Resistive Switching Properties Research Articles

A solution-processable benzothiazole-substituted formazanate zinc(II) complex designed for a robust resistive memory device.

A novel mononuclear bis(formazanate)zinc complex (1) based on a redox-active 1-(benzothiazol-2-yl)-5-(2-benzoyl-4-chlorophenyl)-3-phenyl formazan ligand has been synthesized and characterized. Complex 1 was prepared by reacting one equivalent of Zn(OCOCH3)·2H2O with two equivalents of the corresponding formazan derivative. X-ray crystallography was employed to ascertain the solid-state structure of compound 1, and the analysis revealed a distorted octahedral geometry for the complex where the symmetrical ligands exhibit a preference for coordinating with the zinc center in the 'open' form, generating five-membered chelate rings. Moreover, cyclic voltammetry analysis reveals that complex 1 exhibits the capacity for electrochemical reduction as well as oxidation, resulting in the formation of radical anionic (L2Zn-) and dianionic (L2Zn2-) states as well as the oxidation state of 1. Additionally, the developed solution-processable complex 1 was employed as the fundamental building material for resistive switching memory applications. The [FTO/ZnIIL2(1)]/Ag RRAM device demonstrates exceptional resistive memory switching properties, with a substantial ION/IOFF ratio (103), low operational VSET and VRESET (0.9 V and -0.75 V) voltages, excellent endurance stability (100 cycles), and decent retention time (more than 2000 seconds). The findings presented in this study underscore the importance of redox-active formazanate metal complexes for creating promising memory storage devices.

Resistive switching properties of hafnium oxide thin-films sputtered at different oxygen partial pressures

Resistive switching properties of hafnium oxide thin-films sputtered at different oxygen partial pressures

Resistive Switching Properties in Memristors for Optoelectronic Synaptic Memristors: Deposition Techniques, Key Performance Parameters, and Applications

Resistive Switching Properties in Memristors for Optoelectronic Synaptic Memristors: Deposition Techniques, Key Performance Parameters, and Applications

Au Nanocrystals Modulate Resistive Switching and Magnetic Properties of Spinel Cobalt Oxide-Based Memory Devices

Au Nanocrystals Modulate Resistive Switching and Magnetic Properties of Spinel Cobalt Oxide-Based Memory Devices

Two-dimensional α -In2Se3 memory devices from resistive switching to synaptic plasticity

We employ two-dimensional (2D) α-In2Se3 nanosheets and polymethyl methacrylate (PMMA) materials to develop three types of devices with different resistive switching (RS) layer structures and deeply study the electrical properties and physical mechanisms of these devices. It is confirmed that the pure 2D α-In2Se3 nanosheet-based RS device is a mode of ferroelectric regulation of the potential barrier, exhibiting memristor characteristics that can mimic the synaptic plasticity. Meanwhile, PMMA can improve the RS properties of the α-In2Se3 nanosheet-based device, including the appropriate switching ratio, narrow ratio distribution, and good endurance and retention capability, but the device's physical mechanism changes to charge trapping assisted hopping mechanism from the ferroelectric regulation of the potential barrier.

Interface engineering in ZnO/CdO hybrid nanocomposites to enhanced resistive switching memory for neuromorphic computing

Resistive random-access memory (RRAMs) has attracted significant interest for their potential applications in embedded storage and neuromorphic computing. Materials based on metal chalcogenides have emerged as promising candidates for the fulfilment of these requirements. Due to its ability to manipulate electronic states and control trap states through controlled compositional dynamics, metal chalcogenide RRAM has excellent non-volatile resistive memory properties. In the present we have synthesized ZnO-CdO hybrid nanocomposite by using hydrothermal method as an active layer. The Ag/C15ZO/Pt hybrid nanocomposite structure memristors showed electrical properties similar to biological synapses. The device exhibited remarkably stable resistive switching properties that have a low SET/RESET (0.41/−0.2) voltage, a high RON/OFF ratio of approximately 105, a high retention stability, excellent endurance reliability up to 104 cycles and multilevel device storage performance by controlling the compliance current. Furthermore, they exhibited an impressive performance in terms of emulating biological synaptic functions, which include long-term potentiation (LTP), long-term depression (LTD), and paired-pulse facilitation (PPF), via the continuous modulation of conductance. The hybrid nanocomposite memristors notably achieved an impressive recognition accuracy of up to 92.6 % for handwritten digit recognition under artificial neural network (ANN). This study shows that hybrid-nanocomposite memristor performance could lead to efficient future neuromorphic architectures.

Solution-Processed Robust Multifunctional Memristor of 2D Layered Material Thin Film.

