InAs-Dot/GaAs Structures Site-Controlled by in situ Electron-Beam Lithography and Self-Organizing Molecular Beam Epitaxy Growth

Abstract

A novel site-control technique for InAs dot fabrication on GaAs has been demonstrated by a combination of in situ electron-beam (EB) lithography and self-organizing molecular beam epitaxy (MBE) using an ultrahigh-vacuum multichamber system. On an MBE-grown GaAs (001) surface, shallow holes of submicron size were patterned by in situ EB writing and Cl2 gas etching. By supplying more than 1.4 monolayer of InAs onto the patterned surface, In(Ga)As dots were preferentially self-organized in the holes, while dot formation around the holes was sufficiently suppressed, due to the selectivity of In atom incorporation in the (111)B-like slope in the hole. This indicates the usefulness of such a technique in fabricating arbitrarily arranged quantum-dot structures.