Tungsten diselenide (WSe2) is an important p-type two-dimensional (2D) semiconductor. However, a route to synthesize its monolayer films that simultaneously exhibit spatial uniformity, high crystalline quality, and full coverage remains elusive. Here, we demonstrate the growth of centimeter-scale uniform WSe2 monolayer films via a confined-space chemical vapor deposition method. Monolayer WSe2 films can be efficiently synthesized with minimal precursor consumption within 5 min. Crystalline structure analysis and spectroscopy measurements, together with the statistically analyzed transfer curves of an array of 25 transistors, confirm the good uniformity of the WSe2 film. This approach provides a scalable route to produce large-scale, homogeneous WSe2 films, which are crucial for electronic and integrated-circuit applications based on 2D semiconductors.

Passive rectifiers in radio frequency (RF) energy-harvesting applications require viable zero-bias responsivities to achieve significant RF-to-DC conversion efficiencies. While conventional metal-insulator-metal (MIM) diodes have been widely studied for high-frequency rectification, they often exhibit suboptimal zero-bias performance. Here, we demonstrate enhanced performance by modifying three key features of MIM diodes. We fabricated diodes with a second insulating layer, used graphene as one of the contacts, and formed a one-dimensional (1D) junction along the edge of graphene. The resulting 1D metal-double-insulator-graphene (MIIG) diode with TiO2 and Ta2O5 insulators shows excellent zero-bias responsivity of up to 9.7 A/W. Our model indicates that this is due to a mix of thermionic emission at the 1D junction, modulation of the graphene work function toward a lower transport barrier, and trap-assisted transport through Ta2O5. These results are essential for the development of high-efficiency rectennas for RF energy-harvesting applications.

While significant progress has been made in the fabrication of n-type contacts for two-dimensional field-effect transistors (2D FETs), the development of high-performance p-type counterparts using compatible techniques remains insufficient to realize competitive complementary circuits. Here, we demonstrate the growth of metallic-phase tellurium (m-Te) on MoTe2 via evaporation as an efficient p-type contact. The atomic arrangement at the Te/MoTe2 interface stabilizes m-Te under ambient conditions, forming an atomically sharp van der Waals gap with optimal band alignment and suppressed metal-induced gap states. Combined with hole doping and tellurium vacancies compensation, the interface enables barrier-free hole injection. Bilayer MoTe2 FETs employing m-Te contacts achieve a contact resistance as low as 1.6 kΩ μm, an on-state current up to 124 μA μm-1, and a maximum on/off ratio of 107, which are among the best values obtained for p-type 2D FETs. Our work unveils metallic-phase chalcogen as a promising approach for contact optimization.

A free-standing Ni3S2/Co9S8 composite with nanosheet-wrapped irregular structures is fabricated on nickel foam (NF) framework. Compared with pristine Ni3S2, the specific capacitance of Ni3S2/Co9S8 increases to 2.62 F cm−2 from 1.99 F cm−2, confirming a superior electrochemical activity of the composite. To further enhance the electrochemical performance and reveal the electrochemical activation behavior of the Ni3S2/Co9S8 composite, cyclic voltammetry (CV) activation strategy is employed by inducing the reconstruction of electrode materials in KOH solution. The CV activation triggers the dissolution of sulfur species and the formation of amorphous Ni/Co (oxy)hydroxides. The activated product achieves its maximum areal capacitance of 4.30 F cm−2 at 1 A g−1 after 200 cycles, resulting in a well-defined spherical structure consisted of interconnected ultrathin nanosheets. The capacitance enhancement can be ascribed to hierarchical spherical structure and the optimized composition, which provide abundant active sites and facilitate ion diffusion and charge transfer. When configured as an asymmetric supercapacitor, the device comprising the Ni3S2/Co9S8 composite and activated carbon exhibits a specific capacitance of 175.6 F g−1, and the highest energy density reaches 62.44 Wh kg−1. The Ni3S2/Co9S8 composite shows significant potential as a high-performance electrode material for advanced supercapacitor applications.

