Gaining an Atomistic Understanding of Auger Recombination in Crystalline Silicon

Auger recombination is an intrinsic, non-radiative recombination mechanism involving three carriers – either two electrons and a hole (eeh) or two holes and an electron (hhe). Despite silicon's overwhelming importance as a semiconductor, the microscopic mechanisms of Auger recombination in silicon remain poorly understood. In this work, we use first principles methods to probe both direct Auger, where momentum is strictly conserved by the recombining electrons and holes, as well as indirect (phonon-assisted) Auger, which is enabled by the additional momentum provided via electron-phonon coupling. We demonstrate that phonon-assisted Auger is the dominant mechanism for both the eeh and hhe processes. Our results are in excellent agreement with experimental measurements. Furthermore, our analysis reveals that it may be possible to tune the Auger recombination rate in silicon via strain engineering. Ultimately, our work paves the way for a clearer understanding of this important recombination mechanism in silicon, and points to engineering solutions that may improve the efficiency of silicon devices such as solar cells.