Chlorine Gas Sensing Performance of On-Chip Grown ZnO, WO3, and SnO2 Nanowire Sensors

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• 作者：Tran Van Dang ; Nguyen Duc Hoa ; Nguyen Van Duy ; Nguyen Van Hieu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：February 24, 2016
• 年：2016
• 卷：8
• 期：7
• 页码：4828-4837
• 全文大小：624K
• ISSN：1944-8252

文摘

Monitoring toxic chlorine (Cl₂) at the parts-per-billion (ppb) level is crucial for safe usage of this gas. Herein, ZnO, WO₃, and SnO₂ nanowire sensors were fabricated using an on-chip growth technique with chemical vapor deposition. The Cl₂ gas-sensing characteristics of the fabricated sensors were systematically investigated. Results demonstrated that SnO₂ nanowires exhibited higher sensitivity to Cl₂ gas than ZnO and WO₃ nanowires. The response (R_Cl2/R_air) of the SnO₂ nanowire sensor to 50 ppb Cl₂ at 50 °C was about 57. Hence, SnO₂ nanowires can be an excellent sensing material for detecting Cl₂ gas at the ppb level under low temperatures. Abnormal sensing characteristics were observed in the WO₃ and SnO₂ nanowire sensors at certain temperatures; in particular, the response level of these sensors to 5 ppm of Cl₂ was lower than that to 2.5 ppm of Cl₂. The sensing mechanism of the SnO₂ nanowire sensor was also elucidated by determining Cl₂ responses under N₂ and dry air as carrier gases. We proved that the Cl₂ molecule was first directly adsorbed on the metal oxide surface and was then substituted for pre-adsorbed oxygen, followed by lattice oxygen.