Growth and Epitaxy of Materials for Multilayer X-ray Optics

Abstract

New material pairs are needed to provide useful mirrors at wavelengths where currently none exist, and to improve on performance at wavelengths where there are existing mirrors. In this paper we discuss our studies of selected new materials. Our studies take a surface analysis approach toward characterizing reactions at interfaces, the sharpness of interfaces, and the effect of the thin film growth mode on roughness. The studies were carried out in molecular beam epitaxy systems for two reasons: to study epitaxial growth of promising materials as a step toward single-crystal multilayer mirrors, and to exploit the powerful analytical tools available for surface analysis in a UHV environment. Growth of Be-, and B-based materials pairs have been studied with a wide variety of techniques including Auger, XPS, RHEED, LEED, and STM with the goal of determining interface structure, overlayer morphology, and crystal structure.