Self-assembling molecular beam epitaxial growth of the InAs quantum dots embedded in deep Al0.5Ga0.5As barriers

Self-assembling molecular beam epitaxial growth of the InAs quantum dots (QDs) on Al0.5Ga0.5As was studied. In contrast to the InAs QDs grown on GaAs, the growth on Al0.5Ga0.5As was found to be difficult for the development of equishaped islands with strong exciton confinement at high temperatures. This difficulty was due to the adsorption of excess As molecules and impurity atoms on the Al0.5Ga0.5As surface from the growth background. By inserting 2.0 monolayers (ML) of GaAs between the InAs and the Al0.5Ga0.5As, however, narrowing of the size distribution and enhancement of the exciton confinement was obtained. Intense photoluminescence continuing to room temperature was achieved by applying this growth technique for the 2.4 ML InAs QDs in Al0.5Ga0.5As barrier.