Photocurrent reversal and time-of-flight in amorphous silicon-hydrogen films

Abstract

The response to a reversal of the applied electric field during and after a photocurrent transient in a-Si : H type alloys has been studied for a variety of device structures, such as a back-to-back Schottky, a simple Schottky, and a p i -n typediode. The samples had thicknesses ranging from 0.4 to 6.5 pm and the measure-ments were performed between -40°C and +20°C. The study shows the effect ofcurrent reversal in all the samples. However, the current reversal can be masked by various disturbances, some of which are discussed in detail. The results are consistent with the carrier mobilities derived from time-of-flight experiments.