Transparence and electrical properties of ZnO-based multilayer electrode

Three-layered ZnO/Ag-Ti/ZnO structures were prepared using both the sol-gel technique and DC magnetron sputtering. This study focuses on the electrical and optical properties of the ZnO/Ag-Ti/ZnO multilayers with various thicknesses of the Ag-Ti layer. The ZnO thin film prepared by the sol-gel method was dried at 300°C for 3 minutes, and a fixed thickness of 20 nm was obtained. The thickness of the Ag-Ti thin film was controlled by varying the sputtering time. The Ag-Ti layer substantially reduced the electrical resistivity of the sol-gel-sprayed ZnO thin films. The sheet resistance of the Ag-Ti layer decreased dramatically and then became steady beyond a sputtering time of 60 s. The sputtering time of Ag-Ti thin film deposition was determined to be 60 s, taking into account the optical transmittance. Consequently, the transmittance of the ZnO/Ag-Ti/ZnO multilayer films was 71% at 550 nm and 60% at 350 nm. The sheet resistance was 4.2 Ω/sq.