Electronic structure and phonon-assisted luminescence in self-assembled quantum dots

We present photoluminescence (PL) measurements on an ensemble of InAs/GaAs self-assembled quantum dots embedded in GaAs. We observe a transition from an inhomogeneously broadened photoluminescence band under non-resonant exci tation into up to five phonon-assisted bands under selective excitation. We interpret the phonon-assisted PL as being indicative of an enhanced electr on-phonon interaction. We also perform theoretical calculations of the sing le-particle energy spectrum of self-assembled quantum dots, in the framewor k of the single-band effective-mass approximation for electrons and using t he Luttinger Hamiltonian for holes. Finally, by taking advantage of the com puted wave functions we evaluate the Huang-Rhys parameter: We find an enhan cement of the electron-phonon interaction that partially accounts for the e xperimental re suits.