Core-shell copper nanowire-TiO2 nanotube arrays with excellent bipolar resistive switching properties

Electrochemical nanomaterial-based resistive switching devices (memristors) have recently attracted significant research interest because of their low cost and potential applications in nonvolatile data storage and artificial neural networks . In this paper, we report an electrochemical method to produce a novel memristor based on copper nanowire-titanium dioxide nanotube arrays (TNTAs), a core-shell composite material. TNTAs are fabricated using a cheap and effective electrochemical anodization method, and high-density copper nanowires are synthesized via excess-electrodeposition with a novel peeling-off strategy. This novel memristor shows both analogue and digital resistive switching properties by controlling the electroforming process. The R off /R on ratio of the digital memristor remains greater than 40 during 1000 consecutive I–V sweeps. The device shows good endurance over 10 4 pulse cycles, with an R off /R on ratio greater than 20. Furthermore, the data retention time can be maintained at least for 10 4  s. The outstanding digital resistive switching performance can be attributed to the numerous parallel copper nanowire nanoelectrodes inside the film.