Low switching-threshold-voltage zinc oxide nanowire array resistive random access memory

We have performed the fabrication and characterization of resistive random access memory devices based on Au/ZnO nanowires/Ag capacitor structure. First, vertically aligned ZnO nanowires were grown on Ag electrode layer. The poly 4-vinyl phenol (PVP) was then spin-coated on nanowires as a support and isolation layer. After appropriate etching of PVP in oxygen plasma to expose ZnO nanowire tips, a layer of Au was sputtered onto the tips of ZnO nanowires forming the top electrode. The resulting ZnO nanowire array devices were found to exhibit bipolar resistive switching characteristics. Switching between high resistance state (HRS) and low resistance state (LRS) could be achieved at a very low threshold voltage of 0.3 V for a long conducting channel of 500 nm, exhibiting a very low electric field, without electrical forming. The resistance ratios of HRS to LRS were higher than two orders of magnitude. The results indicate the application potentials of Au/ZnO nanowires/Ag devices for nonvolatile memory devices.