Si1 − x Ge x /Si heterostructures grown by molecular-beam epitaxy on silicon-on-sapphire substrates

Abstract

The growth of heterostructures with Si1 − xGex layers on \(\left( {1\bar 102} \right)\) sapphire substrates by molecular-beam epitaxy with a silicon sublimation source and a germanium gas source (GeH4) is reported. The systematic study of the influence of substrate temperature and thickness of the silicon buffer layer shows that the optimal conditions for growing epitaxial Si1 − xGex layers are provided at a temperature of TS = 375–400°C. There are significant differences in the orientations of Si1 − xGex layers, depending on the thickness d of the Si buffer layer: the preferred orientations are (100) at d ≥ 100 nm and (110) for thinner layers. Heterostructures with thick (∼1 μm) Si1 − xGex layers, doped with erbium atoms, exhibit intense photoluminescence at λ = 1.54 μm.