Blue-shift emission in InP-based quantum dots by SiO2 sputtering and rapid thermal annealing

We have investigated the atomic-intermixing effect in In(Ga, Al)As/InP quantum dots (QDs) by tuning the group III compositions. The QDs including InAs, In0.95Al0.05As, and In0.95Ga0.05As were embedded in In0.52Al0.48As matrix. The intermixing process includes the deposition of a sputtered SiO2 layer on the sample surface and a subsequent rapid thermal annealing (RTA) at temperature between 700 and 800 °C. From the room-temperature photoluminescence data, InAs and In0.95Al0.05As QDs show similar wavelength tuning behavior against the RTA temperature. In0.95Ga0.05As QDs exhibit an extra amount of wavelength blue-shift, and have a maximum blue-shift of 281 nm at a RTA temperature of 800 °C. The results suggest an enhanced atomic-intermixing effect by the presence of Ga atoms.