The dissimilar resistive switching properties in ZnO–Co and ZnO films

Nanostructured ZnO–Co and ZnO films with Pt, Cu, and Co as top electrodes, and Pt as bottom electrodes were grown by magnetron sputtering. Both ZnO–Co and ZnO films show bipolar resistive switching characteristics. The resistive switching properties of ZnO films are strongly dependent on the top electrode materials. The effect of top electrodes on resistive switching of ZnO–Co films is weakened due to the dominant roles of Co particles in the films. It is different with ZnO films that the ZnO–Co film shows a forming-free process. The calculation from the classical electromagnetism theory indicates that the existence of Co nanoparticles in the ZnO switching matrix can enhance the local electrical field to some extent, and decrease the operating voltages. So the device with a ZnO–Co film as a switching matrix can significantly reduce power consumption, weaken the dependence of the electrode materials, and optimize the resistive switching performance. (paper)