Distribution of fast and slow states by photoelectric measurements on real InSb and Si surfaces

Abstract

At T = 79 K, X rays change the surface properties of n and p type InSb single cryslals as well as the properties of Si-MOS structures. In order to study the influence of surface parameters the distributions of fast and slow surface states were measured at various stages of irradiation. The distribution of fast states on real InSb surfaces has been investigated by techniques similiar to those employed in measurements of current voltage characteristics. By using a combination of integral ac field effect with differential ac field effect the continuous spectrum of fast states was studied not only within the depletion region but also under strong accumulation and inversion. Analysis of photodischarging spectroscopy gives information on the energetic location of slow surface states on real Si surfaces.