Effect of annealing on the microstructural and optical properties of InAs quantum dots grown on GaAs buffer layers

Abstract

The effect of thermal annealing on self-assembled InAs/GaAs quantum dots (QDs) has been investigated by using transmission electron microscopy (TEM) and photoluminescence (PL) measurements. The TEM images showed that the lateral size and density of the InAs QDs were not changed significantly up to 700 degreesC. When the InAs/GaAs QDs were annealed at 750 degreesC, while the lateral size of the InAs QDs increased, their density decreased. The InAs QDs disappeared due to annealing at 850 degreesC. PL spectra showed that peaks corresponding to the interband transitions of the InAs QDs shifted slightly towards the high-energy side and that the full width at half maximum of the peak decreased with an increase in annealing temperature. The behavior of the PL peak was attributed to interdiffusion between the InAs QDs and the GaAs capping layer. These results can help to give an improved understanding of the effect of thermal annealing on the microstructural and optical properties of InAs/GaAs QDs.