Transient Photoconductivity in Multilayer Photoreceptors of As_xSe_100-x/Se

Abstract

The carrier transport properties in multilayer photoreceptors of As_xSe_100-x/Se have been investigated by the time-of-flight method. The time dependence of the photocurrent is characterized by an initial decrease, a subsequent increase and a final fall in current. Such currents are observed for the electron transport in the case x = 3-15, and for the hole transport in the case x=15-40 atomic %. The time when the current shows the maximum value after a flash-light exposure is found to be dominantly affected by the spread of carrier packet passing through the first layer (As_xSe_100-x), unlike a previously reported Se₉₆Te₄/Se photoreceptor. The time dependence observed for the electron transport (x = 3-15) is roughly explained by assuming the gaussian distribution of carriers drifting in the first layer. On the other hand, the photocurrent due to the hole transport (x = 15-40) may be interpreted in terms of the nongaussian distribution (dispersive transport model). Furthermore, multilayer photoreceptors may serve for determining the transit time of carriers in a photoconductive layer exhibiting only a featureless decay if it alone is examined for this aim.