ABSTRACT We present a synthetic procedure for large Ti 2 CT x MXene monolayers with the majority of flakes having sizes of 10–15 µm and the largest ones reaching 40 µm, which are used for device fabrication and electrical measurements on a single‐flake level. We demonstrate that if exposed to ambient conditions, Ti 2 CT x monolayers oxidize in an aqueous solution or on a substrate on a time scale of hours, but multilayer flakes are more resistant to environmental degradation. The partially oxidized monolayer Ti 2 CT x flakes exhibit low electrical conductivity and electron mobility, as well as the semiconducting‐like temperature dependence of resistance with d R /d T < 0. However, the more degradation‐resistant multilayer flakes show electrical conductivity of about 3700 S cm −1 and electron mobility of about 1.6 cm 2 V −1 s −1 , which are among the highest values reported for MXene materials, as well as the metallic temperature dependence of resistance with d R /d T > 0, which is expected for Ti 2 CT x with mixed surface terminations (T x = ─F, ─OH, = O) based on prior theoretical calculations. These results correlate with the electrical measurements of Ti 2 CT x films, which showed that the thicker films exhibit better environmental stability. The characteristics of multilayer flakes suggest high intrinsic electrical conductivity of Ti 2 CT x and justify its potential for electronic applications.

ABSTRACT This study examines gate‐length engineering in recessed‐gate enhancement‐mode β‐Ga 2 O 3 metal‐oxide‐semiconductor field effect transistors on c‐plane sapphire, with emphasis on extending the gate to fully cover the etched recess. All epitaxial layers were grown simultaneously, and devices were fabricated using the same process flow, with gate length as the only design variable. Devices with a 3 µm gate partially cover the recessed region, while those with a 5 µm gate span the entire recess. Electrical measurements show that full recess coverage removes ungated segments, improves electrostatic control, and lowers series resistance. A significant threshold voltage shift, from 7.7 V to 2.4 V, was observed as gate coverage increased from 3 to 5 µm, further validated through TCAD simulations. Consequently, the specific on‐resistance decreases from 1.85 to 1.04 kΩ.mm, and the drain current on/off ratio improves from 1.8 × 10 7 to 1.6 × 10 8 , with normally‐off operation maintained. Capacitance‐voltage analysis further reveals that the field‐effect mobility increases from 2.06 to 5.29 cm 2 /V·s, while the channel electron concentration decreases from 8.2 × 10 16 to 5.4 × 10 16 cm −3 . These results demonstrate that complete recess coverage is an effective approach to enhance device conduction and subthreshold behavior without altering the fabrication process.

ABSTRACT The growing challenge of electronic waste drives demand for sustainable, biocompatible technologies and accelerates interest in edible electronics, systems that are safe for ingestion, biodegradable, and environmentally benign. Yet, the absence of mechanically reliable, healthy, and fully edible substrates compatible with scalable fabrication remains a major bottleneck. Here, we present a mechanically stable, fully edible substrate fabricated from wheat bran and algae via compression moulding, whose surface is further modified with chitosan spray coating to enhance water resistance and provide a uniform, coating‐compatible interface for subsequent deposition of functional inks. The substrate exhibits an ultimate tensile strength of ∼2.44 MPa, providing a stable platform for device integration. Subsequently, we develop a food‐grade conductive ink based on activated carbon and gummy bear binder, enabling uniform spray‐coated films with sheet resistance (7.6 kΩ/sq at 10 layers ∼67 µm) and linear Ohmic I–V characteristics. Moreover, electrochemical impedance spectroscopy reveals near‐ideal capacitive behaviour, with phase angle measurements across the 10 3 –10 6 Hz frequency range and Nyquist plots confirming the suitability of the system for energy storage applications. This scalable approach establishes a versatile route toward fully edible electronic platforms, opening opportunities for safe, low‐cost devices in diagnostics, smart packaging, and sustainable IoT applications.

