Fabrication and characterization of β-Ga2O3 optical nanowires

Monoclinic gallium oxide (β-Ga2O3) nanowires with lengths of tens of micrometers and diameters ranging from 100 to 250 nm are synthesized using simple physical evaporation based on vapor-liquid-solid (VLS) mechanism. The as-synthesized straight β-Ga2O3 nanowires show excellent diameter uniformity and sidewall smoothness, making them suitable for optical wave-guiding. Light from a fiber taper is launched into the nanowire by means of evanescent coupling. Measured propagation loss of the nanowire at 633 nm wavelength is on the order of 10 dB/mm. Favorable mechanical strength of these nanowires for elastic bending is also observed. Our results suggest that β-Ga2O3 nanowires are promising building blocks for micro- and nanophotonic circuits and devices.