Effect of cap-layer growth rate on morphology and luminescence of InAs/InP(001) quantum dots grown by metal-organic vapor phase epitaxy

This work reports on the influence of the InP cap-layer growth rate on the structural and optical properties of InAs/InP quantum dots ( QDs ) grown by metal-organic vapor phase epitaxy. A careful correlation between the structural and optical properties of the QDs completed by a modeling of their interband transition energy evidences the presence of different QD families with heights varying by monolayer steps. The analysis of transmission electron microscopy images and photoluminescence spectra demonstrates a drastic decrease of the QD height during the growth of the InP cap layer, due to As/P exchange. The efficiency of this erosion mechanism is shown to be strongly related to the QD exposure time to PH3, depending on the growth rate of the InP cap layer. (c) 2006 American Institute of Physics.