ABSTRACT Reversible weight tuning is critical for edge AI chips, enabling online learning and local inference. Conventionally, the transition from analog interfacial switching to abrupt filamentary switching in memristors is commonly considered irreversible, as high electric fields induce conductive filaments, locking devices in the filamentary state. Here, we report that TiN/HfO 2 /Pt memristors exhibit stable interfacial switching and achieve voltage‐driven, repeatable interfacial‐to‐filamentary‐to‐interfacial (I‐F‐I) transitions. Systematic electrical characterization demonstrates more than 10 stable I‐F‐I transition sequences, controllable I‐F‐I transition yield exceeding 40%, a preserved resistance window, and an ON/OFF ratio of about 30. High bias activates a fast digital filamentary mode, while low bias restores a linearly tunable analog interfacial mode. Two defect migration models—soft filament and Schottky emission—elucidate this phenomenon. This analog‐digital switching could in the future, enable single‐chip training and inference and support reconfigurable logic‐in‐memory architectures, advancing low‐power artificial neural networks as well as neuromorphic computing for edge AI applications.

Abstract Different from traditional ferroelectrics whose polarization stems from ionic displacements mediated by phonons, electronic ferroelectrics exhibit spontaneous polarization originating from polar electronic ordering. Such electronic mechanisms promise devices with ultrafast switching speeds, lower energy consumption, and enhanced resilience to fatigue and depolarization fields inherent in conventional ferroelectrics. While early candidates are restricted to rare oxides and organic charge‐transfer salts, emerging systems—particularly 2D van der Waals moiré heterostructures—have significantly broadened this materials landscape. This review comprehensively examines ferroelectrics governed by electronic mechanisms, categorizing them according to microscopic origins, including spin correlations, charge ordering, orbital interactions, charge‐transfer instabilities, and excitonic phenomena. Representative materials span multiferroics, molecular crystals, and engineered van der Waals architectures. Crucially, we evaluate whether their ferroelectricity qualifies as purely electronic —defined by the absence of ionic displacements during polarization reversal—synthesizing recent theoretical and experimental advances to establish a unified framework for this evolving paradigm.

ABSTRACT Achieving ultrahigh mobility in oxide semiconductors without sacrificing stability has remained a long‐standing challenge owing to their inherent disorder and the tradeoff between mobility and stability. In this study, we demonstrated for the first time that the completeness of atomic layer deposition (ALD) surface reactions is the key factor for the formation of well‐defined vertical heterostructures in amorphous InGaZnO (IGZO) thin films, which in turn trigger quantum confinement effects and 2Delectron gas (2DEG) like interfacial conduction. By comparing high‐reactivity oxygen plasma and low‐reactivity ozone as oxidants, we revealed that only plasma‐assisted ALD achieved complete surface reactions, yielding atomically ordered InO x– (Ga, Zn)O stacks with distinct interfaces. This engineered structure resulted in an exceptional field‐effect mobility (>87 cm 2 V −1 s −1 ) with positive threshold voltage (0.56 V), an apparent two‐step conduction signature, and superior stability of the positive/negative bias temperature stability of 0.35/−0.01 V. Temperature‐dependent transport from room to cryogenic temperature (83K) and high‐temperature annealing (600°C) further confirmed the correlation among reaction completeness, interface quality, and 2DEG‐like interfacial conduction. This study identifies a critical link between ALD surface chemistry and quantum transport in oxides and provides a novel and practical strategy to overcome the mobility–stability tradeoff in next‐generation oxide transistors.

ABSTRACT We investigate the influence of hydrostatic pressure on the physical properties of monolayer for spintronics applications. A phase transition from a ferromagnetic half‐metal to a ferromagnetic semiconductor is unveiled at 4.6 GPa, accompanied by a transition from a non‐polar (1T) to a polar (1H) structure. We demonstrate that hydrostatic pressure elevates the Curie temperature above room temperature (for example, 618 K at 5 GPa) and enhances the magnetic anisotropy energy (for example, 731 per formula unit at 5 GPa). A significant Dzyaloshinskii‐Moriya interaction is present in the 1H structure (due to the broken spatial inversion symmetry) and increases with the hydrostatic pressure. Together with the observation of in‐plane electric polarization (for example, 1.1 pCcm −1 at 5 GPa), this positions the 1H structure as a pioneer in the class of 2D materials. Exploiting the phase transition of monolayer , a single‐material magnetic tunnel junction is proposed and an outstanding tunneling magnetoresistance ratio is demonstrated.

