Multi-excitonic complexes in single InGaN quantum dots

TL;DR

This paper investigates the optical properties of single InGaN quantum dots, revealing excitonic complexes, spectral diffusion, and carrier dynamics through cathodoluminescence spectroscopy.

Contribution

It presents the first detailed analysis of multi-excitonic complexes and carrier redistribution in single InGaN quantum dots using cathodoluminescence.

Findings

Identification of exciton and biexciton states

Observation of spectral diffusion correlating lines from the same quantum dot

Discovery of binding and anti-binding excitonic complexes

Abstract

Cathodoluminescence spectra employing a shadow mask technique of InGaN layers grown by metal organic chemical vapor deposition on Si(111) substrates are reported. Sharp lines originating from InGaN quantum dots are observed. Temperature dependent measurements reveal thermally induced carrier redistribution between the quantum dots. Spectral diffusion is observed and was used as a tool to correlate up to three lines that originate from the same quantum dot. Variation of excitation density leads to identification of exciton and biexciton. Binding and anti-binding complexes are discovered.