Influence of intrinsic internal field on recombination kinetics of high coverage (N11) InAs/GaAs quantum dots

We present, by means of CW and time-resolved photoluminescence, a detailed experimental study of the optical properties of a large set of InAs self-assembled quantum dots grown on (N11)A/B GaAs substrates with different InAs coverages. Large variation of the external PL efficiency is observed, with a strong asymmetry between the A and B substrate termination. The analysis of PL time evolution leads us to exclude that the reduction of PL intensity would be associated to an increase of the non radiative recombination rates. The PL efficiency and decay times of the complete series of samples can be understood as a consequence of a large built-in electric potential associated with the piezoelectric field and permanent dipole moment inside the QDs.

We present, by means of cw and time-resolved photoluminescnce, a detailed experimental study of the optical properties of a large set of InAs self-assembled quantum dots grown on (N11)A/B GaAs substrates with different InAs coverages. Large variation of the external PL efficiency is observed, with a strong asymmetry between the A and B substrate termination. The analysis of PL time evolution leads us to exclude that the reduction of PL intensity would be associated to an increase of the non radiative recombination rates. The PL efficiency and decay times of the complete series of samples can be understood as a consequence of a large built-in electric potential associated to piezoelectric field and permanent dipole moment inside the QDs.