Are there Charged Dangling Bonds in Device Quality Amorphous Silicon?

Abstract

We discuss the possible existence of a considerable density of charged dangling bond defects in device-quality hydrogenated amorphous silicon, which for example has been postulated by recent thermal equilibrium models for the density-of-states distribution. Based on a quantitative analysis of spin resonance and light-induced spin resonance data at different temperatures as well as on subgap absorption measurements, we conclude that intrinsic a-Si:H only has a small density of charged defects caused by unintentional impurity doping. The same conclusion also holds for light-soaked a-Si:H and for samples which are dehydrogenated by annealing at high temperatures.