Light-induced changes in hydrogenated amorphous silicon: anomalous recombination behaviour at low temperatures

Abstract

The open circuit voltage decay (OCVD) method has been used to characterise a-Si:H, p-i-n photovoltaic cells over a range of temperatures from 228 K to 291 K. We have found that the form of the OCVD voltage-time curves is sensitive to light soaking: the curves at different temperatures for as-deposited samples are nested inside each other with similar overall decay times, whereas, for the light soaked samples, as the temperature decreased the decay time increases markedly successive curves overlap. Our preliminary results indicate that the phenomena observed may be related to the overshoot in the transient photocurrent observed by other researchers under similar condition