Biexciton and exciton dynamics in single InGaN quantum dots

Abstract

Time-resolved and time-integrated microphotoluminescence spectrometry of exciton and biexciton transitions in a single self-assembled InGaN quantum dot gives sharp peaks, with the biexciton 41 meV higher in energy. Theoretical modelling in the Hartree approximation (using a self-consistent finite difference method) predicts a splitting of up to 51 meV. Time-resolved microphotoluminescence measurements yield a radiative recombination lifetime of 1.0 ± 0.1 ns for the exciton and 1.4 ± 0.1 ns for the biexciton. The data can be fitted to a coupled DE rate equation model, confirming that the exciton state is refilled as biexcitons undergo radiative decay.