Heating by exciton and biexciton recombination in GaAs/AlGaAs quantum wells

TL;DR

This paper experimentally investigates exciton and biexciton recombination in GaAs/AlGaAs quantum wells, revealing their recombination times, effects on exciton temperature, and implications for Bose-Einstein condensation.

Contribution

It introduces a method to determine exciton temperature dynamics and demonstrates how recombination processes hinder exciton Bose-Einstein condensation in these systems.

Findings

Exciton recombination time is 16 ps.

Biexciton recombination time is 55 ps.

Recombination increases exciton temperature by up to 10 K.

Abstract

A comprehensive experimental investigation of exciton and biexciton recombination in GaAs/AlGaAs quantum wells is presented. Exciton and biexciton recombination times are found to be 16 and 55 ps, respectively. A method of determining the dynamics of the exciton temperature is developed. It is shown that both exciton and biexciton recombination processes increase the exciton temperature by an amount as high as $\sim 10$ K. These processes impose a new restriction on the possibility of exciton Bose-Einstein condensation and make impossible its achievement in a system of direct excitons in GaAs quantum wells even for resonantly excited exciton gas.