Parametric Study on the Growth of Type-II InSb Quantum Dots on InAs Substrates by Molecular Beam Epitaxy

The formation of InSb quantum dots (QDs) embedded in an InAs matrix grown by molecular beam epitaxy (MBE) was studied parametrically. In particular, the effect of the sequence of the change of As2 dimers and Sb2 on the distribution of As and Sb at the InSb-QDs/InAs interface was investigated by cross-sectional transmission electron microscopy (TEM). It was shown that additional As2 above the InSb QDs results in the disappearance of InSb, while additional Sb2 enhances the size of the InSb QDs. The specific growth method, Stranski–Krastanov (S–K) or migration-enhanced epitaxy (MEE), also affects the shape of the QDs. The cross-sectional TEM images were investigated with geometrical phase analysis (GPA) as a function of the InSb coverage. Photoluminescence spectroscopy on samples comprising 21 stacked InSb QD layers revealed a strong emission peak at about 4 μm (77 K).