Fabrication and characterization of TiOx based single-cell memristive devices

Abstract

Nowadays, remarkable progress has been observed in research into neuromorphic computing systems inspired by the human brain. A memristive device can behaviorally imitate the biological neuronal synapse therefore memristor-based neuromorphic computing systems have been proposed in recent studies. In this study, the memristive behaviors of titanium dioxide sandwiched between two platinum electrodes were investigated. For this purpose, three SiO _2 /Pt/TiO _x /Pt thin films with 7.2 nm, 40 nm, and 80 nm TiO _x metal-oxide layers were fabricated using a pulsed laser deposition technique. The fabrication process, structural properties, photoluminescence properties and electrical transport characterization of each thin film have been investigated. All thin films were analyzed in terms of the film stoichiometry and degree of oxidation using high-resolution x-ray photoelectron spectroscopy. By measuring the layer thickness, density, and surface roughness with the x-ray reflectivity technique, by analyzing the structural defects with photoluminescence spectroscopy and by characterizing the quasi-static electrical properties with the conventional two probes technique, we have shown that the fabricated memristive devices have bipolar digital switching properties with high R _OFF /R _ON ratio. This type of switching behavior is applicable in random access memories. Experimental current–voltage behavior in the form of pinched hysteresis loop of the films have been modelled with generalized memristor model.

Keywords

• memristor
• resistive switching
• generalized memristor model
• TiO2
• PLD
• XPS