Influence of p-doping on the temperature dependence of InAs/GaAs quantum dot excited state radiative lifetime

The radiative lifetime of the excited state transition of undoped and p-doped InAs/GaAs quantum dots (QDs) is estimated from measurements of time-integrated and time-resolved luminescence from both ground and excited states. The radiative lifetime of the undoped QDs increases from 500 ps at 10 K to almost 3 ns at room temperature, consistent with a Boltzmann redistribution of holes over the available energy states. The rate of increase can be suppressed by a factor of ∼2 by p-doping the QDs to maintain a hole population in the lowest confined dot states to high temperatures.