In-plane self-arrangement of high-density InAs quantum dots on GaAsSb/GaAs(001) by molecular beam epitaxy

摘要

InAs quantum dots (QDs) were grown on GaAsSb/GaAs(001) buffer layers by molecular beam epitaxy using a Stranski-Krastanov mode. A high QD density of about 1 X 10~(11) cm~(-2) was obtained for an Sb flux ratio of more than 0.14. In the case of high-density QD growth on the GaAsSb layers, many nanoholes were observed on the surface and located beside the QDs. In addition, one-dimensional QD chains were formed near nanogrooves and step edges. As the InAs growth proceeded, an in-plane arrangement of the InAs QDs was partially formed along < 010 > directions. It is considered that the in-plane arrangement of the QDs originates from the QD chains and the nanogrooves, aligned along < 010 > step edges. From transmission electron microscopy and photoluminescence measurements, it was found that the high-density InAs QDs on the GaAsSb buffer layer reveal high crystal quality.