Accurate determination of the two carriers steady-state mobility-lifetime products in hydrogenated amorphous silicon

Abstract

The photocarrier grating (PCG) technique is used for the first time in the high electric field regime. The results are shown to confirm previously unproven theoretical predictions for this regime. It is demonstrated that, by application of the PCG technique in the high-field regime, accurate values for the ratio of the two carriers mobility-lifetime products can be deduced. This is in contrast with the fact that their sum cannot be derived accurately from the measurement of photoconductivity because one cannot determine accurately the carrier generation rate. Combining the ratio, determined by the high field PCG, with the low-field data yields accurate values for the mobility-lifetime products of both carriers.