A theoretical analysis of the relaxation of an open-circuit photopotential in a highly biased n-type semiconductor electrode: Part I. No interfacial electron or hole transfer

Abstract

The effect of pulsed photogeneration of electron-hole pairs in a semiconductor electrode is examined for the special case where there is no interfacial electron or hole transfer. The open-circuit photopotential can decay by three mechanisms: (1) Recombination of electrons and holes, either band-to-band or modified by recombination centers; (2) surface recombination effected by a high concentration of mid-gap states located at the surface; (3) diffusion of holes back into the semiconductor bulk which is shown to be relatively slow. Mathematical expressions are derived which describe the decay of the photopotential as a function of time and of the pertinent semiconductor parameters.