Selective H<sub>2sub>S sensing characteristics of CuO modified WO<sub>3sub> thin films

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• 作者：Niranjan S. Ramgir ; C.P. Goyal ; P.K. Sharma ; U.K. Goutam ; S. Bhattacharya ; N. Datta ; M. Kaur ; A.K. Debnath ; D.K. Aswal ; S.K. Gupta
• 关键词：WO3 ; CuO ; Nano p&ndash ; n junction ; Gas sensing ; H2S
• 刊名：Sensors and Actuators B: Chemical
• 出版年：2013
• 出版时间：November, 2013
• 年：2013
• 卷：188
• 期：Complete
• 页码：525-532
• 全文大小：2913 K

文摘

An H<sub>2sub>S sensor based on randomly distributed nano p-n junction between CuO and WO<sub>3sub> has been demonstrated. Modification with CuO resulted in enhanced response kinetics towards H<sub>2sub>S with high selectivity. CuO modified WO<sub>3sub> thin films corresponding to 2.25 at % of Cu exhibited a sensor response of 534 in comparison to that of pure WO<sub>3sub> thin films that exhibited a sensor response of 21 towards 10 ppm of H<sub>2sub>S at an operating temperature of 300 ¡ãC. This enhanced response kinetics has been attributed to the formation of random nano p-n junctions distributed over the surface of the sensor film and the unique interaction of CuO with H<sub>2sub>S. At elevated temperature exposure to H<sub>2sub>S resulted in the conversion of CuO to CuS, which being metallic in nature causes a drastic change in the resistance of the sensor films. Formation of nano p-n junctions is supported by the increase in the sensor resistance upon CuO modification and is further corroborated by the work function studies.