Memristors have gained significant attention recently due to their unique ability to exhibit functionalities for brain-inspired neuromorphic computing. Here, we demonstrate a high-performance multifunctional memristor using a thin film of liquid-phase exfoliated (LPE) 2D MoS2 pinched between two electrodes. Nanoscale inspection of a solution-processed MoS2 thin film using scanning electron and scanning probe microscopies revealed the high-quality and defect-free nature. Systematic current-voltage (I-V) characterizations depict a facile, nonvolatile resistive switching behavior of our 2D MoS2 thin film device with a current On/Off ratio of 103 and energy cost of only a few picojoules. Excellent performance metrics, including at least 103 cycle endurance, 104 s retention, and switching speed down to a few nanoseconds, reflect robust high-performance data storage capability. Charge carriers trapping and detrapping at the sulfur vacancy defect sites in MoS2 nanosheets mainly display the resistive switching property, supported by the impedance analysis and theoretical fitting results. Multifunctionality is leveraged through implementing two-input logic gate operations, edge computation, and crucial adaptive learning via a Pavlov's dogs experiment. Overall, our solution-processed MoS2 memristor has the potential for tremendous future opportunities in integrated circuits and different computing paradigms, including energy-efficient neuromorphic computing hardware in artificial intelligence.

Preparation of ZnO resistive switching film and its corrosion behavior in 3.5 wt.% NaCl solution

ZnO resistive switching films were prepared on the surface of SS304 using hydrothermal method combined with heat treatment. The surface and cross-sectional morphology, composition, oxygen vacancy content and semiconductor type of ZnO films were characterized. The corrosion resistance and resistance switching properties of ZnO films were determined by electrochemical methods. The oxygen vacancy formation energy, surface adsorption energy and diffusion barrier of ZnO system were calculated using first-principles. The results show that the samples with 0.5 mol/L Zn2+ and 4 mol/L NaOH have the best performance, and its corrosion resistance efficiency can reach more than 99.5 %. Calculations show that the ZnO film containing oxygen vacancies still prevents the entry of Cl−, and applied electric field promotes the formation of oxygen vacancies and conductive filaments. Thus, polarization-immersion treatment can adjust the oxygen vacancy content in film, which enables film to switch between high and low resistance states, realizing the cyclic resistance-switching performance of film and greatly extending service life.

Effect of oxygen vacancies injection on the resistance switching properties of Hf0.5Zr0.5O2

Effect of oxygen vacancies injection on the resistance switching properties of Hf0.5Zr0.5O2

Resistive Switching Properties in Copper Oxide–Graphene Oxide Nanocomposite-Based Devices for Flexible Electronic Applications

Resistive Switching Properties in Copper Oxide–Graphene Oxide Nanocomposite-Based Devices for Flexible Electronic Applications

Resistive switching modulation by incorporating thermally enhanced layer in HfO2-based memristor.

Oxide-based memristors by incorporating thermally enhanced layer (TEL) have showed great potential in electronic devices for high-efficient and high-density neuromorphic computing owing to the improvement of multilevel resistive switching. However, research on the mechanism of resistive switching regulation is still lacking. In this work, based on the method of finite element numerical simulation analysis, a bilayer oxide-based memristor Pt/HfO2 (5 nm)/Ta2O5 (5 nm)/Pt with the Ta2O5 TEL was proposed. The oxygen vacancy concentrates distribution shows that the fracture of conductive filaments (CF) is at the interface where the local temperature is the highest during the reset process. The multilevel resistive switching properties were also obtained by applying different stop voltages. The fracture gap of CF can be enlarged with the increase of the stopping voltage, which is attributed to the heat-gathering ability of the TEL. Moreover, it was found that the fracture position of oxygen CF is dependent on the thickness of TEL, which exhibits a modulation of device RS performance. These results provide a theoretical guidance on the suitability of memristor devices for use in high-density memory and brain-actuated computer systems.

Resistive switching behaviour of nickel nanoparticle-embedded naphthalene sulphonic acid-doped polyaniline nanocomposites

Hybrid nanocomposite (NC) materials comprising organic polymers and inorganic metal nanoparticles (NPs) with unique properties are popular for their advanced technological applications including resistive switching memory devices. Herein, NCs of 2-naphthalene sulphonic acid-doped polyaniline nanotubes (PANI-NSA NTs) and nickel nanoparticles (Ni NPs) were synthesized via a facile chemical synthesis procedure where metallic Ni NPs were embedded in/deposited onto the surface of PANI-NSA NTs by a simple reduction method. Different characterization methods revealed successful deposition of weak ferromagnetic Ni NPs onto the PANI-NSA matrix. The bipolar resistive switching behaviour of the as-synthesized PANI-NSA + Ni NCs was investigated under the application of voltage stress in a two-terminal sandwiched device configuration. The fabricated indium tin oxide/PANI-NSA + Ni/silver (ITO/PANI-NSA + Ni/Ag) device displays bipolar resistive switching properties having a memory window of ∼1.5 × 103, and switches effectively over 200 cycles. Ohmic conduction in the lower-voltage regime and the space-charge-limited Mott–Gurney current conduction model in the higher-voltage region were identified as major charge conduction mechanisms in the high resistive state of the device. On the other hand, in the entire low resistive state region the experimental data followed the Mott–Gurney conduction model.

