Selective, Maskless Growth of InSb on Selenium-Treated GaAs by Molecular Beam Epitaxy

Abstract

InSb nanoscale crystal islands were grown on a Se-terminated GaAs substrate by molecular beam epitaxy (MBE). In situ synchrotron radiation photoelectron spectroscopy studies for InSb island formation on this surface show that Sb atoms do not chemisorb directly onto the Se-terminated GaAs surface. The In overlayer is grown in a nearly laminar mode on the Se-terminated GaAs, and then Sb atoms diffuse across this surface until they bond to In or desorb. Consequently, InSb islands are formed. This islanding phenomenon is associated with the energy difference between the surface free energy of InSb and that of the Se-terminated surface, and with the strain energy due to the high lattice-mismatch stress. Furthermore, it is found that the InSb islands grown at 200° C have an average size of 30 nm and a density of the order of 1010 cm-2.