Effects of rapid thermal annealing on structure and luminescence of self-assembled InAs/GaAs quantum dots

Postgrowth rapid thermal annealing was used to modify the structural and optical properties of the self-assembled InAs quantum dots grown on GaAs substrates by molecular beam epitaxy. It is found that significant narrowing of the luminescence linewidth (from 78.9 to 20.5 meV) from the InAs dot layer occurs together with about 260 meV blueshift at annealing temperatures up to 850 °C. Observation of high-resolution transmission electron microscopy shows the existence of the dots under lower annealing temperatures but disappearance of the dots annealed at 850 °C. The excited-state-filling experiments for the samples show that the luminescence of the samples annealed at 850 °C exhibits quantum well-like behavior. Comparing with the reference quantum well, we demonstrate significant enhancement of the interdiffusion in the dot layer.