Robust Endurance Research Articles

Charge-Selective 2D Heterointerface-Driven Multifunctional Floating Gate Memory for In Situ Sensing-Memory-Computing.

Flash memory, dominating data storage due to its substantial storage density and cost efficiency, faces limitations such as slow response, high operating voltages, absence of optoelectronic response, etc., hindering the development of sensing-memory-computing capability. Here, we present an ultrathin platinum disulfide (PtS2)/hexagonal boron nitride (hBN)/multilayer graphene (MLG) van der Waals heterojunction with atomically sharp interfaces, achieving selective charge tunneling behavior and demonstrating ultrafast operations, a high on/off ratio (108), extremely low operating voltage, robust endurance (105 cycles), and retention exceeding 10 years. Additionally, we achieve highly linear synaptic potentiation and depression, and observe the reversibly gate-tunable transitions between positive and negative photoconductivity. Furthermore, we employed the VGG11 neural network for in situ trained in-sensor-memory-computing to classify the CIFAR-10 data set, pushing accuracy levels comparable to pure digital systems. This work could pave the way for seamlessly integrated sensing, memory, and computing capabilities for diverse edge computing.

Robust resistance switching performance in a Ca3Ti2O7/La0.67Sr0.33MnO3 heterostructure induced by the interface

Ruddlesden–Popper phase oxides, such as Ca3Ti2O7, have been established as hybrid improper ferroelectrics. However, investigations into Ca3Ti2O7 have primarily concentrated on their structural and ferroelectric properties. In this study, we prepared epitaxial Ca3Ti2O7 thin films via magnetron sputtering. Conducting atomic force microscopy was employed to characterize local current variations under an applied bias voltage. Electron paramagnetic resonance measurements of the Ca3Ti2O7/La0.67Sr0.33MnO3 film were conducted to assess its defect characteristics. Interestingly, the Ca3Ti2O7/La0.67Sr0.33MnO3 stacks exhibited remarkable macroscopic resistance switching, with a resistance on/off ratio reaching 100, alongside robust retention (∼2500 s) and endurance (∼2000 cycles) features. Additionally, density functional theory calculations suggest that the resistance switching is attributable to the interface barrier of the Ca3Ti2O7/La0.67Sr0.33MnO3 interface and the efficacy of space charge limitation. This work proposes an avenue for the utilization of Ruddlesden–Popper phase Ca3Ti2O7 in various applications.

Reconfiguring Zn2+ Solvation Network and Interfacial Chemistry of Zn Metal Anode with Molecular Engineered Crown Ether Additive

AbstractThe practical deployment of rechargeable aqueous zinc‐ion batteries (RAZBs) in the scaled power system suffers from unregulated Zn dendrite growth as well as parasitic reactions at the zinc foil/aqueous electrolyte interface, leading to insufficient zinc utilization and severe electrode corrosion. Herein, a novel crown ether additive is developed, with tailored molecular engineering, to stepwise regulate the Zn2+ solvation network and interfacial chemistry of Zn metal anode. The designed crown ether (C5SeCN), featuring zincophilic cyano group and hydrophobic selenium, efficiently reconstructs the solvation sheath of Zn ions at the 0.3 wt.% dose amount. Additionally, the ozone plasma treatment tethers the O2‐ groups onto the thin‐layer zinc foil, which thus binds Se atoms of the C5SeCN to the Zn anode. The Zn||Zn symmetric cells exhibit a lifespan of over 4500 h at 1 mA cm−2 and high current density endurance of up to 10 mA cm−2. Moreover, the 2 mAh cm−2 Zn||V2O5 full cell model, at the low N/P ratio of 2.8 with a lean electrolyte (E/C ratio = 10 µL mAh−1), enables robust cycling endurance at 2 A g⁻¹ for 300 cycles. This study unravels the interfacial design rationales for maximizing zinc utilization and highlights the commercial potential of crown ether additives for RAZBs development.

