Theory of exciton–polariton in GaN thin films

In this work we study exciton–polariton modes confined in wurtzite GaN thin films on sapphire substrates. Using standard electromagnetic boundary conditions, together with the exciton additional boundary condition, the exciton–polariton dispersion relation is then obtained, in both s and p-polarization, by solving a secular determinant. Our results show that the exciton quantized energies lie outside the bulk modes, with mixed surface and guided modes.