Molecular Beam Epitaxy of Strained Nanoheterostructures Based on Si, Ge, and Sn

The results of investigating the generation of strained nanoheterostructures based on compounds with materials of group IV (Ge, Si, Sn) are presented. It is established how silver, tin, and lead atoms diffuse over the surface and what temperature dependences of diffusion coefficients are specific to atoms of these elements. It is shown that the diffusion of silver, tin, and lead atoms follows the mechanism of solid-phase wetting with generation of surface phases. The experimental data are provided that indicate the dominating role of edge dislocations and dislocation complexes of edge type in relaxation of Ge/Ge0.5Si0.5/Si(001) heterostructure. Tin-rich islands with Si pedestal on Si(001) substrate were obtained by the molecular beam epitaxy method. Firstly, the Sn film was applied on the Si surface. During the subsequent annealing an array of Sn islands, which were further used as catalysts for growing nanoobjects, was formed. Tin-rich islands with Si pedestal are formed after deposition of silicon at temperatures of 300-450 degrees C on the surface with Sn islands. The growth of islands with pedestal occurred by the vapor-liquid-crystal mechanism. Intense photoluminescence was revealed from the tin-rich islands with Si pedestals in the wavelength range 1.3-1.7 mu m.