Enhanced Polar Exciton-LO-Phonon Interaction in Quantum Dots

Phonon-assisted exciton transitions in self-organized InAs/GaAs quantum dots (QDs) are investigated by photoluminescence (PL) and PL excitation spectroscopy. An unexpectedly enhanced polar exciton-LO-phonon interaction for such strained low-symmetry QDs is found. Calculations in the adiabatic approximation indicate that the particular quantum confinement and piezoelectric effect together account for the enhanced coupling. The results provide new insights into the long-standing problem of the exciton-phonon interaction in zero-dimensional systems.