Highly asymmetric bipolar resistive switching in solution-processed Pt/TiO2/W devices for cross-point application

Resistive switching characteristics of Pt/TiO2/W devices are investigated. TiO2 thin films are grown by a sol-gel spin-coating technique. The crystal structure and chemical bonding states of the TiO2 films are investigated by X-ray diffraction and X-ray photoelectron spectroscopy. The device exhibits reversible and reproducible bistable resistive switching with a rectifying effect. The Schottky contact at the Pt/TiO2 interface limits electron injection under reverse bias and results in a rectification ratio >60 at 2 V in a low-resistance state. The switching mechanisms in our device can be interpreted as oxygen-migration-induced redox reaction at the tungsten bottom electrode (W). The rectifying effect can reduce misreading errors in a cross-point array and provides a feasible way to achieve high memory density.