Bandgap renormalization and carrier relaxation in self-organized InAs quantum dots

Strong many-body effects have been observed in time-resolved photoluminescence spectroscopy of self-organized InAs/GaAs quantum dots. Our results show that the effects generate considerable bandgap renormalization, being 28 meV at a dot occupancy of similar to 20 electron-hole pairs for the lowest transition. It is also found that many-particle state scattering gives rise to a large homogeneous broadening of the photoluminescence peak, from which we estimate the intradot relaxation time to be 300 fs. It is determined by direct time-resolved measurements that the electron intradot relaxation time is no longer than 1.5 ps