Picosecond Nonlinear Relaxation of Photoinjected Carriers in a Single GaAs/AlGaAs Quantum Dot

TL;DR

This study uses picosecond-resolved spectroscopy to investigate the nonlinear relaxation dynamics of photoinjected carriers in a single GaAs/AlGaAs quantum dot, revealing carrier relaxation times and the role of carrier-carrier scattering.

Contribution

It provides a quantitative model of multiexciton relaxation in a single quantum dot, linking experimental data with relaxation mechanisms.

Findings

Carrier relaxation time depends on photoinjected carrier population.

Intra-dot carrier relaxation is enhanced by carrier-carrier scattering.

Multiexciton emission spectra vary with delay time and excitation intensity.

Abstract

Photoemission from a single self-organized GaAs/AlGaAs quantum dot (QD) is temporally resolved with picosecond time resolution. The emission spectra consisting of the multiexciton structures are observed to depend on the delay time and the excitation intensity. Quantitative agreement is found between the experimental data and the calculation based on a model which characterizes the successive relaxation of multiexcitons. Through the analysis we can determine the carrier relaxation time as a function of population of photoinjected carriers. Enhancement of the intra-dot carrier relaxation is demonstrated to be due to the carrier-carrier scattering inside a single QD.