Ex-situ control of fine-structure splitting and excitonic binding energies in single InAs/GaAs quantum dots

TL;DR

This study demonstrates how annealing systematically alters the electronic properties of single InAs/GaAs quantum dots, notably reducing fine-structure splitting and significantly changing excitonic binding energies, through wavefunction modifications.

Contribution

It provides the first detailed analysis of how annealing affects the fine-structure splitting and excitonic energies in individual quantum dots.

Findings

Fine-structure splitting decreases with annealing.

Excitonic binding energies change dramatically.

Wavefunction shapes and positions are altered by annealing.

Abstract

A systematic study of the impact of annealing on the electronic properties of single InAs/GaAs quantum dots (QDs) is presented. We are able to record single QD cathodoluminescence spectra and trace the evolution of one and the same QD over several steps of annealing. A systematic reduction of the excitonic fine-structure splitting is reported. In addition the binding energies of different excitonic complexes change dramatically. The results are interpreted in terms of a change of electron and hole wavefunction shape and mutual position.