Ubiquitous electromagnetic radiation from wireless communication networks is an untapped energy source for low-power devices. Passive rectennas (a combination of a rectifier and an antenna) can harvest this energy to power devices and systems, such as autonomous sensors. Rectennas based on conventional rectifiers, however, lack the frequency response and zero-bias performance required to extend passive energy harvesting into the terahertz (THz) domain, which is crucial for Internet of Things (IoT) applications in the 6G era. In contrast, rectennas based on geometric rectifiers are ultrafast detectors that can operate without an external bias, making them ideally suited for zero-bias THz detection and energy harvesting. Geometric rectifiers require largely scatter-free, quasi-ballistic charge transport, which is typically achieved only in high-purity materials, which – as in the case of mechanically exfoliated graphene – may not be suitable for wafer-scale fabrication. In this work, we used commercially available graphene grown by chemical vapor deposition (CVD) to fabricate geometric rectennas and demonstrate operation up to 0.68 THz at zero bias. We employed a parallel arrangement of multiple rectifiers to increase the coupling efficiency between the rectifiers and the antennas, and thus the overall rectenna responsivity. Our results are a critical step towards large-scale fabrication of efficient geometric rectennas and enabling THz energy harvesting for low-power IoT devices.

Reconfigurable photodetectors featuring stable, high-speed, and nonvolatilely programmable photoresponse states are essential for in-sensor computing, yet their realization remains a significant challenge. Here, we report two-dimensional ambipolar floating-gate optoelectronic memories (2D AFGOMs) to address this limitation. By introducing an ambipolar channel, more balanced electron–hole transport is expected to facilitate carrier recombination after light removal, which is consistent with the observed fast and reversible optical modulation. Combined with the high interfacial barriers, the nonvolatilely programmed dark states remain nearly unchanged under repeated optical stimulation. As a result, the 2D AFGOMs exhibit 84 distinguishable photoresponse states (>6 bits) under 473 nm illumination, microsecond switching speeds (tr = 576 μs, td = 648 μs), and robust long-term dynamic stability (>104 s). This work provides a promising device platform for future neuromorphic vision-sensor research.

Abstract Anisotropic materials provide an ideal platform for on-chip polarimetric detection with immense potential in machine vision, bioimaging, and quantum computing. However, their polarization discrimination capability is often limited by the lack of an internal gain mechanism and the challenge of simultaneously detecting both linear and circular polarizations. To address this, we present a polarimetric photodetector with effective discrimination by designing an internal gain mechanism into a highly aligned tellurium (Te) nanowire film. This is achieved by leveraging the intrinsic photovoltaic effect along the crystallographic b axis, perpendicular to the helical chain direction (c axis). As a result, the two-terminal device along the b-axis exhibits dual-mode polarization discrimination capabilities, characterized by a linear polarization extinction ratio of 3.58 and a circular polarization asymmetry factor (|g|) of 0.65 in a single detector. Furthermore, we demonstrate a proof-of-concept polarization-encoded communication system that successfully decodes binary data encoded in both linear and circular polarization states, paving the way for advanced fully integrated optical sensing systems.

This work presents a $K_{a}$ -band thin-film compact differential analog phase-shifter implemented in a custom graphene monolithic microwave integrated circuit (MMIC) technology. The design exploits a distributed-type configuration utilizing graphene diodes as shunt tuning loads. The prototype is realized on an $8.1~\mu $ m-thick flexible polyimide (PI) substrate, and its core occupies less than 0.18 mm2 of chip area. The evaluation of the fabricated circuit reveals an average $S_{21}$ measurement of −3.2 dB in the frequency band of 20–30 GHz with a tunable phase difference ( $\Delta \Phi $ ) exceeding 90°. The introduced thin-film phase shifter promotes the realization of compact flexible and cost-effective solutions for next-generation high-frequency systems.

The commercialization of nanoscale Si and SiOx anodes faces challenges like substantial volume expansion, extensive interfacial side reactions, and low initial Coulombic efficiency (ICE). Recently, SiC anodes produced through chemical vapor deposition (CVD) by co-pyrolyzing silane and hydrocarbon gases on carbon scaffolds have attracted considerable attention from both academia and industry. The porous structure of carbon matrix facilitates the in-situ growth of Si particles, enhancing electrical conductivity and mechanical strength. This innovative design endows SiC anodes with high ICE, large reversible capacity, minimal volume expansion, and stable cycling performance. However, comprehensive research on these CVD-derived anodes is still lacking, particularly regarding the structural-property-performance relationships. This review aims to highlight recent developments by focusing on addressing the large volume expansion and severe side reactions during the lithiation process. Special attention is paid to the carbon matrix that buffers the volume expansion, including graphite, carbon nanotubes, and porous carbons with diverse pore size distributions and volumes. Factors affecting Si deposition particle size and morphology, such as deposition model, precursor selection, temperature, atmosphere, and kinetics, are also discussed. Additionally, the review summarizes the use of carbon films on Si particles that overcomes the low ICE, considering aspects like layer thickness, hydrocarbon gas sources and temperatures. Finally, effective strategies are proposed to promote the industrial adoption of SiC anodes.