Charge transfer complex induced confinement effect between organic semiconductor and polymer chains for enhancing high-temperature capacitive energy storage

High-temperature polymer dielectrics, renowned for their ultrahigh power densities, robust voltage endurance, and remarkable reliability, present significant potential in optimizing the functionality of microelectronics and electrical power systems. Herein, to elucidate a notable correlation between the confinement effect induced by charge transfer complexes (CTCs) and the discharged energy density (Ue), a series of PI-based composites were synthesized, integrating organic semiconductors with diverse electron affinities. The density functional theory (DFT) simulations revealed that escaping from the CTCs required higher activation energy, besides, a more pronounced electron localization function was observed in the interfacial region between PI chain and F6TCNNQ in comparison to pristine PI, PI/F2TCNQ, and PI/F4TCNQ. Consequently, the CTCs present in PI/F6TCNNQ exhibit the greatest electron localization, significantly impeding electron transport within the composite. Furthermore, at 200 °C, the Ue for the PI/F6TCNNQ composite remains notably high at 5.06 J cm−3 with an efficiency above 90 %, representing a 2.45-fold increase compared to that of pristine PI (2.03 J cm−3). The findings provide evidence for a positive correlation between the confinement effect induced by CTCs and the discharged energy density (Ue) of the composite materials at elevated temperatures, thus offering valuable insights for future investigations focused on all-organic dielectric composite materials.

Enhancing mechanical and thermal properties of polyvinyl alcohol/curdlan composite hydrogels and aerogels via freeze-casting technique

This study introduces a novel approach to fabricating polyvinyl alcohol (PVA)/curdlan (CURD) composite aerogels by employing the freeze-casting technique to achieve exceptional mechanical and thermal properties. Our research demonstrated that the formation of dual-network structure that combines the mechanical strength of PVA with the thermal stability of CURD. Scanning electron microscopy revealed a unique honeycomb-like cross-sectional morphology in the PVA/CURD aerogels. Notably, the PVA/CURD composite hydrogel demonstrated consistent compressive stress performance even after 50 compression cycles and exhibited minimal swelling (only 4%) when immersed in distilled water for 24hours. Furthermore, the aerogels exhibited varying swelling ratios in different pH environments, with a significant increase observed in acidic conditions. Thermal analysis confirmed the enhanced thermal stability of the composite aerogels, attributed to the incorporation of CURD. These findings suggest that PVA/CURD composite aerogels have promising applications in fields that require materials with robust mechanical and thermal endurance.

Quasi-equilibrium growth of inch-scale single-crystal monolayer α-In2Se3 on fluor-phlogopite

Epitaxial growth of two-dimensional (2D) materials with uniform orientation has been previously realized by introducing a small binding energy difference between the two locally most stable orientations. However, this small energy difference can be easily disturbed by uncontrollable dynamics during the growth process, limiting its practical applications. Herein, we propose a quasi-equilibrium growth (QEG) strategy to synthesize inch-scale monolayer α-In2Se3 single crystals, a semiconductor with ferroelectric properties, on fluor-phlogopite substrates. The QEG facilitates the discrimination of small differences in binding energy between the two locally most stable orientations, realizing robust single-orientation epitaxy within a broad growth window. Thus, single-crystal α-In2Se3 film can be epitaxially grown on fluor-phlogopite, the cleavage surface atomic layer of which has the same 3-fold rotational symmetry with α-In2Se3. The resulting crystalline quality enables high electron mobility up to 117.2 cm2 V−1 s−1 in α-In2Se3 ferroelectric field-effect transistors, exhibiting reliable nonvolatile memory performance with long retention time and robust cycling endurance. In brief, the developed QEG method provides a route for preparing larger-area single-crystal 2D materials and a promising opportunity for applications of 2D ferroelectric devices and nanoelectronics.

