Controlled Growth of InAs/GaAs Nanostructures by Droplet Epitaxy

Abstract

In(Ga)As low-dimensional structures have wide applications from lasers to single photon emitters. Here, we demonstrate the controlled growth of InAs dots and rings on GaAs (100) by the droplet molecular beam epitaxy. At high temperature the InAs large dots with low density are formed by the crystallization of the low density indium droplets. The optical quality of the dots is improved because of the high temperature growth. While for low temperature growth, the morphology is governed by the interplay between the migration of surface indium adatoms and their crystallization that occurs inside and at the edge of the droplets. The high density InAs small dots are formed spontaneously by relaxing the mismatch strain. The discovery ameliorates In(Ga)As nanostructures for various applications by optimizing the growth conditions during droplet molecular beam epitaxy.