Density of states from transient photoconductivity in polycrystalline CdSe films

Abstract

To interpret power law decays observed for excess electrons and trapped electrons in CdSe thin films, two approaches have been compared: first, a method based on the Orenstein and Kastner model for exponential distribution of localised states, and second, an approach based on numerical solution of multiple trapping rate equations. It is shown that the second approach removes some inconsistencies inherent in the Orenstein and Kastner model. To provide a complete quantitative characterisation of the CdSe sample, saturation-bimolecular recombination effects must be included in the multiple trapping model.