Photoluminescence spectroscopy of trions in quantum dots: a theoretical description

TL;DR

This paper provides a theoretical analysis of trion recombination in quantum dots, highlighting how size and charge type influence photoluminescence, and confirms the importance of correlations in the valence band through comparison with experiments.

Contribution

It offers a comprehensive configuration interaction model for trion recombination in quantum dots, including effects of temperature and wavefunction ratios, aligning with experimental observations.

Findings

Recombination rate enhancement is suppressed for negative trions with increasing dot size.

Recombination rate enhancement is reversed for positive trions with increasing dot size.

Correlations in the valence band are crucial for understanding photoluminescence spectra.

Abstract

We present a full configuration interaction study of the spontaneous recombination of neutral and singly charged excitons (trions) in semiconductor quantum dots, from weak to strong coupling regimes. We find that the enhancement of the recombination rate of neutral excitons with increasing dot size is suppressed for negative trions, and even reversed for positive trions. Our findings agree with recent comprehensive photoluminescence experiments in self-assembled quantum dots [P. Dalgarno et al. Phys. Rev. B {\bf 77}, 245311 (2008)] and confirm the major role played by correlations in the valence band.The effect of the temperature on the photoluminescence spectrum and that of the ratio between the electron and hole wavefunction lengthscales are also described.