Sb-mediated growth of high-density InAs quantum dots and GaAsSb embedding growth by MBE

Self-assembled high-density and high-uniformity InAs quantum dots (QDs) were grown on GaAs(001) substrates by antimony (Sb)-mediated molecular beam epitaxy technique using GaAsSb/GaAs buffer layer and InAsSb wetting layer (WL). In this Sb-mediated growth, many 2-dimentional (2D) small islands were formed on those WL surfaces. These 2D islands provide high step density and suppress surface migration. As the results, high-density InAs QDs were achieved, and photoluminescence (PL) intensity increased. In addition, the QD density could be widely controlled by adjusting Sb supply amount. Furthermore, by introducing GaAsSb capping layer (CL), higher PL intensity at room temperature was obtained as compared with that InGaAs CL.