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

Many-body effects on the exciton spectra of self-organized InAs/GaAs quantu m dots (QD's) are investigated in high-density photoluminescence experiment s. Opposite renormalization of the ground- and excited-state transition ene rgies is observed with increasing exciton occupation of the QD's. The groun d-state transition energy decreases by similar to 16 meV whereas the excite d-state transition energies increase up to similar to 26 meV for an average occupation with 18 excitons corresponding to a volume density of similar t o2 X 10(19) cm(-3). The shrinkage of the ground-state transition energy nor malized to the exciton binding energy is significantly smaller than band-ga p renormalization in higher dimensional systems supporting the strong confi nement in the self-organized InAs/GaAs QD's.