Advances in the elucidation of hydrogen-related defects in hydrogenated amorphous silicon

The role of interstitial (mobile) hydrogen in the creation of structural defects in doped hydrogenated amorphous silicon (a-Si:H) is elucidated by first reviewing recent calculations of their electronic states. Two new processes involving hydrogen interstitials are proposed. In the first, a neutral hydrogen atom reacts with a dopant atom to produce a charged dopant-interstitial pair. In the other process, suggested by Muon Spin Resonance (MuSR) experiments, neutral hydrogen diffuses to charged silicon dangling bonds, where charge transfer occurs between the two species. These two chemical processes are then put together to show how dopants may produce charged defects in a-Si:H.