Resistive Switching Effect Research Articles

Resistive Switching Effect in TaN/HfOx/Ni Memristors with a Filament Formed under Local Electron-Beam Crystallization

Resistive Switching Effect in TaN/HfOx/Ni Memristors with a Filament Formed under Local Electron-Beam Crystallization

Thickness-dependent microstructure, resistive switching, ferroelectric, and energy storage properties of pulsed laser deposited 0.85[0.6Ba(Zr0.2Ti0.8)O3-0.4(Ba0.7Ca0.3)TiO3]-0.15SrTiO3 thin films

In this work, we have studied the effect of thickness on structural, morphological, resistive switching (RS), ferroelectric, and energy storage properties of 0.85[0.6Ba (Zr0.2Ti0.8)O3-0.4(Ba0.7Ca0.3)TiO3]-0.15SrTiO3 (BZCT-STO) thin films deposited by the pulsed laser deposition technique. X-ray diffraction (XRD) analysis suggests that BZCT-STO thin films exhibit a polycrystalline tetragonal structure. The lattice parameters and tetragonality ratio approaching to bulk value with an increase of thickness, confirm strain relaxation in thicker films. SEM analysis reveals a dense columnar structure with a different grain size that varies from 3 nm to 60 nm as thickness increased from 160 to 360 nm. The P-E loops suggest that the relaxor behaviour increases with a decrease of thickness due to interface low dielectric layer, substrate clamping effect, small grain size, and high back switching ratio. The RS effect observed in Pt/BZCT-STO/Au capacitors is attributed to polarization modulation of the Schottky barrier and is found to be significant at low thickness. The effect of electric field and frequency on energy storage properties of BZCT-STO films is also investigated. The Pt/BZCT-STO/Au capacitor with a thickness of 160 nm exhibited 6.0 J/cm3 with an efficiency of 72% at a field of 800 kV/cm. It also exhibited a robust energy storage performance in the frequency range of 50–2000 Hz and also up to 108 cycles passing through the capacitor.

Resistive switching behavior in ZnO:Ca thin films deposited by a pulsed laser deposition technique

Calcium-doped ZnO (CZO) nanopowders were synthesized using the sol–gel method. The structural characteristics were investigated by X-ray diffraction (XRD) and the analysis reveals that our samples are crystalized in a wurtzite hexagonal structure. The morphological properties and the chemical composition of the nanoparticles were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The obtained powders are stoichiometric with crystallites in a nanometric scale aggregated in micrometric particles. Then, pulsed laser deposition (PLD) technique was used to grow Ca-doped ZnO thin films with different doping concentrations (1, 3, and 5%), on p-type Si substrates. The Ca doping effect on the electrical properties of the CZO films was investigated by current–voltage characteristics. A resistive switching (RS) effect was observed in the ITO/ZnO:Ca/Au structures. The RS behavior is dependent on the Ca doping concentration. The charge transport mechanisms of the devices were studied. In the positive bias voltage region, the transport is dominated by Ohmic and space-charge limited conduction mechanisms under low and high electric fields, respectively.

Write-once-read-many-times memory device based on Pt/BiFeO3/LaNiO3 heterostructures

Nonvolatile memory devices based on resistive switching effects are promising candidates for next generation high performance nonvolatile data storage. Here, we report the write-once-read-many-times (WORM) resistive switching behavior for the first time in Pt/BiFeO3/LaNiO3 heterostructures. BiFeO3 thin films with (100) preferred orientation have been prepared by RF magnetron sputtering combined with annealing at temperature higher than 600 ℃, and show excellent WORM resistive switching behaviors with data retention for>3600 s and reliable endurance for>1000 cycles. The devices with BiFeO3 annealed at 650 ℃ exhibit extremely high ON/OFF ratio (>3 × 104) and low switching voltage (∼3 V) due to the high quality of BiFeO3 thin films. The observed resistive switching behavior is attributed to the formation of permanent conducting filaments that composed of oxygen vacancies. These results demonstrate that BiFeO3 is promising for novel WORM memory device applications.