ABSTRACT The emerging nitride ferroelectrics, such as Al 1‐x Sc x N promise to significantly advance our current information technology. In particular, two‐terminal memristive devices are ideal candidates for artificial intelligence accelerators and in‐memory computing due to their simplicity in design, non‐volatility and non‐destructive readout. The recent discovery of conductive domain walls in Al 1‐x Sc x N is a promising enabler for such technology, offering several benefits compared to barrier height modulation‐ or tunneling‐based devices. First, domain walls can be highly conductive and feature high read currents (required for aggressive lateral scaling and fast access times), also in non‐epitaxial films without being restricted to the technologically challenging ultrathin thickness regime (10 nm). Second, nitride ferroelectrics are fully compatible with silicon and GaN technology on which the ferroelectric domain wall memory (FeDMEM) can be integrated with logic circuitry. Third, excellent scalability and temperature resistance of ferroelectric Al 1‐x Sc x N were demonstrated, enabling scaled, low‐latency edge computing under extreme environmental conditions. In this study, a FeDMEM device consisting of a Pt/Al 0.72 Sc 0.28 N/Pt capacitor grown on Si substrates is electrically characterized in‐depth, revealing unique peculiarities in the memristive response. A read current density of 350 A/m 2 and an ON/OFF ratio of 20 is achieved, allowing for consistent storing of up to eight levels of information.

ABSTRACT Space‐time‐coding metasurfaces (STCMs) enable simultaneous controls of electromagnetic wave across multiple harmonics, but designing high‐performance coding sequences in real time remains challenging. Here, we propose an unsupervised physics‐informed deep learning framework that can generate optimal spatiotemporal coding patterns for arbitrary single‐ and dual‐beam requirements at each harmonic frequency. The proposed method features three key innovations: physics‐informed mechanisms to enable unsupervised learning without requiring paired training data, a dedicated strategy for multi‐bit metasurface configurations, and the Conflict Averse Gradient descent (CAGrad) method to coordinate the parameter optimization across harmonics in multi‐task learning. Experiments on a 2‐bit STCM demonstrate robust beamforming capabilities over five harmonics, achieving an average radiation difference of 1.55 dB and real‐time design <0.1s. This is a 4‐order‐of‐magnitude improvement in computational efficiency compared with the particle swarm optimization methods. This work establishes a real‐time and physics‐aware design paradigm for intelligent metasurfaces in the next‐generation wireless systems.

ABSTRACT 2D semiconducting H‐phase vanadium disulfide (VS 2 ) has attracted significant research interest due to its exceptional potential in electronics, optoelectronics, spintronics, and valleytronics. In this work, VS 2 thin films are synthesized via chemical vapor deposition for the application of photodetectors, revealing a tunable dual‐photoconductivity effect induced by CO 2 adsorption and light‐assisted desorption. CO 2 adsorption led to negative photoconductivity, achieving a remarkable responsivity of ∼2680 A/W and an ultra‐high external quantum efficiency of ∼1.3 × 10 6 %. In contrast, VS 2 photodetectors free from CO 2 adsorption exhibited stable positive photoconductivity, with a maximum responsivity and external quantum efficiency of ∼0.11 A/W and ∼30.47%, respectively. First‐principles calculations demonstrate that CO 2 exhibits superior adsorption and desorption capabilities on the VS 2 surface compared to other ambient gas molecules (e.g., N 2 , O 2 , and H 2 O). This work highlights the profound influence of gas adsorption on the photoconductivity behavior of VS 2 thin films, providing critical insights into their optoelectronic properties and enabling non‐destructive modulation for advanced device applications.