Structure and optical properties of Si/InAs/Si layers grown by molecular beam epitaxy on Si substrate

Epitaxial Si/InAs/Si heterostructure grown on (001) Si substrate by molecular beam epitaxy and annealed at $800 °C$ was investigated by high resolution transmission electron microscopy. Extensive interdiffusion leads to the formation of an InAs solid solution in the Si cap layer. Additionally, InAs-enriched regions with extensions of $∼6 nm,$ which exhibit two kinds of ordering are observed. The ordering of InAs molecules has occurred, respectively, in (101) and $(101̄)$ planes inclined and (110) and $(11̄0)$ planes parallel to the [001] growth direction. It is attributed to the energy gain from the reduced number of mixed Si–As and Si–In bonds. The sample show photoluminescence in the 1.3 μm region, which is tentatively attributed to the recombination of excitons localized in the ordered regions.