Dependence of the InAs size distribution on the growth times for vertically stacked InAs/GaAs quantum dots

Abstract

Vertically stacked InAs/GaAs quantum dots (QDs) were grown on (001) GaAs substrates by using molecular beam epitaxy (MBE). The dependence of the InAs quantum-dot size distribution on the growth time of InAs/GaAs QDs was investigated by using atomic force microscopy (AFM), transmission electron microscopy (TEM), and photoluminescence (PL) measurements. AFM and TEM images showed that the size of the QDs increased with increasing number of stacked layers when the growth time of the InAs QDs was held constant. However, the size distribution uniformity of the QDs was improved when the deposition time of the InAs QDs gradually decreased while the number of stacked layers increased. These results can help improve understanding of how to control the sizes of the QDs in InAs/GaAs QD arrays.