Quantum theory of luminescence in multiple-quantum-well Bragg structures

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Abstract
The quantum emission in radiatively coupled semiconductor multiple-quantum-well structures is investigated theoretically. It is shown that coupling effects can lead to a subradiant suppression of the emission compared to the emission of a single quantum well (QW). The suppression strength depends on the number and spacing of the QWs as well as on the homogeneous broadening and leads to an enhancement of the radiative lifetime of excitons in the structure. The strongest lifetime enhancement is found for Bragg-arranged QWs with small homogeneous broadening. Additionally, the radiative coupling between the QWs provides an exciton pumping mechanism such that excitons can directly be created into the state that has vanishing center-of-mass momentum.