Improved oxygen ion migration efficiency and resistive switching properties in SrFeOx memristor with vertical superlattice-like structure

The resistive switching (RS) behaviour between high and low resistance states in SrFeOx memristors originates from topological phase transition (TPT) induced by the migration of oxygen ions. Accelerating the migration of oxygen ions in the anisotropic crystal structure of SrFeO2.5 is of great importance for improving the RS properties and promoting the application for this TPT memristor. In this study, SrFeOx TPT memristors with different superlattice-like (SLL) structures were fabricated and the prepared devices with a vertical-type SIL structure display an ultra-low operation voltage of only 0.6 V, excellent cycling stability, data retention, and endurance performance. Moreover, the microstructures of vertical and horizontal SLL SrFeO2.5 were characterized with X-ray diffraction and transmission electron microscope. Furthermore, the differences in oxygen ion migration rate in the two structures were also tested by in-situ X-ray photoelectron spectroscopy. Finally, the optical band gaps and oxygen ion migration barriers of the two structures were calculated using first principles. All the characterizations and simulation results prove that the vertical type SrFeOx shows a higher oxygen ion migration efficiency. More encouragingly, the vertical SLL devices exhibit up to 96 % recognition accuracy for the Mixed National Institute of Standards and Technology image recognition task.

On the Application Potential of Chemically Tailored Metal Oxide and Higher Chalcogenide Nanoparticles for Nanoscale Resistive Switching Devices

Resistive switching (RS) for nonvolatile data storage is a highly relevant field of research. Up to now, RS devices are fabricated via semiconductor processing technologies. This poses the question of whether integration of chemically tailored nanoparticles, either consisting of valence change or phase change materials, can be integrated in nanoelectrode configurations in order to explore their functionality for RS applications. This review discusses the RS properties of such nanoparticles by means of selected examples of both nanoparticle assemblies as well as on the individual particle level. Although this field of research is rather unexplored, it becomes evident that chemically tailored nanoparticles bear great potential for RS applications.

Investigation of resistive switching behaviors of cuprous phosphide thick film

In order to find high-performance memristor materials. we prepared cuprous phosphide (Cu3P) thick film by a simple chemical reaction method and studied its resistive switching properties. We investigated the effects of device structure, voltage sweep rate and electrode material on the resistive switching performance. For devices employing various electrode materials, negligible disparities were observed in transition voltage (< 0.35 V), endurance (2 ×103), and retention time (> 4 ×104 s). However, substantial differences were observed in operational speed and Off/On ratio. Specifically, device utilizing stainless steel (SS) electrode exhibited the highest operational speed (5000 V/s), while that employing nickel electrode demonstrated the largest Off/On ratio (2.1 ×104). We also observed that the device status self-healed after a voltage sweep operation. Finally, we discussed electrical switching mechanism. Our work enriches the resistive switching performance and mechanism of Cu3P bulk materials, hoping to provide a reference for the research of memristor materials.

Resistive switching properties of CdTe/CdSe core–shell quantum dots incorporated organic cow milk for memory application

Our study focuses on the resistive switching memory characteristics of devices containing active layers of CdTe/CdSe core–shell quantum dots (QDs) dispersed in organic cow milk. We fabricated devices containing CdTe/CdSe particles per volume of milk using a direct-dipping method, with particle concentrations of 2.4 × 10[Formula: see text] (S1), 4.8 × 10[Formula: see text](S2), and 7.2 × 10[Formula: see text](S3). This method was cost-free. Distinct memory characteristics were observed among devices featuring these concentrations. S1- and S2-based devices exhibited memory behavior with ‘S-type’ and ‘O-type’ hysteresis, respectively. The device based on S3 exhibited an initial asymmetric ‘N-type’ behavior with a large ON/OFF ratio ([Formula: see text]104). The memory attribute of the aforementioned device disappeared after the initial three cycles but was subsequently restored by modifying the scan voltage step from 10 mV to 1 mV. The observed results indicate typical symmetric ‘N-type’ behavior of the device, accompanied by threshold switching under positive voltage bias. Additionally, the switching was observed to be as low as 0.04 V. The S1- and S2-based devices were found to exhibit hopping conduction and Schottky emission in the OFF- and ON-state, respectively, while the S3-based device showed conductive bridge resistive switching as the conduction mechanism. The findings indicate that it is possible to produce biodegradable and disposable memory devices using full cream cow milk and CdTe/CdSe core–shell QDs. The device’s switching and memory functions can be manipulated by regulating the quantity of CdTe/CdSe particles present in the milk. Finally, we have demonstrated that the switching behavior of ReRAMs based on milk can be influenced by the voltage steps used during scanning.

