniel Steiauf, Patrick Rinke, Kris T. Delaney, Chris G. Van de Walle

Abstract: Auger recombination is an important non-radiative carrier recombination mechanism in many classes of optoelectronic devices. The microscopic Auger processes can be either direct or indirect, mediated by an additional scattering mechanism such as the electron-phonon interaction. Phonon-assisted Auger recombination is particularly strong in nitride materials and affects the efficiency of nitride opt… ▽ More Auger recombination is an important non-radiative carrier recombination mechanism in many classes of optoelectronic devices. The microscopic Auger processes can be either direct or indirect, mediated by an additional scattering mechanism such as the electron-phonon interaction. Phonon-assisted Auger recombination is particularly strong in nitride materials and affects the efficiency of nitride optoelectronic devices at high powers. Here we present a first-principles computational formalism for the study of direct and indirect Auger recombination in direct-band-gap semiconductors and apply it to the case of nitride materials. We show that direct Auger recombination is weak in the nitrides and cannot account for experimental measurements. On the other hand, carrier scattering by phonons and alloy disorder enables indirect Auger processes that can explain the observed loss in devices. We analyze the dominant phonon contributions to the Auger recom- bination rate and the influence of temperature and strain on the values of the Auger coefficients. Auger processes assisted by charged-defect scattering are much weaker than the phonon-assisted ones for realistic defect densities and not important for the device performance. The computational formalism is general and can be applied to the calculation of the Auger coefficient in other classes of optoelectronic materials. △ Less

Submitted 10 August, 2015; v1 submitted 23 December, 2014; originally announced December 2014.

Journal ref: Phys. Rev. B 92, 035207 (2015)

First-Principles Calculations of Luminescence Spectrum Line Shapes for Defects in Semiconductors: The Example of GaN and ZnO

Authors: Audrius Alkauskas, John L. Lyons, Daniel Steiauf, Chris G. Van de Walle

Abstract: We present a theoretical study of broadening of defect luminescence bands due to vibronic coupling. Numerical proof is provided for the commonly used assumption that a multi-dimensional vibrational problem can be mapped onto an effective one-dimensional configuration coordinate diagram. Our approach is implemented based on density functional theory with a hybrid functional, resulting in luminescen… ▽ More We present a theoretical study of broadening of defect luminescence bands due to vibronic coupling. Numerical proof is provided for the commonly used assumption that a multi-dimensional vibrational problem can be mapped onto an effective one-dimensional configuration coordinate diagram. Our approach is implemented based on density functional theory with a hybrid functional, resulting in luminescence lineshapes for important defects in GaN and ZnO that show unprecedented agreement with experiment. We find clear trends concerning effective parameters that characterize luminescence bands of donor- and acceptor-type defects, thus facilitating their identification. △ Less

Submitted 12 March, 2013; originally announced March 2013.

Journal ref: Phys. Rev. Lett. 109, 267401 (2012)