THEORY OF SURFACE PHOTOVOLTAGE IN A SEMICONDUCTOR WITH A SCHOTTKY CONTACT

An analytical theory of surface photovoltage is developed for a semico nductor with a Schottky contact. The theory is able to predict, for li ght with small to large absorption coefficients, the photon flux requi red to yield a specified photovoltage, taking into account the three c urrent components that describe the internal behaviour of the semicond uctor, namely, the surface current, the space-charge recombination cur rent and the bulk diffusion current. Detailed modelling of these curre nt components is done with the help of exact numerical solutions of th e drift-diffusion transport equations. The validity of the theory is c onfirmed by comparison with exact numerical solutions over a wide rang e of doping concentrations and minority-carrier lifetimes.