High-performance and humidity robust multilevel lead-free all-inorganic Cs3Cu2Br5 perovskite-based memristors

Halide perovskites have attracted surge of interest in the memristor field due to their superior electrical property and corresponding remarkable device performances. However, the issues of toxicity and unstable properties still severely restrict their potential applications. Here, the lead-free all-inorganic perovskite Cs3Cu2Br5 films are adopted as the switching layer to fabricate memristors with Al/Cs3Cu2Br5/ITO structure. The prepared Al/Cs3Cu2Br5/ITO memristors exhibit typical reproducible bipolar resistive switching (RS) behavior with striking characteristics, including ultralow operating voltages (0.45, −0.39 V), moderate high resistance state/low resistance state ratio (≈102), and remarkable retention time (>104 s). In addition, the multilevel storage capability can be achieved by controlling compliance current. The RS effect, stemming from the formation/rupture of both localized conductive Br vacancy/Al atom filaments, is proposed to illustrate the memristors. More importantly, the RS behavior of Al/Cs3Cu2Br5/ITO memristors maintains robustness in harsh environments with humidity up to 80%, enabling secure hardware applicable in extreme environments. This work demonstrates the opportunity for exploring the next-generation nonvolatile memories based on lead-free all-inorganic halide perovskites in future environmental-friendly and humidity robust electronics.

Air‐Stable, Eco‐Friendly RRAMs Based on Lead‐Free Cs3Bi2Br9 Perovskite Quantum Dots for High‐Performance Information Storage

Development of lead‐free halide perovskites that are innocuous and stable has become an attractive trend in resistive random access memory (RRAM) fields. However, their inferior memory properties compared with the lead‐based analogs hinder their commercialization. Herein, the lead‐free Cs3Bi2Br9 perovskite quantum dot (PQD)‐based RRAMs are reported with outstanding memory performance, where Cs3Bi2Br9 quantum dots (QDs) are synthesized via a modified ligand‐assisted recrystallization process. This is the first report of applying Cs3Bi2Br9 QDs as the switching layer for RRAM device. The Cs3Bi2Br9 QD device demonstrates nonvolatile resistive switching (RS) effect with large ON/OFF ratio of 105, low set voltage of −0.45 V, as well as good reliability, reproducibility, and flexibility. Concurrently, the device exhibits the notable tolerance toward moisture, heat and light illumination, and long‐term stability of 200 days. More impressively, the device shows the reliable light‐modulated RS behavior, and therefrom the logic gate operations including “AND” and “OR” are implemented, foreboding its prospect in logic circuits integrated with storage and computation. Such multifunctionality of device could be derived from the unique 2D layered crystal structure, small particle size, quantum confinement effect, and photoresponse of Cs3Bi2Br9 QDs. This work provides the strategy toward the high‐performance RRAMs based on stable and eco‐friendly perovskites for future applications.

J-V characteristics of sol-gel-prepared Zn2+ doped LiNbO3

Herein, a stable LiNbO3 (LN) sol, with different Zn2+ contents, is prepared using ethanol niobium, lithium acetate and zinc acetate as starting materials, absolute ethanol as a solvent, and acrylic acid and benzoyl acetone (BzAcH) as additives. The influence of Zn2+ content on LN crystal structure, light transmittance and J-V curve characteristics is studied in detail. XRD results reveal that Zn2+ doping, with a molar content of less than 5%, does not influence the crystal structure of LN. SEM indicates that the grain size of LN films gradually increases with the increase of doping content. The surface quality of LN films becomes worse when the doping content of Zn2+ reaches 5%. Moreover, light transmittance tests show that the maximum light transmittance is attained at the doping amount of 3%. J-V curves demonstrate that Pt/LN/LNO(LaNiO3) structure shows excellent resistance switching (RS) effect due to the formation of Schottky barrier at the Pt/LN interface, which initially becomes prominent with the increase of Zn2+ content, followed by a gradual decrease. On the other hand, In/LN/LNO structure exhibits poor RS effect due to the unobvious Schottky barrier at In/LNO interface. Furthermore, J-V curves at different temperatures demonstrate that the RS effect of Pt/LN/LNO structure tends to deteriorate, while the refractive index of LN film increases with the decrease of temperature. Herein, the abovementioned RS phenomenon is analyzed and explained in terms of the relationship between interfacial barrier and doping amount of Zn2+, migration of oxygen vacancies, and the relationship between insulation property of LN films and temperature. The research results are of experimental and theoretical significance for practical applications of LN films.

