Direct correlations of bulk charged and neutral defect densities of states in a-Si:H films with characteristics of Schottky barrier solar cell structures

We report a systematic study on the a-Si:H thin film materials with different densities of charged defects which are incorporated in Schottky barrier solar cell structures. The densities of charged and neutral defects were obtained from photoconductivity and sub-bandgap absorption measurements and using the sub-bandgap absorption model (SAM). Current-voltage characteristics at different temperatures and internal quantum efficiencies were measured on the corresponding SnO/a-Si:H(n⁺)/a-Si:H(i)/Ni Schottky barrier structures and the results were modeled using AMPS. It was found that for structures thicker than ~1.5 μm. Schottky barrier characteristics can be fitted using the same densities and parameters for the charged and neutral defects as obtained from SAM without having to invoke effects from the interface layer