The Diffusion Behaviour of Charge Carriers in the Dember Effect on Dye/Single-Crystal AgBr System

Abstract

The diffusion mode of photo-induced charge carriers in the single crystal AgBr Studied in this paper changes with the decay time of the response. For a sufficiently long time the product of the number of free holes and their diffusion length becomes larger than that of the number of free electrons and their diffusion length due to electron-traps existing in AgBr single crystal. The dominant carriers in six dyes studied in the experiments are photoelectrons. The negative Dember signals on dye/single-crystal AgBr systems were caused by the diffusion of the positive holes which were generated from single crystal AgBr phase. The diffusion direction of the free carriers in the systems varies with monochromatic light wavelengths due to the occurrence of the sign reversal.