Decay rate and renormalized frequency shift of superradiant excitons: Crossover from two-dimensional to three-dimensional crystals

The superradiant decay rate and renormalized frequency shift of Wannier excitons in a semiconductor film of N layers are studied. It is found that both the decay rate and renormalized frequency shift show oscillatory dependence on layer thickness. The crossover from the superradiant exciton to the bulk polariton when varying N from 1 to (Formula presented) is also examined.