Spatial distribution of dangling bonds in undoped hydrogenated amorphous silicon observed by solid-state voltcoulometry

We use solid-state voltcoulometry (SSVC) to investigate hydrogenated amorphous silicon (a-Si:H). In this technique, a charge transient in response to a potential step, ΔU, applied to undoped a-Si:H based metal/insulator/semiconductor (MIS) structure is measured as a function of the bias voltage, Ub. By sweeping Ub, i.e., by shifting the crossovers of the Fermi level with a dangling bond (DB) defect band throughout the a-Si:H film, the SSVC measurements provide information about the spatial distribution of all DB components in a sample under test. Also, the SSVC technique is able to detect the photo-induced changes in the spatial distribution of all DB components.