Structure and optical properties of Si/InAs/Si layers grown by MBE on Si substrate at different temperatures

Epitaxial Si/InAs/Si heterostructure grown on (001) Si substrate by molecular beam epitaxy (MBE) and annealed at 800 degreesC, and 880 degreesC were investigated by High Resolution Transmission Electron Microscopy (HRTEM). Extensive interdiffusion at 800 degreesC leads to the formation of an InAs solid solution as well as InAs-enriched regions with extensions of similar to 6nm, which exhibit two kinds of ordering. The ordering of InAs molecules occurred, respectively, in {110} planes inclined and 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 grown at 800 degreesC shows photoluminescence in the 1.3 mum region, which is tentatively attributed to the recombination of excitons localised in the ordered regions.