Colossal resistive switching behavior and its physical mechanism of Pt/p-NiO/n-Mg0.6Zn0.4O/Pt thin films

Abstract

A heterojunction structure of p-NiO/n-Mg0.6Zn0.4O with an aim to tuning or improving the resistive switching properties was fabricated on Pt/TiO2/SiO2/Si substrates by the sol-gel spin-coating technique. The Pt/NiO/Mg0.6Zn0.4O/Pt heterojunction thin-film device shows excellent resistive switching properties, such as a reduced threshold current of 1 μA for device initiation, a small dispersion of reset voltage ranging from 0.54 to 0.62 V, long retention time and a high resistance ratio of high-resistance state to low-resistance state about six orders of magnitude. These results indicate that the resistive switching properties can be greatly improved by constructing the p-NiO/n-Mg0.6Zn0.4O heterojunction for nonvolatile memory applications. The physical mechanism responsible for colossal resistive switching properties of the heterojunction was analyzed based on interfacial defect effect and formation and rapture of conductive filaments.