Thermal-oxidative growth of aligned W₁₈O₄₉ nanowire arrays for high performance gas sensor

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• 作者：Yuxiang Qin ; ^{qinyuxiang@tju.edu.cn" class="auth_mail" title="E-mail the corresponding author}Author Vitae ; Weiwei XieAuthor Vitae ; Yang LiuAuthor Vitae ; Zhenhua YeAuthor Vitae
• 关键词：Tungsten oxide ; Gas sensor ; Nanowire arrays ; NO2
• 刊名：Sensors & Actuators: B. Chemical
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：223
• 期：Complete
• 页码：487-495
• 全文大小：2916 K

文摘

Gas sensors based on aligned arrays of W₁₈O₄₉ nanowires were formed directly via a novel route of in situ thermal oxidation of sputtered W film on the substrate attached patterned Pt electrodes. The well-developed nanowires have diameter of 10–20 nm and show roughly aligned morphology. It is found that the duration of oxygen exposure during thermal annealing plays a crucial role to harvest a pure phase of W₁₈O₄₉ nanowire with desired length. The roughly aligned W₁₈O₄₉ nanowires show favourable microstructure for gas adsorption and rapid gas diffusion. The NO₂-sensing properties of aligned W₁₈O₄₉ nanowires sensor were evaluated at 50 °C up to 200 °C over NO₂ concentration ranging from 250 ppb to 2.5 ppm. The results indicate that the W₁₈O₄₉ nanowire arrays sensor exhibits good NO₂-sensing performances at its optimal operating temperature of 150 °C, especially perfect stability and fast response–recovery characteristics. The reliable interface performance and fast gas adsorption–desorption properties of the directly assembled vertically aligned nanowire array attribute to the superior stability and quick response/recovery. The growth mechanism of aligned W₁₈O₄₉ nanowires is proposed based on the direct SEM observations on the intermediate products, and meanwhile the sensing mechanism of the corresponding sensor is analyzed.