Effect of arsenic species on the formation of (Ga)InAs nanostructures after partial capping and regrowth

Abstract

Surface morphologies of self-assembled (Ga)InAs nanostructures grown by partial-capping-and-regrowth technique using gas-source molecular beam epitaxy (GSMBE) and solid-source molecular beam epitaxy (SSMBE) are compared. With SSMBE under an As4 ambient, as-grown quantum dots (QDs) change to a camel-like nanostructure after being partially overgrown with GaAs. When additional InAs is deposited, quantum-dot molecules are created. In comparison, with GSMBE under As2 overpressure, as-grown QDs are transformed into quantum rings after partial capping with GaAs and then, after regrowth, become double QDs. At higher regrowth temperature, QD rings are formed.