Femtosecond mid-infrared study of electron dynamics in InAs/InAlAs quantum dots

We present pump-mid-infrared-probe measurements in InAs/InAlAs self-organized quantum dots allowing to isolate the electron dynamics. By tuning the probe to an intraband transition in the conduction band at 13 μm, we measured a characteristic time of 3 ps for the electron capture from the barrier to the ground state of the dots at low excitation densities. At higher densities, this capture time decreases to 1.5 ps indicating the contribution of Auger-like processes.