A transmission electron microscopy and reflection high-energy electron diffraction study of the initial stages of the heteroepitaxial growth of InSb on GaAs (001) by molecular beam epitaxy

I n situ reflection high-energy electron diffraction and cross-sectional and plan-view transmission electron microscopy have been used to investigate the initial stages of InSb growth on GaAs(001), by molecular-beam epitaxy. Growth of the InSb commences with the formation of rectangular-based islands, having flat tops and sloping sides, with facets on certain planes of types {111} and {113}. The islands show near normal lattice spacings, with no significant straining. As deposition proceeds, islands coalesce and, after the equivalent of 40 monolayers of deposition, form a connected network. Complete coverage of the GaAs substrate is achieved after ≂300 monolayers of deposition. This places a lower limit on the thickness of InSb layers, which may be considered in the design of optoelectronic devices.