Surface differential reflectivity for studying surface state optical transitions - a review

In this paper we present an overview of the method of surface differential reflectivity (SDR) for the study of semiconductor surfaces. We will describe the principles of the technique and the experimental apparatus together with some theoretical considerations concerning the connection of SDR with the microscopic properties of the surface. In particular, the analysis of SDR is done in the frame of a macroscopic three layers model in which the media involved (vacuum, surface and substrate) are assumed to have definite anisotropic dielectric functions. A few experimental results, indicative of the potential of the technique, will be shown.