Theory of surface photovoltage in a semiconductor with a Schottky contact

Abstract

An analytical theory of surface photovoltage is developed for a semiconductor with a Schottky contact. The theory is able to predict, for light with small to large absorption coefficients, the photon flux required to yield a specified photovoltage, taking into account the three current components that describe the internal behaviour of the semiconductor, namely, the surface current, the space-charge recombination current and the bulk diffusion current. Detailed modelling of these current components is done with the help of exact numerical solutions of the drift-diffusion transport equations. The validity of the theory is confirmed by comparison with exact numerical solutions over a wide range of doping concentrations and minority-carrier lifetimes.