Computer-assisted study of carrier thermalization by hopping in disordered semiconductors

Abstract

Techniques for the analysis of hopping transport in disordered semiconductors are outlined and applied to the thermalization of charge carriers within a particular distribution of localized states (N(E)). The transient current is superficially similar to that for the case of trap-limited band transport. However, techniques developed assuming the dominance of this process in the calculation of N(E) yield totally erroneous results. Also, the derived values of the attempt-to-escape frequency, ν_ph, and capture cross section, σ, of the trapping centers are unrealistically small. This may well explain the anomalous results obtained in various experimental studies. The use of data obtained at different temperatures to calculate ν_ph and σ is therefore proposed as a valuable new procedure for differentiating between hopping and trap-limited band transport.