Rapid thermal annealing effects on self-assembled quantum dot and quantum ring structures

Low temperature photoluminescence spectroscopy is used to analyze the effects of the postgrowth thermal annealing on the electronic structure ad carrier dynamics of GaAs∕AlGaAs quantum dot and quantum ring structures grown by droplet epitaxy. All the samples show a large increase in the photoluminescence efficiencies after the thermal treatment due to sizeable reduction in the material defectivity. Modifications of the photoluminescence band, which depend on thermal annealing temperature, are found and quantitatively interpreted by means of a simple model based on the Al–Ga interdiffusion.