Mechanisms for enhanced ferroelectric properties in ultra-thin Hf0.5Zr0.5O2 film under low-temperature, long-term annealing

To gain insight into the ferroelectric mechanisms under reduced thermal budget and thickness scaling, a 4.6 nm ultra-thin ferroelectric Hf0.5Zr0.5O2 capacitor compatible with back-end-of-line (BEOL) processes (all conducted at temperatures ≤350 °C) is investigated in this work. Through O3 pretreatment at the bottom electrode (BE) interface and controlled temperature modulation of the crystalline phase, the capacitor exhibits exceptional ferroelectric (FE) properties following low-temperature (350 °C) and long-term (300 s) rapid thermal annealing (RTA). These properties include high remanent polarization (2Pr ∼ 28.53 μC/cm2), low coercive voltage (Vc ∼ 0.43 V), effective leakage suppression, robust endurance (∼1010 cycles without hard breakdown), and a desirable high dielectric constant. The main mechanisms identified include tetragonal phase nucleation under enhanced tensile stress via the oxidized BE layer (TiO2), crystalline growth controlled through RTA temperature modulation, and phase transition to the ferroelectric orthorhombic phase under electric field cycling. This research provides valuable insights for the development of BEOL-compatible nonvolatile FE memories.

Multilevel Conductance States of Vapor-Transport-Deposited Sb2S3 Memristors Achieved via Electrical and Optical Modulation.

The pursuit of advanced brain-inspired electronic devices and memory technologies has led to explore novel materials by processing multimodal and multilevel tailored conductive properties as the next generation of semiconductor platforms, due to von Neumann architecture limits. Among such materials, antimony sulfide (Sb2S3) thin films exhibit outstanding optical and electronic properties, and therefore, they are ideal for applications such as thin-film solar cells and nonvolatile memory systems. This study investigates the conduction modulation and memory functionalities of Sb2S3 thin films deposited via the vapor transport deposition technique. Experimental results indicate that the Ag/Sb2S3/Pt device possesses properties suitable for memory applications, including low operational voltages, robust endurance, and reliable switching behavior. Further, the reproducibility and stability of these properties across different device batches validate the reliability of these devices for practical implementation. Moreover, Sb2S3-based memristors exhibit artificial neuroplasticity with prolonged stability, promising considerable advancements in neuromorphic computing. Leveraging the photosensitivity of Sb2S3 enables the Ag/Sb2S3/Pt device to exhibit significant low operating potential and conductivity modulation under optical stimulation for memory applications. This research highlights the potential applications of Sb2S3 in future memory devices and optoelectronics and in shaping electronics with versatility.

Integrating Electroencephalography with Motophysic training: Assessing the shift in fitness and cognitive functions in elite youth soccer players

Motor and physical fitness play a crucial role to optimize the player performance in the soccer game. Implementing a customized workout schedule targeting Motophysic Fitness (MPF) helps to elevate their on-field performance. The present study was aimed to assess the impact of a 12-week MPF Training program targeted to have improvements in physical fitness for elite soccer players. MPF training program was implemented during the off-season for youth soccer players with average age (20 ± 1 years), height (1.75 ± 0.5 m) weight (64.3 ± 5.7 kg). Soccer-related fitness traits were assessed to evaluate performance levels, while Electroencephalography (EEG) was utilized for cognitive assessment. Statistical analysis was performed to evaluate the outcome of the fitness traits. Significant improvements were observed across diverse fitness traits, with mean values increasing by a minimum of 2 % and a maximum of 5 %. Speed emerged as a predominant contributor, showing a robust correlation (Adjusted R2 = 0.84), while agility, strength, power, endurance, balance, coordination, and reaction time also displayed substantial improvements. Despite observable gains in flexibility, its impact on overall fitness appeared comparatively modest (Adjusted R2 = 0.23). Z-test confirmed the statistical significance of all fitness assessments post-MPF, with p-values less than 0.05 for each test. Features extracted from EEG highlighted the improvement in cognitive ability before and after training.

