Enhanced polar exciton-LO-phonon interaction in quantum dots

Phonon-assisted exciton transitions in self-organized InAs/GaAs quantum dot s (QDs) are investigated by photoluminescence (PL) and PL excitation spectr oscopy. An unexpectedly enhanced polar exciton-LO-phonon interaction for su ch strained low-symmetry QDs is found. Calculations in the adiabatic approx imation 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 i n zero-dimensional systems.