Excitons in strained (Ga,In)Sb/GaSb quantum wells

We examine the nature of the lowest-energy optical transition in high-quality (Ga,In)Sb/GaSb quantum wells. Despite the weak electron-hole interaction existing in this system, we observe a distinct exciton resonance in absorption. From the analysis of this resonance, we determine the binding energy and the oscillator strength of the quantum-confined exciton. The coincidence of the photoluminescence peak with the absorption resonance demonstrates that the dominant radiative channel is excitonic. Finally, we show that the thermal quenching of luminescence is related to the thermionic emission of excitons out of the well.