(In,Ga)N-GaN resonant Bragg structures with single and double quantum wells in the unit supercell

We study the formation of a superradiant optical mode in the room temperature reflection spectra from resonant Bragg structures (RBSs) composed of single and double (In,Ga)N quantum wells (QWs) in the unit cell. The appearance of the mode manifests itself by a significant increase in the resonant optical reflectivity due to the electromagnetic coupling of quasi-two-dimensional excitons in the QWs. The implementation of the supercells with double (In,Ga)N QWs results in an increase in the oscillator strength of the quasi-2D excitons and corresponding rise of the radiative broadening parameter to the value as high as 0.3 ± 0.02 meV. We also show that the supercells with double QWs are preferable for RBS with large number of periods due to better tolerance to deviations from the exact periodicity.