Gallium oxide nanowires (NWs) were synthetized using a vapor-liquid-solid route via carbothermal reduction. These NWs were characterized using XRD, SEM and TEM as well as photoluminescence spectroscopy, confirming their crystalline nature. Gas sensors, based on individual NWs, deposited on suspended microhotplates, were tested towards several gases of interest at different temperatures. The sensing towards relative humidity provided the best results, with responses up to 20% at room temperature (~25 °C).

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Active research in nanostructured materials aims to explore new paths for improving electronic device characteristics. In the field of gas sensors, those based on metal oxide single nanowires exhibit excellent sensitivity and can operate at extremely low power consumption, making them a highly promising candidate for a novel generation of portable devices. The mix of two different metal oxides on the same nanowire can further broaden the response of this kind of gas sensor, thus widening the range of detectable gases, without compromising the properties related to the active region miniaturization. In this paper, a first study on the synthesis, characterization and gas sensing performance of (GaxIn1-x)2O3 nanowires (NWs) is reported. Carbothermal metal-assisted chemical vapor deposition was carried out with different mixtures of Ga2O3, In2O3 and graphite powders. Structural characterization of the NWs revealed that they have a crystalline structure close to that of In2O3 nanowires, with a small amount of Ga incorporation, which highly depends on the mass ratio between the two precursors. Dedicated gas nanosensors based on single NWs were fabricated and tested for both ethanol and nitrogen dioxide, demonstrating an improved performance compared to similar devices based on pure In2O3 or Ga2O3 NWs.