Emission and HR-XRD study of InGaAs/GaAs quantum wells with InAs quantum dots grown at different temperatures

摘要

GaAs/In_(0.15)Ga_(0.85)As/GaAs QWs with embedded InAs QDs grown at different temperatures have been studied by means of the photoluminescence (PL), X ray diffraction (XRD) and high resolution XRD (HR-XRD) methods. PL study has detected varying of QD parameters and HR-XRD permits monitoring the QW parameters. It is shown that increasing the QD growth temperature up to 510 ℃ leads to raising the QD sizes, to shift of QD emission peak to low energy and increasing the PL intensity of QDs. Simultaneously Ga/In atom intermixing is realized mainly between the InGaAs buffer and InAs wetting layers and did not influent on the InAs QD composition. At higher QD growth temperatures (525-535 ℃) the PL intensity of QDs decreases significantly together with decreasing the QD heights and the shift of PL peaks into higher energy. Fitting the HR-XRD results has revealed that Ga/In atom intermixing involves the composition changes in buffer and wetting layers, as well as in QDs. The mentioned optical and structural effects have been discussed in details.