Decay dynamics of neutral and charged excitonic complexes in single InAs/GaAs quantum dots

TL;DR

This study investigates the decay dynamics of various excitonic complexes in single InAs/GaAs quantum dots through time-resolved measurements, revealing deviations from theoretical predictions and confirming specific transition time ratios.

Contribution

It provides systematic experimental data on excitonic decay times and compares them with theoretical models, highlighting the transition channel effects in quantum dot excitonics.

Findings

Measured decay time ratios for neutral complexes differ from theory

Identified exact match for charged exciton and biexciton decay ratios

Analyzed transition channels based on excitonic fine structure

Abstract

Systematic time-resolved measurements on neutral and charged excitonic complexes (X, XX, X+, and XX+) of 26 different single InAs/GaAs quantum dots are reported. The ratios of the decay times are discussed in terms of the number of transition channels determined by the excitonic fine structure and a specific transition time for each channel. The measured ratio for the neutral complexes is 1.7 deviating from the theoretically predicted value of 2. A ratio of 1.5 for the positively charged exciton and biexciton decay time is predicted and exactly matched by the measured ratio indicating identical specific transition times for the transition channels involved.