First-principles calculations of indirect Auger recombination in nitride semiconductors

TL;DR

This paper develops a first-principles computational method to analyze both direct and indirect Auger recombination in nitride semiconductors, revealing phonon-assisted processes as the main cause of non-radiative losses affecting device efficiency.

Contribution

It introduces a general first-principles formalism for calculating Auger recombination rates, specifically applying it to nitride materials and highlighting the significance of phonon-assisted processes.

Findings

Direct Auger recombination is weak in nitrides.

Phonon-assisted and alloy disorder processes dominate Auger recombination.

Charged-defect scattering is less significant for realistic defect densities.

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 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.