A Selective Etching Route for Large-Scale Fabrication of β-Ga₂O₃ Micro-/Nanotube Arrays

In this paper, based on the different etching characteristics between GaN and Ga₂O₃, large-scale and vertically aligned β-Ga₂O₃ nanotube (NT) and microtube (MT) arrays were fabricated on the GaN template by a facile and feasible selective etching method. GaN micro-/nanowire arrays were prepared first by inductively coupled plasma (ICP) etching using self-organized or patterning nickel masks as the etching masks, and then the Ga₂O₃ shell layer converted from GaN was formed by thermal oxidation, resulting in GaN@Ga₂O₃ micro-/nanowire arrays. After the GaN core of GaN@Ga₂O₃ micro-/nanowire arrays was removed by ICP etching, hollow Ga₂O₃ tubes were obtained successfully. The micro-/nanotubes have uniform morphology and controllable size, and the wall thickness can also be controlled with the thermal oxidation conditions. These vertical β-Ga₂O₃ micro-/nanotube arrays could be used as new materials for novel optoelectronic devices.