Thermal quenching and retrapping effects in the photoluminescence of ${\mathrm{In}}_{\mathit{y}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{y}}$As/GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As multiple-quantum-well structures

Multiple-quantum-well structures show thermally activated quenching of the photoluminescence. There are also small changes in photoluminescence intensity as carriers emitted from one well are retrapped in another. We present a coupled-well rate-equation theory which successfully models these changes in intensity in ${\mathrm{In}}_{\mathit{y}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{y}}$As/GaAs and ${\mathrm{In}}_{\mathit{y}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{y}}$As/GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As structures. In both structures, the dominant nonradiative carrier loss from the wells is due to thermal excitation to the barriers; retrapping in the wells can be observed and is included in the model. In contrast, in ${\mathrm{In}}_{\mathit{y}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{y}}$As/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As quantum wells, a defect-related nonradiative mechanism dominates even with an Al content in the ${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As of only 5%.