Cavity polaritons in ZnO-based hybrid microcavities

Among wide-bandgap semiconductors, ZnO is a very attractive candidate for blue-ultraviolet lasers operating at room temperature owing to its large exciton binding energy and oscillator strength. Especially, ZnO-based microcavity structures are most conducive for polariton lasing at room temperature. We report the observation of cavity polaritons in bulk ZnO-based hybrid microcavities at room temperature. The bulk ZnO-based hybrid microcavities are composed of 29 pairs of Al0.5Ga0.5N/GaN distributed Bragg reflector (DBR) at the bottom of the lambda-thick cavity layer and eight pairs of SiO2/Si3N4 DBR as the top mirror, which provided cavity Q values of similar to 100. Anticrossing behavior between the lower and upper polariton branches was observed at room temperature. From the polariton dispersion curve, the vacuum Rabi splitting was estimated to be similar to 50 meV. These results are promising toward the realization of ZnO-based microcavity polariton devices.