Near-UV optical cavities in Ga₂O₃ nanowires

In this Letter, we report optical confinement in the near-ultraviolet (near-UV) range in Ga₂O₃ nanowires (NWs) by distributed Bragg reflector (DBR) nanopatterned cavities. High-contrast DBRs, which act as the end mirrors of the cavities of the desired length, are designed and fabricated by focused ion beam etching. The resonant modes of the cavities are analyzed by micro-photoluminescence measurements, analytical models, and simulations, which show very good agreement between each other. Experimental reflectivities up to 50% are obtained over the 350-410 nm region for the resonances in this wavelength range. Therefore, Ga₂O₃ NW optical cavities are shown as good candidates for single-material-based near-UV light emitters.