Wenjuan Zhu

The increasing demand for data-centric and artificial intelligence workloads has intensified the need for device platforms that integrate logic, memory, and adaptive computing beyond conventional von Neumann architectures. Here, an aluminum scandium nitride (AlScN)-based nonvolatile four-mode reconfigurable field-effect transistor is demonstrated as a multifunctional device platform. By combining the large remanent polarization of AlScN with the ambipolar transport of the MoTe2 channel, the same transistor can be persistently programmed into logic nFET, logic pFET, memory-on, and memory-off states. These modes arise from polarization-controlled modulation of carrier injection and channel electrostatics, enabling a single device to function as a polarity-reconfigurable logic element, nonvolatile memory cell, and analog synaptic element. Programming is performed through voltage pulses applied to the source, drain, and back gate, while top-gate readout is decoupled from AlScN programming, enabling stable nonvolatile operation. Based on this device, a single-transistor ternary content-addressable memory cell concept and two-input reconfigurable multifunctional logic gates are demonstrated. The wide polarization-tunable memory window further supports multilevel cell memory and nearly linear long-term potentiation and depression for neuromorphic synaptic operation. These results establish ferroelectric AlScN as a robust platform for integrating reconfigurable logic, nonvolatile memory, associative search, and neuromorphic computing within a common device framework.

We demonstrate high-temperature operation of Al0.83In0.17N/GaN high-electron-mobility transistors (HEMTs) at 800 K (∼527 °C) enabled by a post-fabrication supercritical fluid (SCF) treatment. NH3-based SCF (NH3-SCF) and O2-based SCF (O2-SCF) processes are systematically compared, showing that O2-SCF provides more effective oxidative passivation for interface engineering under extreme-temperature conditions. The O2-SCF treatment suppresses off-state leakage current by more than five orders of magnitude at room temperature and over two orders at 800 K, while increasing on-current by 30%–40% and reducing on-resistance from 10 to 8 Ω mm. The O2-SCF devices exhibit a subthreshold swing of 64 mV/dec and an on/off current ratio of 1012 at room temperature, retaining 230 mV/dec and 104 at 800 K, among the best reported for III-nitride HEMTs operating above 500 °C. These results demonstrate that O2-SCF is an effective post-fabrication strategy for improving interface quality and mitigating performance degradation at elevated temperatures in Al0.83In0.17N/GaN HEMTs, with potential for electronics in harsh environments.

Nonvolatile flip-flops and latches have been proposed as key building blocks for improving the reliability and energy efficiency of computing systems operating under aggressive power gating and intermittent power availability. Ferroelectric field-effect transistors (FeFETs) based on van der Waals (vdW) heterostructures provide a promising approach for nonvolatile sequential logic by enabling direct integration of memory functionality into logic devices while minimizing interface-related degradation. In this work, CuInP₂S₆-based vdW FeFETs are fabricated in both metal-ferroelectric-metal-insulator-semiconductor and metal-ferroelectric-semiconductor configurations, exhibiting robust ferroelectric switching and stable nonvolatile behavior. Building on these devices, ferroelectric nonvolatile inverters are realized, followed by a nonvolatile ferroelectric latch that reliably restores its logic state after complete power loss. The proposed latch leverages ambipolar MoTe₂ channels to inherently drive the FeFET gate-source and gate-drain voltages to full rail-to-rail values (V_GS = V_GD = ±V_DD) in a state-dependent manner, thereby ensuring reliable polarization switching without auxiliary sensing circuitry or additional bias-management schemes. Owing to the clean vdW interfaces and intrinsic circuit operation, the latch restores its state upon power recovery using only simple control signals. These results demonstrate the strong performance of 2D vdW FeFETs and establish nonvolatile latch operation as a viable experimental platform for nonvolatile sequential logic and energy-efficient computing architectures.

This work presents a comprehensive benchmarking of ternary content-addressable memory (TCAM) implementations using timing-accurate SPICE simulations, systematically comparing conventional CMOS designs with emerging device technologies, including magnetic tunnel junctions (MTJs), ferroelectric tunnel junctions (FTJs), ferroelectric field-effect transistors (FeFETs), and two-dimensional reconfigurable field-effect transistors (2D RFETs). Key performance metrics, including search delay, search energy, static power, cell area, sense margin, power-supply sensitivity, and CMOS compatibility, are evaluated alongside technology-specific trade-offs that govern scalability and robustness. The results identify FeFET-based TCAMs as the most balanced and scalable solution, delivering substantial improvements in energy efficiency, search latency, and cell area relative to CMOS baselines. 2D RFET-based TCAMs exhibit advantages in search energy, static power, and footprint; however, these benefits are offset by excessive search latency and limited CMOS compatibility, primarily stemming from material quality and process integration challenges. MTJ- and FTJ-based resistive TCAMs offer moderate gains in area and delay while maintaining strong CMOS compatibility but suffer from prohibitively high search energy due to static power dissipation in sense amplifiers during search operations. This behavior exposes an inherent trade-off between energy efficiency and robustness in resistive TCAM architectures.

Breakthroughs in nanotechnology have enabled the large-scale fabrication of nanoparticles with varied compositions and structures. Yet, evaluating their electrical conductivities remains challenging due to high volume and individual variability. We report a rapid, non-contact, and parallel method to characterize longitudinal nanostructures, including insulators, semiconductors, and conducting metal oxides by using MoO3, MoS2/MoO2, and MoS2 nanoribbons, produced at different fabrication stages, as a model system. Leveraging our semi-quantitative model based on Maxwell–Wagner and electrical double-layer polarization, electric conductivities of various nanoparticles are determined from their distinct electro-rotation behaviors in water, spanning six orders of magnitude. The results agree well with standard four-probe measurements. The technique, measuring multiple nanoparticles at once, without the use of electrical contact, can be easily scaled up for parallel determination of particles' electric conductivities. These findings highlight a nondestructive, rapid, and simple characterization method promising to bring nanomaterials closer to practical applications in electronics, optics, sensing, catalysis, and robotics.

