Size-shrinkage effect of InAs quantum dots during a GaAs capping growth

The modification of the InAs quantum dots (QDs) by the GaAs capping growth was studied by using cross-sectional STEM and atomic force microscopy. In case of the GaAs capping growth at 450 °C, it was found that the lateral size of the InAs QDs significantly decreases rather than the height and that this size-shrinkage effect is enhanced for the large QDs. The shrinkage behavior is mainly attributed to the indium surface segregation, strongly depending on the surface strain of the QDs. The growth process of the GaAs capping layer plays an important role for achieving the size ordering of the embedded QDs.