Grazing incidence x-ray scattering: an ideal tool to study the structure of quantum dots

We discuss the application of grazing incidence x-ray techniques to charact erize nanometer sized islands, which arise in strained layer heteroepitaxy of semiconductor systems ('quantum dots'). Using x-rays from synchrotron so urces, grazing incidence small angle scattering (GISAXS) is demonstrated to yield structural information on shape, size and lateral correlation. Resul ts on self-assembled Ge islands on Si(lll) substrate are shown as an exampl e. The crystalline properties of coherent quantum dots are obtained from gr azing incidence diffraction (GID). From the analysis of reciprocal space ma ps the interdependence of shape and elastic strain within the quantum dots is determined. We discuss results on coherent InAs quantum structures on Ga As(100).