Dielectric and bipolar resistive switching properties of Ag doped As–S–Se chalcogenide for non-volatile memory applications

In this study, dielectric and bipolar resistive switching properties of the chalcogenide from the Ag–As40S30Se30 system were investigated for potential application in non-volatile memory devices. Preparation of the glasses was done with the use of melt-quenching technique. Current–voltage (I–V) characteristics were determined at different temperatures, and stability of the Ag/chalcogenide sample/Ag structure through constant value of memory window was noticed. Namely, it was observed that a bipolar resistive switching effect is present in the prepared samples with noticeable transitions between high-resistance and low-resistance states when the voltage polarity was changed. Temperature dependent I–V measurements indicated that resistive switching voltage decreases as temperature increases suggesting thermally activated motion of charge carriers. The conduction model fitting results suggested that the Ohmic and space-charge limited current conduction are responsible for resistive switch. Based on the analysis of the obtained results, resistive switching mechanism was explained by using filamentary conduction. In addition, study of dielectrical properties indicated presence of space charge polarization. The presented results show that the synthesized material has properties that suggest them for potential application in non-volatile memory devices.

Coexistence mechanisms of negative differential resistance and resistive switching effects in a WOx-based memristor

Metal oxide memristors are highly desirable for bionic synaptic applications.

High endurance organic resistive switching memory based on 1, 2-dicyanobenzene and polymer composites

As the emerging data storage technology, organic resistive switching memory (ORSM) possesses numerous superiorities as the substitution for or the complementation of the traditional Si-based semiconductor memory. Poly(3-hexylthiophene) (P3HT) has been widely used as a polymer donor component of ORSMs due to its advantages of high mobility and high chemical stability. Up to now, ORSM based on P3HT has achieved high on/off current ratio (<i>I</i><sub>on/off</sub>), but the endurance still needs to be improved. Herein, high endurance ORSMs based on 1,2-dicyanobenzene (O-DCB) and P3HT composite are fabricated by spin coating and thermally evaporating, and exhibit non-volatile and bipolar memory characteristics. The ORSMs based on P3HT:15 wt.% O-DCB and P3HT:30 wt.% O-DCB exhibit the values of <i>I</i><sub>on/off</sub> exceeding 10<sup>4</sup> and 10<sup>3</sup> respectively, and both of them exert excellent endurance of 400 times, retention time of more than 10<sup>5</sup> s. The mechanism of the switching is explored by linear fitting of <i>I-V</i> curve and electrochemical impedance spectrum . The results indicate that the filling and vacant process of the charge traps induced by O-DCB and the inherent traps in P3HT bulk lead to a resistive switching effect. The negative or positive bias triggers off trapping and detrapping process, which leads the conductive way of charges to change, resulting in the resistive switching effect. The excellent endurance of ORSM is attributed to the uniform distribution of O-DCB in P3HT bulk because of the small molecular size and high solubility of O-DCB, resulting in well-distributed and stable charge traps. On the other hand, the out-bound planarity of O-DCB molecular promotes the close interaction with the conjugated chains of P3HT. This study enlightens an effective strategy to carry out high-endurance ORSM and facilitates their electronic applications in future.

Структурные и электрофизические свойства композитных мемристоров на основе матрицы LiNbO-=SUB=-3-=/SUB=- с разными наногранулами: Co-Fe-B и CoFe

Comparative studies of the properties of metal/nanocomposite/metal (M/NC/M) memristive structures based on NC consisting of a LiNbO 3 matrix and various Co-Fe-B or CoFe metal granules have been carried out. The M/NC/M structures were obtained using ion-beam sputtering from composite targets Co 40 Fe 40 B 20 -LiNbO 3 and Co 50 Fe 50 -LiNbO 3 on glass-ceramic substrates. The same NC layers were synthesized on polyimide substrates to study the structural features by X-ray absorption fine structure spectroscopy (XAFS). The XAFS data show an identical crystal structure of granules in both types of NC, indicating that a significant part of the B atoms during the synthesis of NC is in an insulating matrix, forming an oxide of the B 2 O 3 type, which is confirmed by X-ray photoelectron spectroscopy data. In this case, no metallic state of niobium is observed in the layers. Both types of M/NC/M structures demonstrate resistive switching (RS), however, in the case of NC with boron, the RS effect is much stronger, which is explained by the significant role of oxygen vacancies formed during the oxidation of boron in the RS.

