Transport and the electronic structure of hydrogenated amorphous silicon

Abstract

The puzzles of the magnitude of the free-electron mobility and the sign of the effective correlation energy of the dangling-bond defect in hydrogenated amorphous silicon are examined. It is suggested that the existence of a negative effective correlation energy in the less-strained regions of the material can resolve the apparently contradictory results for the magnitude of the band mobility. The internal fields arising from the presence of positively and negatively charged dangling bonds can be neutralized under high-level double-injection conditions, effectively increasing the mobility by more than an order of magnitude. We present experimental results that are consistent with the hypothesis.