Effect of Sn for the dislocation-free SiSn nanostructure formation on the vapor-liquid-crystal mechanism

Structures with tin-rich island arrays on silicon pedestals were obtained by molecular beam epitaxy using Sn as a catalyst for the growth of nanostructures. A tin island array was used further to study the growth of nanostructures in the process of Si deposition on the surface with Sn islands. It was established that, during the growth on the vapor-liquid-crystal mechanism, tin-rich islands are formed on faceted pedestals. A nanostructured cellular surface was formed between the islands on pedestals. The analysis of the elemental composition of the obtained nanostructures was performed by the methods of energy dispersive X-ray spectroscopy and photoelectron spectroscopy. It is shown that tin-rich islands can contain up to 90% tin, whereas the pedestal consists of silicon. The transmission electron microscopy data demonstrated a distinct crystal structure of tin-rich islands and silicon pedestals, as well as the absence of dislocations in the structures with island arrays on the faceted pedestals. The facet tilt angle is 19 degrees and corresponds to the (311) plane. The photoluminescence signal was observed with a photoluminescence maximum near the wavelength of 1.55 mu m.