Evolution between CRS and NRS behaviors in MnO2@TiO2 nanocomposite based memristor for multi-factors-regulated memory applications

Capacitive-coupled memristive effect provides a favorable way for developing novel multifunctional device since it simultaneously exhibits capacitive behavior and resistive switching (RS) effect. Herein, the memristive device with an Ag/MnO2@TiO2/FTO sandwich structure was fabricated, in which the MnO2@TiO2 nanocomposite with different thicknesses was deposited on F-doped SnO2 (FTO) substrates by hydrothermal method. It was observed that the device exhibits the evolution between capacitive-coupled RS (CRS) effect and negative differential resistance (NDR)-coupled RS (NRS) effect by tuning the MnO2 thickness and applied voltage. Through in-depth mechanistic analysis, it was inferred that the evolution behaviors are attributed to the interaction of ions and electrons in the MnO2@TiO2 nanocomposite. With the dielectric capacity of the functional layer increases, the migration of ions and electrons is hindered, which impairs the formation of conductive filaments (CFs), causing a large number of electrons/ions to collect on the interfaces of the functional layer/electrodes, resulting in an internal electric field, thereby observing a macroscopic capacitive effect. Therefore, this work provides a deep understanding of the evolution between CRS and NRS effects, opening a new way for building ultra-low-power multifunctional device for artificial intelligence applications.

Optical and structural properties of gradient (Ti,Co)Ox thin-film coatings with a resistive switching effect.

In this work, the optical and structural properties of gradient (Ti,Co)Ox coatings with a resistive switching effect have been outlined. They were prepared using multi-magnetron sputtering and, despite the high cobalt content, they were transparent and had a high refractive index. The gradient Co-addition resulted in the receiving of fine crystalline T i O 2-anatase and C o 3 O 4 forms in the amorphous surrounding. Observed resistance switching was a fully repeatable effect, and its occurrence in gradient (Ti,Co)Ox coatings has not reported earlier. The prepared gradient coatings exhibit great potential as transparent electronic devices with the resistance switching effect. Such memory effects in transparent thin-film coatings open new possibilities for the manufacturing of innovative memory elements in the future.

Polarized neutron reflectometry study on the modulation of resistance and magnetism in resistive switching cobalt ferrite thin films

In this work, the resistive switching and electrical-control of magnetization in Pt/CoFe2O4/Nb:SrTiO3 heterostructures have been investigated. The films exhibit a classic bipolar resistive switching effect with a maximum switch ratio of about 5 × 103 and good anti-fatigue performance. Associated with resistive switching, the saturated magnetization of the thin film at high resistance state is found to be larger than that at low resistance state. Meanwhile, polarized neutron reflectivity of the thin film under different resistance states was in situ measured. The results reveal that the interfacial migration of oxygen vacancies driven by an applied electric field plays an important role in the modulation of resistive and magnetism of CoFe2O4 resistive switching devices.

Self-rectifying effect in Au/Al2O3/Si resistive memory structure

To solve the crosstalk problem when the integration density of resistive random access memory (RRAM) devices increase, RRAM with self-rectifying function is required. Herein, the Au/10 nm Al2O3/heavily doped p-type Si (p++-Si) structure was fabricated, and bipolar resistive switching and self-rectifying effect were investigated. A rectification of 6.5 × 103 under ±5 V at low-resistive state (LRS) was observed. The rectifying effect is explained by the energy band diagrams of the structure and electrical conduction mechanism at LRS under negative bias is fitted by space charge limited conduction (SCLC) model. Finally, the endurance and retention properties of the structure were tested. This work would provide insights for further research on the RRAM device with self-rectifying effect, which can alleviate the crosstalk effect without additional switching elements in integrated circuit.

