Ultrafast Carrier Activation in Resonantly Excited 1.3 (*mu InAs/GaAs Quantum Dots at Room Temperature

Carrier activation dynamics is measured in self-assembled InAs/GaAs quantum dots with a high degree of electronic state symmetry, at room temperature and following resonant excitation in the ground state. Carriers are activated to the first excited state on a 15-ps time scale in the low-excitation regime, and the total activation rate increases quadratically with the fractional dot occupation. Electron-hole interaction is identified as the dominant mechanism of electron scattering within the lowest confined states of a single quantum dot, circumventing the observation of a phonon bottleneck.