Performance improvement of bilayer memristor based on hafnium oxide by Ti/W synergy and its synaptic behavior

Bilayer and multi-layer structures can effectively improve the performance of memristors, but the oxide/metal interface during the resistance switching process affects its reliability and stability. In this work, the Pt/HfO2/HfOx/W and Pt/HfO2/HfOx/Ti/W memristors with a homogeneous bilayer structure are compared to systematically investigate the effect of interface engineering on bilayer hafnium oxide devices by inserting Ti buffer layer to construct Ti/W composite electrode. Compared with the stimulated oxidation of the W electrode, the device under the synergy of Ti/W composite electrode showed better switching uniformity (The resistance of the high-resistance state and reset voltage variation coefficient decreased from 83.1 % to 31.9 % and from 9.5 % to 5.6 %, respectively.) and robust endurance (>104 cycles). Meanwhile, some essential synaptic behaviors such as nonlinear transmission characteristics, paired-pulse facilitation, and spike-timing-dependent plasticity were mimicked by using different pulse stimuli. Subsequently, the resistance switching mechanism of the device under the Ti/W synergy was explored by combining the results of I–V curve fitting and material analysis. These results provided important experimental guidance and a theoretical basis for further optimization of electrode interfacial effect in the future.

Innovative Recovery Strategy for MFIS-FeFETs at Optimal Timing With Robust Endurance: Fast-Unipolar Pulsing (100 ns), Nearly Zero Memory Window Loss (0.02%), and Self-Tracking Circuit Design

Innovative Recovery Strategy for MFIS-FeFETs at Optimal Timing With Robust Endurance: Fast-Unipolar Pulsing (100 ns), Nearly Zero Memory Window Loss (0.02%), and Self-Tracking Circuit Design

MAX Phase Ti2AlN for HfO2 Memristors with Ultra‐Low Reset Current Density and Large On/Off Ratio

AbstractA Ti2AlN MAX phase layered thin film electrode and oxygen getter layer for HfO2‐based two‐terminal memristors is presented. The Ti2AlN/HfOx/Ti memristor devices exhibit enhanced resistive switching performance, including an ultra‐low reset current density (< 10−8 MΩ cm2), substantial on‐off ratio (≈ 6000), excellent multi‐level functionality (≈ 9 distinct states), impressive retention (up to 300 °C), and robust endurance (>200 million) as compared to conventional TiN and other alternative materials based memristors. Experimental measurements and modeling suggest that the distinctive combination of low thermal conductivity, high electrical conductivity, and unique ultra‐thin layer‐by‐layer structure of the Ti2AlN MAX phase thin film contribute to this exceptional performance with good reproducibility and stability. The results demonstrate for the first‐time the potential of this innovative sputtered MAX phase material for engineering energy‐efficient, high‐density non‐volatile digital, and analog memory devices aimed toward next‐generation sustainable artificial intelligence.

Interface Engineering Enables Multilevel Resistive Switching in Ultra-Low-Power Chemobrionic Copper Silicate.

Memristor is assuming prominence due to its exceptionally low power consumption, adaptable, and parallel signal processing capabilities that address the limitations of the von Neumann architecture to meet the growing demand for advanced technologies such as artificial intelligence, Internet of Things (IoTs), and neuromorphic computation. In this work, we demonstrate resistive switching in copper silicate-based hollow tube-forming self-organized membrane structures belonging to the category of chemobrionics or chemical gardens to demonstrate cost-effective and highly efficient memristor devices. The device architecture is configured as ITO/PEDOT:PSS/active layer (copper silicate)/PMMA/Ag, an arrangement that serves to stabilize current-voltage hysteresis and exhibit a low SET voltage ∼0.2 V with a 0.8 nJ power consumption while manifesting robust data endurance and multilevel resistive switching. The inherent self-rectifying behavior, characterized by a high rectification ratio of 60, underscores the potential utility of these devices across a spectrum of electronic applications. To emulate the functionality of biological synapses, fundamental synaptic characteristics are assessed, including paired-pulse facilitation (PPF) and potentiation and depression (P&D). We validate the potential of copper silicate chemical garden-based memristor devices for applications that require real-time synaptic processing. Importantly, the fabrication of these devices was accomplished through a comprehensive solution-based, low-temperature process conducted under ambient environmental conditions, obviating the need for specialized glovebox facilities.

