Light induced changes in the density of states of a-Si:H

Thermally stimulated conductivity (TSC) and photoconductivity were measured before and after light irradiation in hydrogenated amorphous silicon (a-Si:H) films prepared by glow discharge technique. It was observed that even medium-level of exposure to light decreased both the TSC and photoconductivity by nearly an order of magnitude over a temperature range between ∼ 100 and 300 K. From these measurements the density of gap states (DOS) between the dark Fermi level and conduction band mobility edge were calculated for the samples before and after light irradiation and the DOS was found to increase with light exposure at 105 KPublisher's Versio