Memristive Behavior in Thin Anodic Titania

A common material in creating memristors is titanium dioxide (TiO₂), grown by atomic layer deposition, sputtering, or sol-gel process. In this letter, we study the memristive behavior in thin TiO₂ films fabricated by brief electrochemical anodization of titanium. The effects of different anodization times and annealing are explored. We discover that inherent oxygen-vacancies at the bottom Ti/TiO₂ interface naturally lead to memristive switching in nonannealed films. Annealing induces extra oxygen vacancies near the top metal/oxide interface, which leads to symmetric and ohmic current-voltage characteristics with a collapse of memristive switching. No clear dependence on anodization time was observed for times between 1 s and 1 min.