Intermixing of InGaAs quantum dots grown by cycled monolayer deposition

We investigate the thermal induced intermixing and the diffusion kinetics of InGaAs quantum dots grown by cycled monolayer deposition subjected to the overgrowth and ex situ annealing. The group-III intermixing, that obeys the Fickian law, reaches a steady state after ex situ annealing up to 850°C. An identical activation energy (E _a= 1.5±0.3 eV) obtained with and without subjecting to overgrowth implies that the intermixing is primarily governed by the dynamic annealing of intrinsic defects during the epitaxial overgrowth. The intrinsic intermixing is attributed to the instability of the interface morphology driven by the atomic migration during self-formation of quantum dot.