Optical properties of InAs quantum dots grown on InP substrates

InAs quantum dots (QD's) grown on InP substrates are one of the promising materials systems for 1.5.5-mum optical communication devices and QD infrared photodetectors. Compared to the InAs/GaAs pair, InAs/InP has a smaller (3.2 %) lattice mismatch, resulting in the formation of relatively larger QD's. We have studied the optical properties of the InAs/InP QD's using photoluminescence measurements. The dependence of the optical properties on the growth conditions, including growth temperatures, doping, and GaAs overlayers, is systematically investigated. It is found that there is an optimal temperature to obtain the maximum QD density, due to the competition between the surface diffusion and the As/P exchange reaction.