Self-organization processes in semiconductor heterostructures

Processes of self-organization during the epitactic growth of semiconductor heteroepitaxial systems represent a promising way for the fabrication of semiconductor nano-structures such as quantum wires and quantum dots. Two types of the self-organization processes can be used, namely a bunching of monolayer steps at a growing vicinal surface (step-bunching process) and an elastic relaxation of mismatched pseudomorphically grown epitaxial layer during the Stranski-Krastanow growth mode. The former mechanism can produce self-organized one-dimensional quantum wires, while the latter one can yield a nearly periodic array of self-organized quantum dots. Self-organized semiconductor nano-structures in superlattices can be observed by surface-sensitive x-ray scattering. Grazing incidence small angle scattering (GISAXS) detects the shape and the positions of the nano-structures, while grazing incidence diffraction (GID) is sensitive to the elastic strains in the nano-structures and in the surrounding crystal matrix. Therefore, combining both methods we can investigate both the shape and chemical composition of buried nano-structures. (Authors)