Room-temperature polariton luminescence from a bulk GaN microcavity

Abstract

We report strong exciton-photon coupling at room temperature in a hybrid high quality bulk $3\ensuremath{\lambda}∕2$ GaN cavity with a bottom lattice-matched $\mathrm{Al}\mathrm{In}\mathrm{N}∕\mathrm{Al}\mathrm{Ga}\mathrm{N}$ distributed Bragg reflector through angle-resolved polarized photoluminescence (PL). Coupling of the optically active free excitons (${X}_{A}$, ${X}_{B}$, and ${X}_{C}$) to the cavity mode is demonstrated, with their contribution to the PL spectra varying with polarization. Under TE polarization, exciton oscillator strengths for ${X}_{A}$ and ${X}_{B}$ are about one order of magnitude larger than in bulk GaAs. Photoluminescence exhibits a strong bottleneck effect despite its thermal lineshape.