Influence of magnetron sputtering process on the stability of WO3 thin film gas sensor

Thick-film WO3 sensors prepared by traditional preparation processes such as screen printing have poor repeatability and stability, limiting the practical application of WO3. In this paper, WO3 nano-thin films were prepared on electrode sheets by magnetron sputtering, which significantly improved the stability of WO3 gas sensors. Through morphology characterization and gas sensing test, the optimal sputtering process parameters were determined as sputtering time 10 min, sputtering oxygen flow rate 30 sccm, sputtering power 30 W, sputtering pressure 3.4 Pa, and deposition temperature 25 ℃. Under this sputtering condition, a uniform and dense WO3 thin film was acquired, which exhibited excellent gas sensitivity, repeatability and stability to H2S at 250 ℃. Specifically, the response value to 10 ppm H2S is 40.1, the fluctuation deviation of the response value is only 1.0 % and the baseline drift rate is 2.0 %, showing good short-term stability. In addition, during the two-month test, the response value dropped by only 3.1 %, indicating that the sensor has good long-term stability.