Temperature-dependent exciton behavior in quaternary GaInAsSb/AlGaAsSb strained single quantum wells

Abstract
We report the temperature‐dependent exciton behavior in a quaternary Ga0.67In0.33As0.01Sb0.99/Al0.25Ga0.75As 0.2Sb0.98 strained single‐quantum‐well (SQW) structure by photoluminescence spectroscopy. Strong exciton resonances are observed and have been attributed to localized excitons below 80 K and to free excitons at high temperatures. Nevertheless, we show that the experimental results of stronger exciton–phonon coupling in the quaternary SQW structure would lead to partial ionization of free excitons at temperatures above 125 K, in good agreement with the line‐shape analysis of the luminescence spectra which clearly shows the presence of band‐to‐band recombination.