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A MEMS-based Benzene Gas Sensor with a Self-heating WO3 Sensing Layer
Department of Energy and Refrigerating Air-conditioning Engineering, National Taipei University of Technology, Taiwan, Taiwan 106
Department of Materials Engineering, National Pingtung University of Science and Technology, Pingtung, Taiwan 912
* Authors to whom correspondence should be addressed.
Received: 31 March 2009; in revised form: 17 April 2009 / Accepted: 21 April 2009 / Published: 21 April 2009
Abstract: In the study, a MEMS-based benzene gas sensor is presented, consisting of a quartz substrate, a thin-film WO3 sensing layer, an integrated Pt micro-heater, and Pt interdigitated electrodes (IDEs). When benzene is present in the atmosphere, oxidation occurs on the heated WO3 sensing layer. This causes a change in the electrical conductivity of the WO3 film, and hence changes the resistance between the IDEs. The benzene concentration is then computed from the change in the measured resistance. A specific orientation of the WO3 layer is obtained by optimizing the sputtering process parameters. It is found that the sensitivity of the gas sensor is optimized at a working temperature of 300 °C. At the optimal working temperature, the experimental results show that the sensor has a high degree of sensitivity (1.0 KΩ ppm-1), a low detection limit (0.2 ppm) and a rapid response time (35 s).
Keywords: benzene; gas sensor; MEMS; micro-heater; WO3 thin film
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MDPI and ACS Style
Ke, M.-T.; Lee, M.-T.; Lee, C.-Y.; Fu, L.-M. A MEMS-based Benzene Gas Sensor with a Self-heating WO3 Sensing Layer. Sensors 2009, 9, 2895-2906.
Ke M-T, Lee M-T, Lee C-Y, Fu L-M. A MEMS-based Benzene Gas Sensor with a Self-heating WO3 Sensing Layer. Sensors. 2009; 9(4):2895-2906.
Ke, Ming-Tsun; Lee, Mu-Tsun; Lee, Chia-Yen; Fu, Lung-Ming. 2009. "A MEMS-based Benzene Gas Sensor with a Self-heating WO3 Sensing Layer." Sensors 9, no. 4: 2895-2906.