Structural and optical properties of shape-engineered InAs quantum dots

Abstract

Shape-engineered InAs quantum dots (QDs) were grown by using thin In0.15Ga0.85As and a monolayer (ML) of InAs with different periods on 3 ML InAs QDs and their structural and optical properties were investigated by transmission electron microscopy (TEM), photoluminescence (PL), and photoreflectance (PR) spectroscopy. Cross-sectional TEM images of the QD samples showed that the shape, particularly the height of the QD, could be effectively controlled without any significant degradation in QD quality, such as the generation of dislocations in the QD, thus changing the optical properties. PL and PR spectra indicated that all the layers required for the formation of shaped-engineered QD were grown without any degradation in QD properties. PL spectra of shape-engineered QDs that had been subjected to rapid thermal annealing showed an abnormal behavior compared to those of conventionally grown InAs QDs.