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24 April 2003 Layered SAW nitrogen dioxide sensor with WO3 selective layer
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Proceedings Volume 5116, Smart Sensors, Actuators, and MEMS; (2003)
Event: Microtechnologies for the New Millennium 2003, 2003, Maspalomas, Gran Canaria, Canary Islands, Spain
A multi-layered surface acoustic wave (SAW) transducer employing an R.F. magnetron sputtered tungsten trioxide (WO3) thin film as a selective layer, for low concentration nitrogen dioxide (NO2) gas sensing is presented. The layered SAW device structure is fabricated on a 36° Y-cut, X-propagating LiTaO3 substrate with a zinc oxide (ZnO) guiding layer. The dominant mode of acoustic propagation in the sensor is a combination of mainly a shear and a longitudinal displacement types. Such a structure has the advantage of confining the acoustic wave energy to the surface of the device, which increases the sensitivity of the system. A frequency shift of 30 kHz is shown for a concentration of 500ppb of NO2 in synthetic air, highlighting the possibility of such a sensor being targeted towards the sub-ppb levels of NO2.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Samuel James Ippolito, Kourosh Kalantar-zadeh, Adrian Trinchi, David A. Powell, and Wojtek Wlodarski "Layered SAW nitrogen dioxide sensor with WO3 selective layer", Proc. SPIE 5116, Smart Sensors, Actuators, and MEMS, (24 April 2003);

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