InAs-Dot/GaAs structures site-controlled by in situ electron-beam lithography and self-organizing molecular beam epitaxy growth

A novel site-control technique for InAs dot fabrication on GaAs has been demonstrated by a combination of ill 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 ill situ EB writing and Cl-2 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 rn 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.