Optimisation and memristive response of sol-gel derived TiO2 thin films

Herein, we developed a series of Pt/TiO₂/Pt/Ti/SiO₂ resistive switching materials with a variation in chemical composition of TiO₂ in an attempt to evaluate the parameters affecting the memristive switching behavior and, therefore, to optimize and control it. Different chemical compositions of TiO₂ were obtained by annealing the films at 400 °C for 1 hour in diverse atmospheric conditions, such as air, vacuum and oxygen environments. The elemental composition of the produced samples was analyzed by X-ray photoelectron spectroscopy (XPS), revealing the different stoichiometric ratio of Ti/O and doping/contamination with silicon, carbon, and nitrogen depending on the annealing conditions. The preliminary I-V curves were acquired with Pt dish or wire, serving as a top electrode. The results showed a superior stability, durability and reproducibility of the resistive switch behavior observed in the samples containing oxidized silicon impurities. In addition to the electrical studies, the evolution of Pt dish top electrode was monitored by optical microscopy and scanning electron microscopy (SEM), revealing mechanical and electrochemical damage of the electrode during the electroforming step.