Near-sensor analog computing system based on low-power and self-assembly nanoscaffolded BaTiO3:Nd2O3 memristor

Near-sensor analog computing systems have received a lot of attention as they can effectively reduce the large amount of redundant data transferred between sensor terminals and computing units, thereby shortening the data processing time and reducing power consumption. However, ensuring the reliability and stability of memristor devices used in the hardware circuits of near-sensor analog computing systems remains a considerable challenge. In this paper, we describe a robust ferroelectric memristor based on Pd/BaTiO3:Nd2O3/La0.67Sr0.33MnO3 grown on a silicon structure with SrTiO3 as the buffer layer. Through optimized growth temperature, the device exhibits a low coercive field voltage (−1–2 V), robust endurance characteristics (>1010 cycles), and a power consumption as low as 0.45 fJ per synaptic event. Also in this study, a near-sensor analog computing system based on an array of pressure sensors and ferroelectric memristors was constructed. It is shown that this system can accurately calculate multiple raw analog pressure signals in real time without the need for peripheral circuitry and that the system can classify object shapes and perform edge detection with a maximum deviation of only about 58.6 nA. This study highlights the great potential of ferroelectric memristors for use as fundamental components of near-sensor analog computing systems.

Ovonic threshold switching-based artificial afferent neurons for thermal in-sensor computing.

Artificial afferent neurons in the sensory nervous system inspired by biology have enormous potential for efficiently perceiving and processing environmental information. However, the previously reported artificial afferent neurons suffer from two prominent challenges: considerable power consumption and limited scalability efficiency. Herein, addressing these challenges, a bioinspired artificial thermal afferent neuron based on a N-doped SiTe ovonic threshold switching (OTS) device is presented for the first time. The engineered OTS device shows remarkable uniformity and robust endurance, ensuring the reliability and efficacy of the artificial afferent neurons. A substantially decreased leakage current of the SiTe OTS device by nitrogen doping results in ultra-low power consumption less than 0.3 nJ per spike for artificial afferent neurons. The inherent temperature response exhibited by N-doped SiTe OTS materials allows us to construct a highly compact artificial thermal afferent neuron over a wide temperature range. An edge detection task is performed to further verify its thermal perceptual computing function. Our work provides an insight into OTS-based artificial afferent neurons for electronic skin and sensory neurorobotics.

High‐Performance Broadband Flexible Photodetectors Based on Ti3C2Tx MXene/Pyramidal Thin Si Heterostructures with Light Trapping Effect for Heart Rate Detection

AbstractHigh‐performance flexible photodetectors are urgently demanded for application in many emerging domains including flexible, wearable, portable, and stretchable optoelectronics. In this work, a highly efficient flexible photodetector made of a Ti3C2Tx MXene/pyramidal thin Si heterostructure is successfully fabricated. Thanks to the remarkable light trapping effect as confirmed by numerical modeling based on finite‐element method, the as‐constructed detector demonstrates excellent photoresponse performance in a broadband wavelength spectrum. The optimal responsivity, specific detectivity, and response speed reach ≈530 mA W−1, ≈1.21 × 1012 Jones and 30/14 µs, respectively, at zero bias under near‐infrared light illumination. Specifically, the responsivity is greatly enhanced by ≈2.65 times, as compared with a planar counterpart. In addition, the light detector can maintain its outstanding photoresponse properties upon 1000 cycles of bending test or at diverse bending radii of curvature, owing to its prominent mechanical flexibility and robust bending endurance. Finally, the capability of monitoring the heart rate of a person in a wideband wavelength spectrum and at various bending radii of curvature is presented. The above results imply the huge potential of the flexible light detector for use in some applications such as wearable health monitoring.

