Investigation of light-induced defect depth profile in hydrogenated amorphous silicon films

We have investigated the light-induced defects (LIDs) depth profiles in hydrogenated amorphous silicon films using electron spin resonance in combination with the layer-by-layer etching technique. This method enables us to study the LIDs depth profiles without the influence of film thickness on defect creation kinetics. We observed the uniform LIDs creation in the films by uniformly absorbed light exposure, indicating the absence of a sensitive layer against defects creation. The LIDs depth profile agrees with the simulated photocarrier bimolecular recombination rate profile rather than the profile of the total recombination rate or that through defects. We demonstrate that the asymmetry of the band tails modifies the defect creation kinetics predicted from the bimolecular recombination model.