Microphotoluminescence spectroscopy of CdSe quantum dots grown on vicinal-surface and exact-orientation substrates

We investigated the optical properties of CdSe quantum dots (QDs) grown by molecular-beam epitaxy on GaAs substrates using micro-photolunrinescence spectroscopy. Comparison was made between the QDs Grown on a substrate with a vicinal tilt of 2degrees in the [111] direction and those on an on-axis substrate. We have studied the evolution of lineshapes of QD photoluminescence spectra under the improved condition of spatial resolution. It was found that the use of a substrate with the vicinal surface leads to the suppression of excitonic PL emitted from a wetting layer. The PL studies revealed that the thermo-stability up to 150 K was obtained in the sample on the on-axis substrate, whereas rapid temperature-induced quenching starting from 6 K was observed in that grown on the vicinal substrate.