Selective area growth of InAs quantum dots formed on a patterned GaAs substrate

We describe the growth and characterization of InAs quantum dots (QDs) on a patterned GaAs substrate using metalorganic chemical vapor deposition. The QDs nucleate on the (001) plane atop GaAs truncated pyramids formed by a thin patterned SiO2 mask. The base diameter of the resulting QDs varies from 30 to 40nm depending on the size of the mask. With specific growth conditions, we are able to form highly crystalline surface QDs that emit at 1.6μm under room-temperature photopumped conditions. The crystalline uniformity and residual strain is quantified in high-resolution transmission electron microscopy images and high-resolution x-ray reciprocal space mapping. These strained QDs may serve as a template for selective nucleation of a stacked QD active region.