Effects of Preparing Conditions on NO_(2-)sensing Properties of Sputtered WO_3 Nano-films

摘要

WO_3 nano-films were deposited on A1_2O_3 substrate by dc reactive magnetron sputtering method. The effects of preparing conditions, such as the discharge gas ratio (Ar:O_2), working pressure, sputtering time and annealing temperature on microstructure, crystalline state and NO_2-sensing properties of WO_3 nano-films were investigated by orthogonal trial experiment method. The optimum technological conditions were determined by orthogonal test and extreme difference analysis. The crystallization, morphology and composition of WO_3 thin film obtained at the optimal parameters were studied by XRD, SEM and XPS. The gas sensing mechanism was also studied. WO_3 nano-film shows high sensitivity, fast response, good selectivity at the best operating temperature 200°C.