Efficient acoustic phonon broadening in single self-assembled InAs/GaAs quantum dots

We report systematic temperature-dependent measurements of photoluminescence excitation spectra in single self-assembled InAs/GaAs quantum dots. We studied the increase with temperature of the excited-state homogeneous linewidth for different quantum dots. We found a correlation between the acoustic phonon broadening efficiency and the background intensity in the photoluminescence excitation spectra. These results demonstrate the interaction of the discrete quantum dot excited states with a quasicontinuum of states and impose severe limitations on the isolated artificial macroatom scheme for a single quantum dot.