MoTe ₂ possesses two polymorphs: semiconducting (2H) and semi‐metallic (1T') phases, separated by a small energy barrier. The 1T' phase of MoTe ₂ provides an excellent platform for forming low‐resistance contacts with the 2H phase, where the low density of states in the semimetal suppresses metal‐induced gap states (MIGS) and reduces Fermi‐level pinning. However, existing fabrication methods encounter significant challenges in location control, contact quality, and device scaling. In this work, a new method is developed to synthesize 1T'‐2H heterophase structures using chemical vapor deposition (CVD). By depositing pre‐patterned molybdenum, seamless in‐plane 1T'‐2H MoTe ₂ heterophase junctions are synthesized in a single‐step process, achieving precise control over the location of each phase and uniform MoTe ₂ coverage across centimeter‐scale surfaces. Field‐effect transistors incorporating 1T' MoTe ₂ contacts and 2H MoTe ₂ channels show p‐type dominant transfer characteristics and exceptionally low contact resistance. The unique attributes of these 1T' MoTe ₂ contacts, including pristine interfaces, reduced Schottky barrier heights, and seamless edge contacts, combined with the pronounced ambipolarity of the grown 2H MoTe ₂ , demonstrate the commercial viability of this process for 2D transistors, addressing the long‐standing challenge of contact resistance in 2D transistor technology.

Van der Waals (vdW) magnetic materials have attracted considerable attention for use in spintronic devices such as those controlled by spin-orbit torque (SOT). Such SOT-driven devices are typically fabricated by bringing a vdW magnet in proximity to a spin-charge conversion layer to achieve current-driven magnetization switching. Here, we show that such structures fabricated with iron germanium telluride (FGT) and platinum can exhibit emergent magnetic properties, which we attribute to magnetic proximity effects at the FGT/Pt interface. These changes manifest as increased perpendicular magnetic anisotropy and the emergence of additional magnetization reversal steps as probed by magneto-transport, with the most significant changes appearing in thinner flakes. The behavior was found to be robust and consistently appeared in samples made with crystals from different vendors. Our results demonstrate the potential for engineering vdW spintronic systems through magnetic proximity effects.

The scalable synthesis of materials with strong spin orbit coupling (SOC) is crucial for the development of spintronic and magnetic devices. Here, wafer-scale growth of 1T' MoTe₂ using metal-organic chemical vapor deposition (MOCVD) at low temperatures (400 °C) is demonstrated. The synthesized films exhibit uniform coverage across the entire substrate, as well as accurate stoichiometry. This low-temperature synthesis is compatible with silicon back-end-of-line (BEOL) processes, enabling in-memory and in-sensor computing for data-intensive applications. Furthermore, it was found that the grown 1T' MoTe₂ exhibits strong spin-orbit coupling, as revealed by the spin torque ferromagnetic resonance (ST-FMR) measurements conducted on a 1T' MoTe₂/permalloy bilayer. These measurements indicate significant damping-like torques in the wafer-scale 1T' MoTe₂ film and indicate high spin-charge conversion efficiency. The BEOL-compatible process and potent spin orbit torque demonstrate the promise of MOCVD-grown MoTe₂ in advanced device applications.

Emerging applications in data-intensive computing and circuit security demand logic circuits with high functional density, reconfigurability, and energy efficiency. Here, we demonstrate nonvolatile reconfigurable four-mode field-effect transistors (NVR4M-FETs) based on two-dimensional (2D) MoTe₂ and CuInP₂S₆ (CIPS), offering both polarity switching and threshold voltage modulation. The device exploits the ferroelectric polarization of CIPS at the source/drain regions to achieve dynamic control over the transistor polarity, enabling transitions between n-type and p-type states through polarization-induced local electrostatic doping. Additionally, multilayer graphene floating gates are incorporated to modulate the threshold voltage, yielding four distinct nonvolatile operating modes: n-type logic, p-type logic, always-on memory, and always-off memory. Leveraging the four-mode property, the NVR4M-FET can function as a one-transistor-per-bit ternary content-addressable memory (TCAM). In addition, we demonstrate the construction of transformable logic gates with 14 distinct logic functions using two NVR4M-FETs and a reconfigurable half a dder/subtractor using three NVR4M-FETs integrated with load resistors. Furthermore, we show that a 2-input look-up table can be achieved with eight NVR4M-FETs compared to 12 transistors using reconfigurable transistors, highlighting the potential of NVR4M-FETs for high-density logic circuits. These results underscore the potential of NVR4M-FETs as essential building blocks for energy-efficient, in-memory computing, and secure hardware applications.

Two-dimensional (2D) ferroelectric and magnetic van der Waals materials are emerging platforms for the discovery of novel cooperative quantum phenomena and development of energy-efficient logic and memory applications as well as neuromorphic and topological computing. This review presents a comprehensive survey of the rapidly growing 2D ferroic family from the synthesis perspective, including brief introductions to the top-down and bottom-up approaches for fabricating 2D ferroic flakes, thin films, and heterostructures as well as the important characterization techniques for assessing the sample properties. We also discuss the key challenges and future directions in the field, including scalable growth, property control, sample stability, and integration with other functional materials.