Density Control of GaSb/GaAs Self-assembled Quantum Dots (∼25nm) Grown by Molecular Beam Epitaxy

Abstract
We report the realization of quantum-sized GaSb dots, of small diameter (∼25nm), on GaAs by molecular beam epitaxy in the Stranski-Krastanow growth mode. At the deposition of 3.1 mono-layer(ML) GaSb, the average diameter and height of GaSb quantum dot(QD) are 26 nm and 6.2 nm, respectively. In addition, the density control was systematically achieved between 2.6×109 to 1.2×1010cm-2 by carefully choosing the amount of GaSb deposited from 2.5 to 3.1ML. The growth mechanism are discussed in detail. These results are very useful in forming a QD of staggered band lineup (type-II) of possible use in novel device applications