Simultaneously ultrafast and robust two-dimensional flash memory devices based on phase-engineered edge contacts

As the prevailing non-volatile memory (NVM), flash memory offers mass data storage at high integration density and low cost. However, due to the ‘speed-retention-endurance’ dilemma, their typical speed is limited to ~microseconds to milliseconds for program and erase operations, restricting their application in scenarios with high-speed data throughput. Here, by adopting metallic 1T-LixMoS2 as edge contact, we show that ultrafast (10–100 ns) and robust (endurance>106 cycles, retention>10 years) memory operation can be simultaneously achieved in a two-dimensional van der Waals heterostructure flash memory with 2H-MoS2 as semiconductor channel. We attribute the superior performance to the gate tunable Schottky barrier at the edge contact, which can facilitate hot carrier injection to the semiconductor channel and subsequent tunneling when compared to a conventional top contact with high density of defects at the metal interface. Our results suggest that contact engineering can become a strategy to further improve the performance of 2D flash memory devices and meet the increasing demands of high speed and reliable data storage.

A flexible Hf0.5Zr0.5O2 thin film with highly robust ferroelectricity

Flexible hafnia-based ferroelectric memories are arousing much interest with the ever-growing demands for nonvolatile data storage in wearable electronic devices. Here, high-quality flexible Hf0.5Zr0.5O2 membranes with robust ferroelectricity were fabricated on inorganic pliable mica substrates via an atomic layer deposition technique. The flexible Hf0.5Zr0.5O2 thin membranes with a thickness of ∼8 nm exhibit a high remanent polarization of ∼16 μC/cm2, which possess very robust polarization switching endurance (>1010 cycles, two orders of magnitude better than reported flexible HfO2-based films) and superior retention ability (expected >10 years). In particular, stable ferroelectric polarization as well as excellent endurance and retention performance show negligible degradations under 6 mm radius bending conditions or after 104 bending cycles with a 6 mm bending radius. These results mark a crucial step in the development of flexible hafnium oxide-based ferroelectric memories for wearable electronic devices.

A multimode‐fused sensory memory system based on a robust self‐assembly nanoscaffolded BaTiO3:Eu2O3 memristor

AbstractBiologically inspired neuromorphic sensory memory systems based on memristor have received a lot of attention in the booming artificial intelligence industry due to significant potential to effectively process multi‐sensory signals from complex external environments. However, many memristors have significant switching parameters disperse, which is a great challenge for using memristors in bionic neuromorphic sensory memory systems. Herein, a stable ferroelectric memristor based on the Pd/BaTiO3:Eu2O3/La0.67Sr0.33MnO3 grown on Silicon structure with SrTiO3 as buffer layer is presented. The device possesses low coercive field voltage (−1.3–2.1 V) and robust endurance characteristic (~1010 cycles) through optimizing the growth temperature. More importantly, an ultra‐stable artificial multimodal sensory memory system with visual and tactile functions was reported for the first time by combining a pressure sensor, a photosensitive sensor, and a robotic arm. Utilizing the above system, the sensitivity value of the system is expressed by the conductance of the memristor to realize the gradual change of external stimulus, and multi signals inputs at the same time to this system have faithfully achieved sensory adaptation to multimodal sensors. This work paves the way for future development of memristor‐based perception systems in efficient multisensory neural robots.image

Ultra-low operation current and abnormal bipolar switching phenomena of hydrogen-passivated HfO2 memristive devices for low power artificial neural network applications

We successfully demonstrated a hydrogen (H2)-passivated HfO2-based memristive device that operates with a low current that is below sub-nA in this paper. Gradual resistance changes are achieved with the diversification of the sweeping voltage. The H2-passivated HfO2-based memristive device shows an improvement of the device's performance of low power consumption with sub-nA, data retention for 104 s, and robust endurance of 106 repetitive cycles. The Spike Timing Dependent Plasticity (STDP) and the pattern recognition via MNIST are employed to assess the artificial neural network characteristics of the proposed device. A symmetrical curve on STDP is observed for an H2-passivated HfO2-based memristive device, which indicates that it can facilitate in order to mimic a human brain. The high accuracy of 91.12% and a clearer pattern recognition are obtained on an H2-passivated memristive device. Therefore, we believe that the H2-passivated HfO2-based memristive device opens up a new path in order to mimic the human brain with low power.