Resistive switching characteristics and mechanism of W/TiO2/ITO devices

Abstract

In recent years, titanium oxide (TiO2)-based memristors have come under widespread investigation due to their compatibility with CMOS technology and their potential use as the forthcoming nonvolatile memories. However, the practical application of these devices requires a detailed understanding of their switching mechanism. This study examined the resistive switching and conduction mechanism of titania films on an Indium tin oxide (ITO) substrate with tungsten (W) serving as the top electrode (TE). The thin film of TiO2 was fabricated by solution processing and spin coating technique. The sol was prepared using titanium tetra isopropoxide (TTIP) and ethanol. Optical characterization was done using UV–Visible transmission spectroscopy. From the tauc plot, the band gap of films treated at 250 °C and 400 °C was found to be 3.37 eV and 3.29 eV, respectively. From the electrical analysis, a pinched hysteresis current–voltage curve was obtained, and the device exhibits stable, reversible, forming-free, and interface type resistance-switching characteristics.The homogeneous switching observed in this device is caused by oxygen vacancy-induced barrier modulation at the metal-oxide interface. The I-V data were fitted to various conduction mechanismsand it was found that ohmic conduction and Schottky emission mechanism (SE) were dominant in the low and high field regions, respectively, for both HRS and LRS.