Microstructure and electric properties of Ag-SiO2 nanocomposite films

The effects of SiO2 content and deposition temperature on the microstructure and electric properties of the Ag-SiO2 nanocomposite films were investigated. A series of Ag-SiO2 nanocomposite films with different composition were deposited by magnetron sputtering Ag and SiO2 targets at different temperatures. The composition and microstructure of the films were characterized with energy dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscope, transmission electron microscope. A four-probe resistivity tester was used to measure their resistivity. The experimental results reveal that the microstructure consists of polycrystalline silver and the mixture of fine granular Ag and amorphous SiO2. With an increase of SiO2 content, Ag crystals in the films deposited at room temperature become finer and distribute as meshed and the resistivity of the films increases. With the deposition temperature rising, silver particles accumulate to form nanocrystalline granules gradually. Correspondingly, the resistivity of the films rises remarkably.