Intensity and temperature dependence of the steady-state light-induced defect density ina-Si:H

Abstract

The steady-state defect density in hydrogenated amorphous silicon (a-Si:H) under illumination was investigated for a wide range of illumination intensities and temperatures. The steady-state defect density under illumination is consistent with a chemical equilibrium model for defect generation, similar to the one used to describe defect generation in a-Si:H by doping and by thermal quenching. According to the model, defect generation is enhanced under illumination due to the reduction of the effective defect formation energy when the bands are populated by photogenerated carriers. Defect generation under illumination is a self-limiting process, and the defect density reaches a saturation value at long illumination time despite the existence of an extended distribution of defect formation sites.