Initial stage of the overgrowth of InP on InAs∕InP(001) quantum dots: Formation of InP terraces driven by preferential nucleation on quantum dot edges

Abstract

This letter reports on the growth mechanism of the InP cap layer over InAs∕InP quantum dots (QDs) fabricated by metal organic vapor phase epitaxy (MOVPE). QD edges are shown to act as preferential nucleation sites for the InP cap layer, leading to the formation of InP domains around the nanostructures. As∕P exchange reactions are at the origin of the planarization of the top of the QDs under P-rich ambient, thus leading to a final QD height equal to the local thickness of the InP cap layer. The possibility to use As∕P exchange reactions to homogenize the height distribution of MOVPE grown InAs∕InP QDs is discussed on the basis of these observations.