Photocatalytic Reduction of Graphene Oxide–TiO₂ Nanocomposites for Improving Resistive‐Switching Memory Behaviors

Abstract

Graphene oxide (GO)-based resistive-switching (RS) memories offer the promise of low-temperature solution-processability and high mechanical flexibility, making them ideally suited for future flexible electronic devices. The RS of GO can be recognized as electric-field-induced connection/disconnection of nanoscale reduced graphene oxide (RGO) conducting filaments (CFs). Instead of operating an electrical FORMING process, which generally results in high randomness of RGO CFs due to current overshoot, a TiO₂ -assisted photocatalytic reduction method is used to generate RGO-domains locally through controlling the UV irradiation time and TiO₂ concentration. The elimination of the FORMING process successfully suppresses the RGO overgrowth and improved RS memory characteristics are achieved in graphene oxide-TiO₂ (Go-TiO₂ ) nanocomposites, including reduced SET voltage, improved switching variability, and increased switching speed. Furthermore, the room-temperature process of this method is compatible with flexible plastic substrates and the memory cells exhibit excellent flexibility. Experimental results evidence that the combined advantages of reducing the oxygen-migration barrier and enhancing the local-electric-field with RGO-manipulation are responsible for the improved RS behaviors. These results offer valuable insight into the role of RGO-domains in GO memory devices, and also, this mild photoreduction method can be extended to the development of carbon-based flexible electronics.