Radiative lifetimes in undoped and $p$-doped InAs/GaAs quantum dots

Radiative lifetimes in undoped and $p$ -doped InAs/GaAs quantum dots

Edmund Harbord, Peter Spencer, Edmund Clarke, and Ray Murray

Phys. Rev. B 80, 195312 – Published 13 November 2009

Abstract

We investigate the effect of $p$ doping on the luminescence properties of InAs/GaAs self-assembled quantum dots (QDs). Continuous-wave and time-resolved photoluminescence measurements are obtained as a function of temperature and used to extract the radiative lifetime of the QD ground state. We find that the low-temperature luminescence lifetime decreases from $\sim 1200$ to $\sim 700 ps$ for QDs doped with 0 and 10 holes/dot, respectively. The radiative lifetime of the undoped QDs increases monotonically with temperature and is consistent with Boltzmann spreading over dark states. The luminescence intensity from the heavily doped QDs changes much less with temperature compared with the undoped QDs and we attribute this to the presence of holes in ground states at higher temperatures.