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Strained Si1−xSnx (0.001≤x≤0.052) alloys were synthesized on (001) Si substrates by molecular beam epitaxy at 220 and 280 °C. The as-grown alloys were found to be pseudomorphic to Si with no indication of extended defects and tin precipitates. Within the accuracy of our studies the compressive strain in the alloys corresponds to that deduced from Vegard’s linear interpolation between the lattice parameters of Si and α-Sn. The annealing experiments show that the alloys are thermally unstable at a higher temperature (1000 °C) and that the transition of the Si1−xSnx/Si system to a lower energy state occurs through two channels: (i) alloy decomposition through precipitation of tin atoms into metallic β-Sn, and (ii) introduction of 60° misfit dislocations.

The capability of misfit dislocations to generate nanostructures in the bulk of Si1−xGex/Si heteroepitaxial systems is demonstrated. It is shown that dislocation slip originating from compositionally graded Si1−xGex layers can produce a range of low-dimensional structures including nanowires, nanodots, and mosaic superlattices. Formation of the nanostructures is achieved in parallel processing, through a simple two-step cycle which includes growth of layered planar structures and postgrowth annealing.

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