X-ray methods for strain and composition analysis in self-organized semiconductor nanostructures

The fabrication of low-dimensional nanostructures (e.g. quantum wires or quantum dots) is presently among the most exciting challenges in semiconductor technology. The electronic and optical properties of these systems depend decisively on structural parameters, such as size, shape, elastic strain, chemical composition and positional correlation among the nanostructures. X-ray scattering methods have proven to be an excellent tool to get access to these parameters. Beyond its sensitivity to deformations of the crystal lattice, it is sensitive to fluctuations of the surface and interface morphology on length scales ranging from 0.1 nm up to several μm. The small dimensions and the corresponding weak scattering signal require the use of highly brilliant synchrotron radiation. Recent methodological developments and their application to the material system Ge on Si are discussed.