Surface studies by means of 45 degrees reflectometry

The presence of surface structures and very thin films on materials is in general difficult to detect by optical techniques except in situations where the surface structure is anisotropic or the growth of the film can be followed in situ. In this paper we demonstrate that the relation R(s)(2)(45 degrees)=R(p)(45 degrees), which is valid for all clean isotropic materials irrespective the value of the dielectric constants, can be used as a basis for an experimental technique, allowing submonolayer detectivity without following a process in situ. This is demonstrated by measuring the tarnish films on silver films in air and by measuring the anisotropic surface response of the Si(110) surface.