LOW-TEMPERATURE ANTI-STOKES LUMINESCENCE MEDIATED BY DISORDER IN SEMICONDUCTOR QUANTUM-WELL STRUCTURES

In low-temperature photoluminescence experiments on II-VI semiconductor quantum wells we find an energy transfer from confined quantum-well states to above-barrier states. The observed anti-Stokes barrier luminescence exhibits a characteristic intensity dependence showing that this transfer is caused by a two-step absorption process involving localized or impurity bound-exciton states in the quantum well. Time-resolved photoluminescence experiments show that the photon for the second intraband absorption step can be provided by the quantum-well luminescence, i.e., the anti-Stokes barrier luminescence is a direct consequence of photon recycling. © 1995 The American Physical Society.