NONEQUILIBRIUM EFFECTS IN PHOTOEMISSION FROM METAL-SEMICONDUCTOR INTERFACES

It has recently been shown that the determination of surface band bending in clean and adsorbate-covered semiconductor surfaces may be seriously affected by non-equilibrium processes induced by the photoemission soft X-ray light source. These effects are often large enough to completely mask the actual equilibrium band bending. We present a complication of experimental data and model calculations which clearly establish the wide-ranging nature of such effects, and their influence on previous studies of metal overlayers on the (110) surfaces of III-V semiconductors, which have been used as model systems in the past. It is demonstrated that metallization of the overlayer does not seem to play a role in establishing the Schottky barrier, as we previously believed. More recent applications of surface photovoltage, for example in the study of laterally resolved recombination centers at surfaces, are also discussed.