Self-Formation of High-Density and High-Uniformity InAs Quantum Dots on Sb/GaAs Layers by Molecular Beam Epitaxy

Abstract

Self-assembled InAs quantum dots (QDs) grown on Sb/GaAs buffer layers by molecular beam epitaxy were investigated to achieve high-density and high-uniformity QDs. The density of InAs QDs on Sb/GaAs layers was markedly higher than that of InAs QDs on conventional GaAs layers. The high-density nucleation of three-dimensional (3D) InAs islands was attributed to the formation of two-dimensional (2D) wirelike structures prior to 3D islanding. QD density was controlled from 3×1010 to 1×1011 cm-2 by changing Sb supply amount. In addition, the density of very large dots due to coalescence increased with increasing Sb supply amount. On Sb (0.6 atomic layers)/GaAs buffer layers, we obtained high-density and high-quality InAs QDs, which revealed a narrow photoluminescence linewidth of about 30–35 meV.