Systematic study of carrier correlations in the electron-hole recombination dynamics of quantum dots

TL;DR

This study investigates how carrier interactions influence electron-hole recombination in quantum dots, revealing non-exponential decay behaviors and conditions for mono-exponential decay, supported by microscopic theory.

Contribution

It provides a systematic analysis of carrier correlation effects on recombination dynamics in quantum dots with varying design parameters.

Findings

Decay is generally non-exponential, but can be mono-exponential under specific conditions.

Resonant excitation significantly shortens luminescence decay time.

Results align with a microscopic theory explaining deviations from simple models.

Abstract

The ground state carrier dynamics in self-assembled (In,Ga)As/GaAs quantum dots has been studied using time-resolved photoluminescence and transmission. By varying the dot design with respect to confinement and doping, the dynamics is shown to follow in general a non-exponential decay. Only for specific conditions in regard to optical excitation and carrier population, for example, the decay can be well described by a mono-exponential form. For resonant excitation of the ground state transition a strong shortening of the luminescence decay time is observed as compared to the non-resonant case. The results are consistent with a microscopic theory that accounts for deviations from a simple two-level picture.