Ultrafast relaxation dynamics in strain-induced quantum dots

We perform time‐resolved photoluminescence experiments to study carrier relaxation in strain‐induced (GaIn)As quantum dots. A sub‐picosecond onset of the photoluminescence from the lowest quantum‐dot transition after optical excitation of higher‐energetic barrier states is observed, which shows that carrier capture into the quantum‐dot ground state can be extremely fast at high carrier densities. The recombination lifetime of the lowest quantum‐dot transition and the interlevel relaxation time are extracted from the photoluminescence decay.