Picosecond time-resolved bleaching dynamics of self-assembled quantum dots

Picosecond bleaching dynamics of vertically stacked self-assembled quantum dots is investigated by means of time-resolved pump-probe differential reflection spectroscopy at room temperature. This allows us to study the dynamics of the pump generated carriers within the quantum dots. We observe that the absorption spectrum is shifted over 12 meV with respect to the photoluminescence spectrum. From the time-resolved measurements we detect that the carrier lifetime within the dots strongly depends on the energy within the absorption spectrum.