A MEMS-based Benzene Gas Sensor with a Self-heating WO3 Sensing Layer

Sensors

Ming-Tsun Ke¹  Mu-Tsun Lee¹  Chia-Yen Lee² 

[1] Department of Energy and Refrigerating Air-conditioning Engineering, National Taipei University of Technology, Taiwan, Taiwan 106; E-Mails:;Department of Materials Engineering, National Pingtung University of Science and Technology, Pingtung, Taiwan 912

关键词: benzene;    gas sensor;    MEMS;    micro-heater;    WO₃ thin film;   

DOI  :  10.3390/s90402895

来源: mdpi

【 摘 要 】

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).

【 授权许可】

CC BY   
© 2009 by the authors; licensee MDPI, Basel, Switzerland