Resistive switching multistate nonvolatile memory effects in a single cobalt oxide nanowire

A multistate nonvolatile memory operated at sublithographic scale has been strongly desired since other nonvolatile memories have confronted the fundamental size limits owing to their working principles. Resistive switching (RS) in metal?oxide?metal junctions, so-called ReRAM, is promising for next generation high-density nonvolatile memory. Self-assembled oxide nanowire-based RS offers an attractive solution not only to reduce the device size beyond the limitation of current lithographic length scales but also to extract the underlying nanoscale RS mechanisms. Here we demonstrate the multistate bipolar RS of a single Co₃O₄ nanowire (10 nm scale) with the endurance up to 10⁸. In addition, we succeeded to extract a voltage-induced nanoscale RS mechanism rather than current-induced RS. These findings would open up opportunities to explore not only for the intrinsic nanoscale RS mechanisms with the ultimate size limit but also for next generation multistate three-dimensional ReRAM.