Atomistic simulation of light-induced changes in hydrogenated amorphous silicon

We employ ab initio molecular dynamics to simulate the response of hydrogenated amorphous silicon (a-Si:H) to light exposure (the Staebler-Wronski effect). We obtain improved microscopic understanding of photovoltaic operation, compute the motion of H atoms, and modes of light-induced degradation of photovoltaics. We clarify existing models of light-induced change in a-Si:H and show that the 'hydrogen collision model' of Branz (1998 Solid State Commun. 105/106 387) is correct in many essentials.