Many-body effects on the optical spectra of InAs/GaAs quantum dots

Many-body effects on the exciton spectra of self-organized InAs/GaAs quantum dots (QD's) are investigated in high-density photoluminescence experiments. Opposite renormalization of the ground- and excited-state transition energies is observed with increasing exciton occupation of the QD's. The ground-state transition energy decreases by {~}16 meV whereas the excited-state transition energies increase up to {~}26 meV for an average occupation with 18 excitons corresponding to a volume density of ~2×10¹⁹cm^-3. The shrinkage of the ground-state transition energy normalized to the exciton binding energy is significantly smaller than band-gap renormalization in higher dimensional systems supporting the strong confinement in the self-organized InAs/GaAs QD's.