OPTICAL SPECTROSCOPY OF SELF-ASSEMBLED TYPE-II GASB GAAS QUANTUM-DOT STRUCTURES GROWN BY MOLECULAR-BEAM EPITAXY/

We report an optical spectroscopic study of GaSb/GaAs quantum dots (QD s) formed by the Stranski-Krastanow growth mode using molecular beam e pitaxy. We identify the QD luminescence by phololuminescence obtained at different excitation energies and densities. We show that, for thes e structures, not only the spectral position of peaks, but also their relative intensities are critically dependent upon the density of phot ogenerated carriers, Photoluminescence excitation (PLE) measurements c onfirm our assignment of the QD related peaks and a feature similar to 25-27 meV higher in energy than the PLE detection energy Is discussed in terms of phonon relaxation. (C) 1998 American Institute of Physics .