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
.