Three-state resistive switching effect in BiFeO3 thin films

Resistive switching (RS) memristor has been widely used in the in-memory computation systems. Due to the strong information processing capability and low area cost of the ternary logic, the development of the three-state RS memristor was promoted. Here, we demonstrate a three-state RS phenomenon on Pt/BiFeO3/SrRuO3 structure. After applying a positive voltage to the thin film for a period, an abrupt RS effect occurs, where the three-state RS behavior can be obtained. By analyzing the conduction mechanisms of the current-voltage curves and the behavior of the capacitance-voltage curves, the three-state storage capability of the memristor can be ascribed to the movement of oxygen vacancies and the trapping/detrapping of charge carriers at the interface. The ternary OR logic gate was also designed with three steps by using only one memristor.

Study of dielectric and electrical properties in Co-(Fe–Ce-Nd) nanosized spinel ferrites

Ce–Nd doped Cobalt ferrite nanoparticles having composition CoFe2-2xCexNdxO4 (where 0.00 ≤x ≤ 0.10) were prepared by co-precipitation method. X-ray diffraction study confirms the formation of single-phase spinel ferrite. Temperature dependent dielectric and electrical properties has been studied with in the frequency range of 20Hz to 3 MHz. Dielectric constant and dielectric loss decrease as frequency increased while ac conductivity exhibit increasing trend with increasing frequency. The alternating current (AC) conductivity data were successfully modeled by using universal Jonscher's power law which implies that hopping of charge carriers is the governing mechanism in the conduction. Impedance study using Nyquist plots shows that grain boundary resistance is higher than the grain interior resistance. Diameter of Nyquist plots decreases with increasing temperature indicating the decrease in impedance and increase in conductivity. DC resistivity show decreasing trend with increasing temperature revealing semiconductor nature of synthesized nanoparticles. Current–Voltage measurements exhibit nonlinear hysteresis loop which authenticate the occurrence of resistance switching effect in synthesized composition.

Investigations on resistive switching effect and time series statistical analysis of solution combustion synthesized ZnTiO3 memristive device

Investigations on resistive switching effect and time series statistical analysis of solution combustion synthesized ZnTiO3 memristive device

Influence of spinel ZnMn2O4 particles on the dielectric performance of PVDF‐based composites

AbstractSpinel ZnMn2O4 are widely used in lithium batteries, sensors, and catalysis due to its electrical and magnetic properties. However, the influence of the resistive switching effect on the dielectric properties of the polymer matrix induced by ZnMn2O4 has not been investigated in depth. In this study, spinel ZnMn2O4 powders were synthesized via the hydrothermal method, and ZnMn2O4/PVDF composites were prepared for research the influence of ZnMn2O4 particles on dielectric performance of PVDF‐based composites. The existence of ZnMn2O4 particles improves the dielectric constant slightly, while enhances the breakdown strength of composites significantly. The maximum value of breakdown strength achieved in composite with 10 wt% ZnMn2O4 is 108 kV/mm, which is five times larger than that of undoped PVDF. The enhanced dielectric properties are attributed to the quasi‐Coulomb blockade effect induced by the resistive switching effect of ZnMn2O4 particles under applied electric field. The results presented in this work indicate the promising of ZnMn2O4 particles in dielectric and insulating composites.

Anomalous dielectric relaxation peak in Nb-doped SrTiO3 single crystals

Anomalous dielectric relaxation appears in Nb-doped SrTiO3 (SNT) single crystal with relaxation rate displaying unusual slowing down with increasing temperature. Dielectric measurements show that the resistivity increases with temperature. Raman spectrum and the spherical aberration-corrected transmission electron microscope (STEM) show the existence of polar nano regions (PNRs) in the crystal. The temperature-dependence of DC conductivity and current-voltage (I–V) curves suggest that this anomalous behavior happens at the interfaces of PNRs. The evolution of the anomalous relaxation peak in the annealed samples indicates that this effect is simultaneously affected by the carrier concentration and the interface structure. The anomalous dielectric relaxation is reminiscent of the positive temperature coefficient of resistance (PTCR) effect in a polycrystalline material. The resistive switching effect makes such materials to have potential application value in switches, sensors, and device miniaturization.