Strain Effects on Auger-Meitner Recombination in Silicon

Auger-Meitner 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). Due to silicon's conduction band valley degeneracy, strain engineering offers a possible route to tune this intrinsic recombination mechanism. In this work, we use first principles methods to quantify the effects of biaxial strain on both the direct and phonon-assisted Auger-Meitner recombination. Our analysis reveals a competition between the initial distribution of electrons across all six conduction band valleys in the unstrained case with increased occupation in the lower energy valleys upon the application of strain. This competition leads to an increase in the potency of the intravalley recombination processes compared to the perpendicular valley (f-type) configuration. Furthermore, we find that as in the unstrained material, the phonon-assisted process remains dominant under strained conditions. This work offers insight into a possible engineering route to adjust the intrinsic non-radiative recombination rate, which affects the overall efficiency for devices such as silicon solar cells.