Memristive Behavior of ZnO/Au Film Investigated by a TiN CAFM Tip and Its Model Based on the Experiments

Memristive behavior is found in nanoscale contact between conductive atomic force tip and ZnO/Au device, which is fabricated by molecular beam epitaxy. Stable resistive switching behaviors can be repeated for hundreds of times. The resistance ratio of high-resistance state to low-resistance state can be up to 100 times. The memristive behaviors could persist for months, but the switching voltage for several special points could change with time resulting from the metal atoms permeating or the decreasing of oxygen vacancies. The memristive characteristics could be explained by the changing of interface barrier between the conductive atomic force tip and the ZnO film. Especially, an idealized model is formulated based on the device structure to study the memristive characteristics, and the calculated result is consistent with the present experiment.