Thin films of tungsten oxide materials for advanced gas sensors

Abstract Thin film technology shows high promise in fabrication of electronic devices such as gas sensors. Tungsten trioxide (WO3), as one of the best-known metal oxide semiconductors (MOS) sensing materials, has attracted significant interest for application in gas sensors. In this review, WO3 thin films and their promising utilization as the sensing layers are overviewed to highlight their potential in gas sensors. First, the sensing mechanism for WO3 materials is briefly discussed. Then, several methods for WO3 film preparation are summarized. Following we discuss the specific gas sensing performances of WO3 film sensors to NO2, H2, NH3, and H2S. Strategies to improve the sensor properties such as sensitivity, response-recovery speed and selectivity are also discussed. Finally, the future perspectives and challenges of WO3 thin film sensors are addressed.