THE INFLUENCE OF SPECULAR INTERFACE REFLECTION ON GRAZING-INCIDENCE X-RAY-DIFFRACTION AND DIFFUSE-SCATTERING FROM SUPERLATTICES

Superlattices (SL) with a large difference in the refractive index between the alternating layers give rise to specular reflection from the intrinsic interfaces of the SL which proves very efficient for small incident or exit angles near the critical angle of total external reflection. This influences the intensity of grazing incidence X-ray diffraction (GID) and non-specular X-ray scattering (NSXR). Additional peaks were found besides the common features. They are explained by waves scattered in transmission geometries and measured above the sample surface due to subsequent specular interface reflection. The experimental findings are interpreted by Umweganregung in terms of the distorted wave Born approximation (DWBA).