EXCESS CARRIER DISPERSION IN CONVENTIONALLY DISPERSIVE AMORPHOUS-SEMICONDUCTORS AND THE MOBILITY-LIFETIME ANOMALY IN A-SI-H

The paper describes a numerical method for the simulation of "time-of-flight" transport measurements in amorphous semiconductors. The method is applied in a study of quasi-equilibrium transport such as observed in a-Si:H at T > 250K. It is demonstrated that the mu-tau-product measured by charge-collection methods can be simply an artefact associated with high modes of diffusion loss to the sample electrodes. The results may explain the systematic discrepancy in values of mu-tau measured by different methods.