ENHANCED ANTI-STOKES PHOTOLUMINESCENCE IN A GAAS AL0.17GA0.83AS SINGLE-QUANTUM-WELL WITH GROWTH ISLANDS/

Photoluminescence spectra of a GaAs/Al0.17Ga0.83As single quantum well with growth islands are investigated in the Stokes as well as in the anti-Stokes regime. While at 5 K only luminescence at energies below t he excitation energy can be detected, above 20 K also anti-Stokes lumi nescence is observed. A rate-equation model reproduces the observed de pendence of the intensities of Stokes and anti-Stokes luminescence on temperature and, qualitatively, on the areal density of the growth isl ands and the properties of the diffusion-assisted transfer between the m. The geometrical properties can enhance the anti-Stokes luminescence by almost one order of magnitude.