Following directly the effect of the various deep states on the phototransport properties of a-Si:H

Undoped samples of a-Si:H were studied by the surface photovoltage spectroscopy (SPS) and the photocarrier grating (PCG) techniques, before and after light soaking. It was found that prior to degradation two distinct deep localized levels can be detected, and that the main effect of light soaking is to create states which lie between them. However, there are more subtle features to light soaking so that in materials which are very similar otherwise, different concentration ratios of neutral to charged dangling bond are created during degradation.