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

In this study, nitrogen-doped WOx thin films are investigated for the improvement of resistive switching (RS) properties. Compared to WOx thin films, nitrogen-doped WOx 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 WOx:N thin films forms WN nanoclusters and Wx (O, N) phases, which are beneficial to improve the RS properties in WOx thin films; WN nanoclusters can locally enhance the electric field to form stable conductive filament while Wx (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 in WOx thin films.