| Summary: | <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> nanostructures are attractive wide-band-gap semiconductor materials as they exhibit promising photoelectric properties and potential applications. Despite the extensive efforts on <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> nanowires, investigations into <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> nanotubes are rare since the tubular structures are hard to synthesize. In this paper, we report a facile method for fabricating <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> nanotubes using pre-synthesized GaSb nanowires as sacrificial templates. Through a two-step heating-treatment strategy, the GaSb nanowires are partially oxidized to form <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> shells, and then, the residual inner parts are removed subsequently in vacuum conditions, yielding delicate hollow <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> nanotubes. The length, diameter, and thickness of the nanotubes can be customized by using different GaSb nanowires and heating parameters. In situ transmission electron microscopic heating experiments are performed to reveal the transformation dynamics of the <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> nanotubes, while the Kirkendall effect and the sublimation process are found to be critical. Moreover, photoelectric tests are carried out on the obtained <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> nanotubes. A photoresponsivity of ~25.9 A/W and a detectivity of ~5.6 × 10<sup>11</sup> Jones have been achieved with a single-<i>β</i>-Ga<sub>2</sub>O<sub>3</sub>-nanotube device under an excitation wavelength of 254 nm.
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