Auger Recombination in GaAs from First Principles

Auger recombination is a significant loss mechanism in many optoelectronic devices. We use first-principles methods based on density functional theory to study the relative importance of direct and indirect phonon-assisted Auger recombination in GaAs and related alloys. Energy and momentum, of the recombining electron-hole pair can be transferred, to an Auger eleetron, (eeh process) or an Auger hole (hhe process). For eeh processes, the direct process is negligibly small compared to the phonon-assisted indirect process in GaAs, while in hhe processes the direct and phonon-assisted processes contribute almost equally The hole processes are about 5 times stronger than the electron processes. In alloys with lower band gaps, the eeh processes become stronger, and below a band gap of 0.8 eV they are as relevant as the hole processes. Our results highlight the importance of indirect processes, even at low band gaps.