Observation of photoinduced changes in the bulk density of gap states in hydrogenated amorphous silicon

Abstract
We have observed a reversible photoinduced modification of the bulk density of gap states in a-Si:H associated with the Staebler–Wronski effect. A detailed numerical analysis of diode admittance and deep level transient spectroscopy measurements shows that the changes in these properties after illumination can be explained by a lowering of the bulk Fermi level and an increase in the density of states below midgap.