Multi-Exciton Spectroscopy of a Single Self Assembled Quantum Dot

TL;DR

This study uses low temperature confocal microscopy to analyze a single quantum dot, revealing weak single exciton emission and complex multiexcitonic transitions, with implications for quantum dot optical properties.

Contribution

It provides the first detailed spectroscopic analysis of a single self-assembled quantum dot, combining experimental data with a many-body theoretical model.

Findings

Single exciton emission is very weak.

Sharp spectral lines originate from multiexcitonic states.

Broad bands appear when states with continuum electrons are occupied.

Abstract

We apply low temperature confocal optical microscopy to spatially resolve, and spectroscopically study a single self assembled quantum dot. By comparing the emission spectra obtained at various excitation levels to a theoretical many body model, we show that: Single exciton radiative recombination is very weak. Sharp spectral lines are due to optical transitions between confined multiexcitonic states among which excitons thermalize within their lifetime. Once these few states are fully occupied, broad bands appear due to transitions between states which contain continuum electrons.