Structural Properties of Semiconductor Nanostructures from X-Ray Scattering

Abstract

The optical and electrical properties of self-assembled semiconductor nanostructures are strongly affected by their chemical composition and strain state. These depend sensitively on the growth conditions. X-ray diffraction techniques are used in order to investigate series of SiGe/Si(001) island samples grown by molecular beam epitaxy at various temperatures. The chemical composition distribution and the in-plane strain of uncapped islands are obtained from x-ray diffraction reciprocal space maps and from iso-strain scattering combined with anomalous scattering at the Ge K-edge. From reciprocal space maps around asymmetric Bragg reflections, also the properties of capped islands are obtained, giving insight into the structural changes during capping of SiGe islands with Si.