Improved resistive switching properties by nitrogen doping in tungsten oxide thin films

In this study, nitrogen-doped WO_x thin films are investigated for the improvement of resistive switching (RS) properties. Compared to WO_x thin films, nitrogen-doped WO_x thin films exhibit a higher on/off current ratio (a separation of ∼2 orders of magnitude), better endurance (>100 cycles), narrower current dispersion, and longer retention characteristics (>10⁴ s). Electrical measurements, X-ray diffraction, and X-ray photoelectron spectroscopy demonstrate that nitrogen in WO_x:N thin films forms WN nanoclusters and W_x (O, N) phases, which are beneficial to improve the RS properties inWO_x thin films; WN nanoclusters can locally enhance the electric field to form stable conductive filament while W_x (O, N) phases can suppress random migrations of oxygen ions (O2-), leading to stable RS characteristics. Our findings suggest that nitrogen doping method can lead further optimization of the RS characteristics inWO_x thin films.