Si-GaAs (001) superlattice structure

We examined the structural properties of Si layers embedded in GaAs and AlAs-GaAs structures by means of X-ray diffraction and transmission electron microscopy to identify growth parameters for the synthesis of Si-GaAs superlattices. We find that localized pseudomorphic Si layers can be obtained by molecular beam epitaxy at 500-540°C up to a thickness of 7-8 monolayers. Fifteen period Si-GaAs(001) superlattices involving Si layers 2-3 monolayer thick were then synthesized using the same growth parameters. X-ray diffraction measurements and Raman spectroscopy studies confirm that pseudomorphic growth and relatively abrupt interfaces were achieved.