Room-Temperature Observation of Trapped Exciton-Polariton Emission in GaN/AlGaN Microcavities with Air-Gap/III-Nitride Distributed Bragg Reflectors

We demonstrate trapped exciton-polariton emission at room temperature from nonpolar GaN/AlGaN cavities sandwiched between air/AlGaN distributed Bragg reflectors. Nanoscale thickness fluctuations characteristic to the nonpolar AlGaN cavity layer create deep potential traps, giving rise to a strong (in-plane) localization of exciton-polaritons. The observed quantized exciton-polariton states exhibit a large quantized energy of up to 6 meV, which benefits from the wide bandgap of III-nitrides. The experimental results are well explained by numerical simulations. III-Nitride exciton-polaritons in such deep traps will be useful for practical exciton-polariton lasers with high degrees of coherence and high-repetition rate Josephson oscillators with multicomponent condensates.