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Electrical and electronic engineering
The built-in strain and composition of as-grown and Si-capped single layers of Ge∕Si dots grown at various temperatures (460–800 °C) are studied by a comparative analysis of the Ge-Ge and Si-Ge modes in the polarized Raman spectra of the dots. A pronounced reduction of the strain and Ge content in the dots after deposition of the cap layer at low temperatures is observed, indicating that strain-induced Si diffusion from the cap layer is occurring. For large dots grown at 700–800 °C the observations are in agreement with a model of the Ge∕Si dot consisting of a Si-rich boundary region and a Ge-rich core.
Baranov, A.V., Fedorov, A.V., Persova, T.S., Moore, R.A., Yam, V., Bouchier, D., Le Thanh, V. and Kevin Berwick : Analysis of Strain and Intermixing in Single-Layer Ge/Si Quantum Dots Using Polarized Raman Spectroscopy. Physics Review B., Vol.73, 7, 2006. DOI:10.1103/PhysRevB.73.075322