Fabrication of InAs quantum ring nanostructures on GaSb by droplet epitaxy

In this article, we report the formation of InAs quantum ring nanostructures (QRNs) on GaSb (0 0 1) surface by droplet epitaxy (DE) mode using molecular beam epitaxy. We examined the impact of various growth conditions, including substrate temperature (Ts), As2 beam equivalent pressure (BEP) and surface stoichiometry, on the shape, density and size of the InAs QRNs. We confirmed that the InAs QRNs have better rotational symmetry at relatively high Ts and low As2 BEP. The symmetry of the QRN is due to the isotropic indium (In) out-migration along [1 1 0] and [1 −1 0], controlled via change in stoichiometry (surface As coverage) with temperature and the As2 BEP. These results indicate that we can realize InAs QRN on GaSb surface by DE process.