Suppression of InAs∕GaAs quantum dot decomposition by the incorporation of a GaAsSb capping layer

Abstract

The influence of a GaAsSb capping layer on the structural properties of self-assembled InAs∕GaAs quantum dots (QDs) is studied on the atomic scale by cross-sectional scanning tunneling microscopy. QDs capped with GaAs0.75Sb0.25 exhibit a full pyramidal shape and a height more than twice that of the typical GaAs-capped QDs, indicating that capping with GaAsSb suppresses dot decomposition. This behavior is most likely related to the reduced lattice mismatch between the dot and the capping layer.