Ultrasensitive WO₃ gas sensors for NO₂ detection in air and low oxygen environment

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• 作者：Barbara Urasinska-Wojcik^aAuthor Vitae ; Timothy A. Vincent^aAuthor Vitae ; Mohamed F. Chowdhury^bAuthor Vitae ; Julian W. Gardner^a ; ^b ; ^{J.W.Gardner@warwick.ac.uk" class="auth_mail" title="E-mail the corresponding author}Author Vitae
• 关键词：Gas sensor ; Lean air ; Metal oxide ; Nitrogen dioxide
• 刊名：Sensors & Actuators: B. Chemical
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：239
• 期：Complete
• 页码：1051-1059
• 全文大小：3053 K

文摘

We report here on the results of a study into the response of a tungsten oxide based low power MEMS gas sensor to ppb of nitrogen dioxide at low levels of ambient oxygen. It was found that the resistive gas sensors not only had a high sensitivity to NO₂ (3.4%/ppb vs. 0.2%/ppb obtained for commercial MOX) but can still operate reliably at lower oxygen levels (down to 0.5%) - albeit with slightly longer response and recovery times. The optimal operating temperature was determined to be ca. 350 °C and so easily within the range of a MEMS based SOI CMOS substrate. The response was sensitive to significant changes in ambient humidity, but was found to have low cross-sensitivity to CO, hydrogen, methane, and acetone even at much higher ppm levels. We believe that these tungsten oxide gas sensors could be exploited in harsh applications, i.e. with a low oxygen (lean) environment often associated in the exhaust gases from combustion systems.