Abstract
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.
Highlights
In the last four decades, gas sensors have undergone extraordinary development, driven by their paramount role in indoor/outdoor environmental and automotive/industrial air monitoring
We aimed to evaluate any possible effect on the synthesis caused by the progressive accumulation of by-products deposited on the sidewalls of the chamber, and to estimate the Ga content in the samples under these extreme conditions, even if in an uncontrolled manner
The growth of (Gax In1-x )2 O3 NWs was carried out using the carbothermal metal-assisted VLS mechanism. This was achieved for different proportions of Ga2 O3 –In2 O3 precursors to explore different Ga concentrations
Summary
In the last four decades, gas sensors have undergone extraordinary development, driven by their paramount role in indoor/outdoor environmental and automotive/industrial air monitoring. Among the different classes of available devices, those relying on semiconducting metal oxides (MOx) as the sensing material are popular [1], due to their low cost, robustness and high sensitivity. Their sensing principle is based on the variation of the electrical resistance when in the presence of certain gases [2,3,4]. The driver of this sizeable change is the interaction of the O-atoms at the semiconductor’s surface with the adsorbed gas molecules. In general, this class of devices presents some drawbacks, such as poor selectivity towards a gas mixture and the requirement of a high operating temperature, with the consequent large power consumption
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