Ammonia Sensing Characteristics of a Tungsten Trioxide Thin-Film-Based Sensor

Abstract

A tungsten trioxide (WO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) thin-film-based ammonia sensor device prepared using radio frequency sputtering is reported and studied. A very thin WO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> film (~10 nm) is employed in the studied device. Experimentally, the studied device exhibits a high ammonia sensing response of 13.7 (at 1000-ppm NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /air, 250 °C), an extremely low detection level (≤10-ppb NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /air, 250 °C), a relatively low optimal operating temperature of 250 °C, and a widespread sensing concentration range. Furthermore, the device shows advantages including a simple structure, easy fabrication, and relatively lower operating temperature (≤250 °C). Thus, the proposed WO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> thin-film-based sensor device is promising for high-performance ammonia sensing applications.