Impact of Ag concentration in As-S-Se chalcogenide on physical, topological and resistive switching properties

Physical properties of quaternary chalcogenide Agx(As40S30Se30)100-x, glasses were analyzed. Synthesis of the studied samples x = 6 - 9 at.% Ag was performed by melt quenching in cascade regime of heating. X-ray diffraction analysis verified amorphous character of the synthesized samples. Morphological characterization was carried out using a scanning electron microscopy, and energy-dispersive X-ray mapping. The obtained results show that the density of the system increases upon silver incorporation in the glassy As40S30Se30 matrix, which is manifested through decrease of free volume percentage. Assessment of various physical and topological properties of prepared series of chalcogenide materials was done using theoretical models available in the literature. Specifically, compactness, average coordination number, constraint parameters, cross-linking density, floppy modes, number of lone–pair electrons are analyzed with addition of Ag atoms in the As40S30Se30 matrix. Average single bond energy and the mean bond energy were also discussed. The chemical bond approach model was used to study the cohesive energy of the studied Ag-containing As-S-Se samples. It is found that all studied parameters are dependent upon silver concentrations. Finally, the room-temperature memristive characteristics and compositional dependence on resistive switching properties in a wide range of Ag concentrations were examined in this paper.

Influences of Cu Doping on the Microstructure, Optical and Resistance Switching Properties of Zinc OxideThin Films.

Copper-doped zinc oxide films (Zn1-xCuxO) (x = 0, 2%, 4%, 6%) were fabricated on conductive substrates using the sol-gel process. The crystal structure, optical and resistive switching properties of Zn1-xCuxO films are studied and discussed. RRAM is made using Zn1-xCuxO as the resistive layer. The results show that the (002) peak intensity and grain size of Zn1-xCuxOfilms increase from 0 to 6%. In addition, PL spectroscopy shows that the oxygen vacancy defect density of Zn1-xCuxO films also increases with the increase in Cu. The improved resistive switching performance of the RRAM device can be attributed to the formation of conductive filaments and the destruction of more oxygen vacancies in the Zn1-xCuxO film. Consequently, the RRAM device exhibits a higher low resistance state to high resistance state ratio and an HRS state of higher resistance value.

Effect of Annealing on Resistive Switching Properties of Glancing Angle Deposition‐Assisted WO3 Thin Films

Herein, the impact of postdeposition annealing on resistive switching behavior of radio frequency magnetron sputtered WO3 thin films is reported. Films are deposited under glancing angle deposition (GLAD) configuration of sputtering at varying GLAD angle from 65° to 80°. Structure transition from monoclinic to orthorhombic phase in deposited WO3 films is perceived after ex situ annealing at temperature of 400 °C. Resistive switching properties show shift from bipolar to unipolar switching on postdeposition annealing. WO3 films show unipolar switching behavior after ex situ annealing for all prepared samples. The value of resistance in high resistance state is lowered after ex situ heating treatment and interestingly switching voltage also reduces to 3 V from 7 V after annealing treatment. The ratio of high to low resistance state for annealed WO3 film fabricated at 70° GLAD angle is achieved to be maximum (≈219). A detailed charge transport mechanism shows that ohmic behavior is dominant current conduction mechanism at lower applied voltage, while space charge limited current and Child's law are dominant at higher applied voltages. Obtained results encourage utilization of prepared WO3 thin films toward a wide variety of applications in optoelectronics, microelectronics, and environmental engineering along with advanced electronics such as resistive memory devices.

Double-Forming Mechanism of TaOx-Based Resistive Memory Device and Its Synaptic Applications.

The bipolar resistive switching properties of Pt/TaOx/InOx/ITO-resistive random-access memory devices under DC and pulse measurement conditions are explored in this work. Transmission electron microscopy and X-ray photoelectron spectroscopy were used to confirm the structure and chemical compositions of the devices. A unique two-step forming process referred to as the double-forming phenomenon and self-compliance characteristics are demonstrated under a DC sweep. A model based on oxygen vacancy migration is proposed to explain its conduction mechanism. Varying reset voltages and compliance currents were applied to evaluate multilevel cell characteristics. Furthermore, pulses were applied to the devices to demonstrate the neuromorphic system's application via testing potentiation, depression, spike-timing-dependent plasticity, and spike-rate-dependent plasticity.