Effects of material intermixing on electronic energy levels in Ga(As)Sb/GaAs quantum dots

The paper reports an theoretical investigation on the effects of material intermixing in epitaxial Ga(As)Sb/GaAs quantum dots (QDs). Conditions of type-II band alignment of Ga(As)Sb/GaAs is considered. The fabrication of Ga(As)Sb/GaAs QDs by molecular beam epitaxy is briefly described. Finite element analysis of strain in and around QD is performed. Strain-induced bandgap modification is considered for calculating the discrete energy levels in QDs. Effects of As-Sb intermixing in QD are quantified for different dot sizes (height and diameter). Comparison between calculated result and spectroscopic data suggests that the degree of intermixing is quite high. The estimated As content in nominally grown GaSb QD, is between 55 and 85%.