Fabrication of β-Ga₂O₃ Nanotubes via Sacrificial GaSb-Nanowire Templates

β-Ga₂O₃ nanostructures are attractive wide-band-gap semiconductor materials as they exhibit promising photoelectric properties and potential applications. Despite the extensive efforts on β-Ga₂O₃ nanowires, investigations into β-Ga₂O₃ nanotubes are rare since the tubular structures are hard to synthesize. In this paper, we report a facile method for fabricating β-Ga₂O₃ nanotubes using pre-synthesized GaSb nanowires as sacrificial templates. Through a two-step heating-treatment strategy, the GaSb nanowires are partially oxidized to form β-Ga₂O₃ shells, and then, the residual inner parts are removed subsequently in vacuum conditions, yielding delicate hollow β-Ga₂O₃ 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 β-Ga₂O₃ nanotubes, while the Kirkendall effect and the sublimation process are found to be critical. Moreover, photoelectric tests are carried out on the obtained β-Ga₂O₃ nanotubes. A photoresponsivity of ~25.9 A/W and a detectivity of ~5.6 × 10¹¹ Jones have been achieved with a single-β-Ga₂O₃-nanotube device under an excitation wavelength of 254 nm.