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

Abstract

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 1×1011 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.