Of Wo <sub> 3 </ Sub> Thin Films And Characteristics Of Study

A pair of interdigitated Au-film electrodes and WO3 thin films were deposited on glass ceramics substrates by vacuum thermal evaporation and then annealed at temperature between 300℃—600 ℃. X ray diffraction (XRD) and Scan electronic microscope (SEM) were used to analysis the structure of the acquired WO3 thin films. It is shown that the crystallite phase and the mean grain size changed considerably with the change of the annealing temperature. As the annealing temperature increased, the general crystallite size considerably increased, and the WO3 thin amorphous films began to crystallize. And finally we got WO3 thin films with hexagonal structure, which grew preferentially on the direction <100>. Finally the humidity and NO2 response of WO3 sensing thin films had been measured and the influence of annealed temperature to the humidity and NO2 response of WO3 sensing thin films had been analyzed. Resistance of both samples decreases as environmental humidity increases, in accordance with the theory of WO3 thin film's humidity sensitivity. Annealing conditions and working temperatures plays an important role in its NO2 sensitivity characteristic, the optimum annealing temperature resulted to be 600℃, the optimum working temperatures resulted to be 200℃.