Optical properties of in situ annealed InAs/GaAs quantum dots
Abstract
This work investigates the effect of in situ annealing on the size distribution of MBE-grown InAs/GaAs quantum dots (QDs) by photoluminescence (PL) measurements. In situ annealed QDs exhibit two distinct PL peaks as compared to that of the unannealed QDs, exhibiting only one peak. The annealed sample has a peak at smaller wavelength (blue-shifted) and with narrower FWHM suggesting higher degree of uniformity in size. The blue-shift is attributed to more dominant increase in Ga content of the QDs through In/Ga interdiffusion, which occurs during annealing. Thus, annealing increases the size of QDs, but more dominantly, also increases the Ga content producing a blue-shift in PL spectrum. The increase in dot size and In/Ga interdiffusion were further verified by Raman spectroscopy.