The preparation of ZnO/Ag nanocomposites and study on electrical properties

At room temperature, ZnO nanopartikel-suspension was prepared by ultrasonic method in the dispersed system of water and hexane (19:1) with Zn which was processed by mechanical milling for 13 h. Then, AgNO3 was photoredued to prepare ZnO/Ag nanocomposites. The XRD and TEM were use to analyze ZnO/Ag composite particles. The SEM and I-V tester were use to test ZnO/Ag composite thin films and electrical properties. The results of XRD and TEM showed that ZnO synthesized by ultrasonic method was short rod-like with the wurzite hexagonal structure and length of about 20 nm; the structure of Ag nano-particles on the surface of ZnO by photo-reduction method was face-centered cubic. The SEM and I-V results revealed that drying temperature had a great influence on the composite structure. When drying temperature was 60°C, the composite thin film had compact and uniform structure and break-over voltage was about 2 V; when drying temperature was 100°C, the structure of the composite thin film was transformed into the Ag network of composites with ZnO branches and break-over voltage was about 0.02 V. By controlling the drying temperature, combinations of ZnO with Ag in composite thin films and the electrical properties could be changed.