Switching properties of titanium dioxide nanowire memristor

We present the memristive switching properties in a single nanowire device made of titanium dioxide. We constructed the single oxide nanowire device made of titanium dioxide on a Si substrate. First, we confirmed the existence of memristive switching in a 10 nm scale nanowire device. We successfully extracted the carrier-types for memristive switching by utilizing atmosphere control measurements. Although cobalt oxide and nickel oxide showed the p-type behavior reported previously, the present titanium dioxide nanowire memristor exhibited n-type behavior. Our results highlight the fact that carrier-type of memristive switching seems to be consistent with that of a bulk material, but this is in fact somehow contradictive to a model based on precipitation of metals within an oxide matrix. Since, in conventional capacitor-type memristors, it has been impossible to measure the carrier-type in memristive switching because memristive events are buried within a solid, the open-top planar-type "nanowire memristor" is clearly a powerful device for extracting the intrinsic features of memristive switching phenomena.