Effect of Ag layer on the optical and electrical properties of WO3/Ag/WO3 films by magnetron sputtering

Conductive and transparent multilayer thin films consisting of three alternating layers (such as TiO₂/Ag/TiO₂ or ZnO/Cu/ZnO) have been fabricated for applications as transparent conducting oxides. In this study, WO₃/Ag/WO₃ thin films were sputtered on the glass substrate with W and Ag targets by reactive DC and RF magnetron sputtering, respectively. The effects of Ag layer on the microstructure, optical and electrical properties of the WO₃/Ag/WO₃ thin film were examined by field emission scanning electron microscopy with energy dispersive X-ray spectroscopy, X-ray diffraction, the four-point probe technique and a spectrophotometer. It was found that the WO₃ film was amorphous and Ag film was crystal. The average transmittance of WO₃ film in the 400-700 nm range was 74.2 %. The average transmittance of WO₃/Ag/WO₃ thin films was decreased with increased Ag layer thickness to 10 nm. In addition, the transmittance of WO₃/Ag/WO₃ thin films in the 350-400 nm range was higher than WO₃ film. However, all of the WO₃/Ag/WO₃ thin films were insulation.