Study of copper-doped SiO2 films prepared by co-sputtering of copper and SiO2

Thin composite films were deposited by simultaneous dc-sputtering of copper and rf-sputtering of silicon dioxide in pure argon. Structure of the composite films was analyzed by photoelectron spectroscopy, X-ray diffraction and transmission electron microscopy. The as-deposited films were composed of Cu2O crystallites and SiOx matrix. A complicated nanostructure evolved upon annealing the films between 150 and 300 °C for 1-3 h in vacuum. The size of Cu2O crystallites inside the films increased after annealing. Meanwhile, Cu particles precipitated on the surface of the composite films and void channels were derived inside the composite films after annealing.