Tungsten oxide thin films for highly sensitive triethylamine detection

Metal oxide semiconductor (MOS) thin films are promising sensing layer for integration in gas sensor devices for detecting toxic and harmful molecules. Herein, tungsten oxide (WO₃) thin films are deposited on interdigital electrodes by vacuum thermal evaporation to realize batch fabrication of high-performance gas sensors. Subsequent annealing at different temperatures allows for regulation of the concentration of oxygen vacancies in the WO₃ films, which has been found to exert a great influence on the sensor properties. In addition, the surface structure of WO₃ films is also highly dependent on the annealing temperature. Gas sensing investigations show that the WO₃ sensor annealed at 500 °C possesses the best sensing properties for detecting triethylamine (TEA) including very high response, good selectivity, fast response, and low limit of detection (63 ppb). The excellent sensor performances are attributed to the enhanced adsorption of oxidative oxygen species due to the presence of abundant oxygen vacancies. The scalable fabrication of WO₃ thin film gas sensors and the oxygen vacancy engineering strategy proposed herein may shed some light to developing high performance environmental sensors.