Optical properties of multi-stacked InAs quantum dots embedded in GaAs/InGaAs strained layer and its annealing behaviors

Multi-stacked InAs QDs embedded in ten periods of GaAs/Ino.1Gao. ₉As strained layers were grown by MBE and their optical properties were investigated by using PL spectroscopy. For the QDs embedded in ten periods of GaAs/Ino.₁Gao.₉As strained layers, the PL intensity is enhanced about 4.7 times and a narrower FWHM of 26 meV is observed compared to those of the conventional multi-stacked QDs. The PL spectra of the InAs QDs show blue-shifts of about 50 meV with increasing annealing temperature up to 85O°C At annealing temperature of 600°C, the FWHM of the PL peak is reduced to 16 meV and PL intensity is enhanced compared to those of the as-grown sample, which indicates improvement of size uniformity and crystal quality of the QDs.