THERMAL QUENCHING OF THE PHOTOLUMINESCENCE OF INGAAS/GAAS AND INGAAS/ALGAAS STRAINED-LAYER QUANTUM-WELLS

Photoluminescence in InGaAs/GaAs strained-layer quantum wells is strongly quenched by temperatures above 10-100 K, depending on the well width. Analysis of this dependence shows that the quenching mechanism is thermal activation of electron-hole pairs from the wells into the GaAs barriers, followed by nonradiative recombination through a loss mechanism in bulk GaAs. The addition of Al to the barriers to improve confinement eliminates loss through this route but introduces another loss mechanism, characterized by an activation energy independent of well width and with a smaller pre-exponential factor.