Resistive switching and synaptic learning performance of a TiO₂ thin film based device prepared by sol–gel and spin coating techniques

Abstract

A resistance random access memory device based on TiO2 thin films was fabricated using a sol–gel spin and coating techniques. The composition, surface morphology, and microstructure of the TiO2 films were characterized using x-ray diffraction, Raman spectroscopy, scanning electronic microscopy, and transmission electron microscopy, respectively. The fabricated Al/TiO2 film/fluorine-doped tin oxide device exhibited electroforming-free bipolar resistive switching characteristics with a stable ON/OFF ratio higher than 300. The performance of the endurance cycling was still good after 100 direct sweeping cycles. A retention time of no less than 104 s was confirmed. A switching mechanism is systematically discussed based on the test results, and space-charge-limited current was found to be responsible for the switching behavior. Multilevel memory performance was realized in the as-fabricated devices. The synaptic performance was investigated by applying consecutive positive (0–2 V) and negative (0 to −1.6 V) voltage sweeps. The fabricated devices were found to exhibit ‘learning-experience’ behavior.

Memristive Equivalent Circuit Model for Battery

“…Thin-film memristive materials based on TiO 2 add ease when integrating them into electronic circuits [35]. These memristive devices, after fabricating, consist of anatase or rutile and both are very stable polymorphs allowing the oxygen vacancies and concomitant n-type conductivity to be under control even in temperatures exceeding 300 °C [37].…”

Memristive TiO2: Synthesis, Technologies, and Applications

“…In addition, the early-stage processes such as nucleation, crystal growth, and aggregation (Teychené et al, 2020 ) may play a crucial role in the sol–gel synthesis of TiO 2 nanoparticles (Cheng et al, 2017 ). The memristive devices fabricated using the sol–gel method have various areas of application and operate at a threshold voltage ranging from ~0.5 V (Abunahla et al, 2018 ) to 1.5 V (Vilmi et al, 2016 ; Hu et al, 2020 ) or higher (Illarionov et al, 2019 ) with a resistive switching ratio R OFF / R ON of 10 1 -10 5 ( Table 1 ). Thus, the functional parameters of these devices may be variable with respect to the morphology and purity of the sol–gel product, deposition method (see section Fabrication), and annealing conditions (see section Annealing and Electric Properties).…”

“…Varying the viscosity of the slurry or solution and the rotation speed, the method may be adjusted to obtain TiO 2 thin films with thicknesses down to 35 nm (Tao et al, 2020 ). Thus, the method has been proposed for fabrication of RRAM (Hu et al, 2020 ).…”

A two-dimensional polymer memristor based on conformational changes with tunable resistive switching behaviours

“…Resistive switching memory devices or memristors are considered to be the next-generation information storage and neuromorphic computing technologies due to their simple metal/ insulator/metal sandwich structure, low fabrication cost, versatile ranges of material selection, fast read and write speed, low energy consumption, high retention performance and high switching endurance. [1][2][3][4][5][6][7][8][9] Currently, the basic device mechanisms proposed for conductance switching include conductive filaments, charge transfer (CT), conformational changes, and trapping-detrapping. [10][11][12][13] Very recently, our and other groups have reported the successful fabrication of 2DP-type memory devices based on the conductive filament mechanism and charge transfer mechanism.…”