The influence of ion implantation-induced oxygen vacancy on electrical conductivity of WO3 thin films

In this paper, WO3 thin films were implanted by Ar+ ions at 100 keV to the fluences of 1 x 10(15) and 1 x 10(16) ions/cm(2). The electrical conductivity of the implanted samples was measured. Four orders of magnitude increase in the electrical conductivity was observed in the implanted WO3 compared to the pristine WO3. The influence of thermal annealing in vacuum on the electrical conductivity of the implanted samples was also investigated. Thermal annealing further improved the electrical conductivity. X-ray diffraction (XRD), optical image and X-ray photoelectron spectroscopy (XPS) analyses revealed the formation of oxygen vacancy in the implanted sample. It is proposed that the energy levels associated to single charge state of oxygen vacancy serves as donors, improving the electrical conductivity.