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

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 1x1011 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