Elemental tellurium (Te), with chiral atom chains held together by van der Waals (vdW) force, has recently gained significant attention due to its intriguing physical properties. However, the controlled synthesis of its vdW heterostructures remains challenging. Here, we synthesize uniaxially oriented Te/SexTe1-x vdW heterojunction nanowire (vdWHN) arrays with tunable composition (x = 0-0.45) using molecular beam epitaxy. By employing a molecular engineering strategy, we first obtained well-aligned Te nanowire nuclei, which then served as the basis for the growth of Te/SexTe1-x vdWHNs. Compositional and structural characterizations confirm the epitaxial relationship between Te and SexTe1-x and reveal atomically sharp heterointerfaces without observable defects. Building on this, we demonstrate the synthesis of bi-periodic Te/SexTe1-x vdWHNs. Furthermore, periodic stripes are observed on the nanowires, which are attributed to the combined effect of moir & eacute; patterns and interfacial lattice mismatch between Te and SexTe1-x. Field-effect transistors based on four-period Te/SexTe1-x vdWHNs demonstrate an on/off current ratio of 5 & times; 10(4) at 160 K. This study expands the controlled synthesis of vdW heterostructures and provides a foundation for the application of Te-based one-dimensional layered materials.

Recently, two-dimensional materials have emerged as promising candidates for next-generation memristive devices. In this work, atomic layer deposited 2D tungsten disulfide (WS2) was employed as the resistive switching medium for wafer-scale memristors. The memristors demonstrated stable current-voltage cycling endurance over 103 cycles and robust data retention exceeding 105 s. Furthermore, resistive switching with a set time as low as tens of nanoseconds was observed under pulsed voltage stress. By varying pulse parameters, we could also achieve short-term to long-term plasticity transition, highlighting their potential for artificial synaptic applications.

Low-dimensional materials are expected to play critical roles in next-generation electronic and optoelectronic devices, yet their controlled synthesis remains challenging. This is particularly true for emerging materials with interesting properties such as tellurium. Here we present a molecular engineering approach to synthesize wafer-scale, uniaxially oriented Te nanowire thin films with excellent controllability and uniformity. We show that molecules with an anchor-rope structure can facilitate the oriented growth of Te nanowires on m-plane sapphire. The resulting Te nanowires are well arranged, with 99.7 Using a molecular engineering approach, wafer-scale uniaxially oriented Te nanowire thin films are synthesized with excellent controllability and uniformity. The anchor-rope structural molecules form a periodic self-assembled supramolecular membrane, which facilitates the adsorption and well-arranged growth of Te nanowires on grooved sapphire.

A novel method has been developed for the deposition of high-kappa dielectrics on graphene, which uses a nonstoichiometric aluminum oxide (AlOX) protective layer. This approach employs mild plasma conditions to directly grow a thin AlOX layer on graphene, followed by the deposition of aluminum oxide (Al2O3) via plasma-enhanced atomic layer deposition (PEALD) without breaking the vacuum. A sub-3 nm AlOX layer provides effective protection for graphene and facilitates the formation of functional groups, thereby enabling the deposition of high-quality dielectrics without damaging the graphene. Top-gated graphene field-effect transistor (GFET) devices fabricated via this method demonstrated an electric field strength above 11 MV/cm and an equivalent oxide thickness (EOT) of less than 5 nm on a wafer scale. This deposition technique addresses a significant challenge in transitioning next-generation graphene-based electronics from the laboratory to industrial production.

Realizing low dark current density (Jd) while maintaining high photoresponse is crucial yet challenging for organic photodetectors (OPDs). In this work, two nonplanar small molecule electron acceptors, BTTPCN-F and BTTPCN-Cl, were developed. The OPDs based on them achieved ultralow Jd down to 2.95 × 10-13 A cm-2 and exceptionally high shot noise-limited detectivity (Dsh*) up to 1.12 × 1015 Jones, which are the lowest Jd and highest Dsh* reported for self-powered OPDs to date. The ultralow Jd is attributed to the high reorganization energy and small intermolecular electronic coupling in these nonplanar molecules. On the other hand, their large molecular dipole moment and high dielectric constant contribute to low exciton binding energy, leading to high photoresponse. Consequently, they can work as effective dark current suppressors for achieving high-performance binary or ternary OPDs. A dynamic gesture recognition system based on BTTPCN-Cl OPD was developed, which can accurately identify the gesture input. This work unveils the great potential of high dielectric constant nonplanar organic semiconductors for photodetection.

Floating-gate memories (FGMs) show great promise for neuromorphic computing in efficient data-centric applications. However, their limited single-device state capacity remains insufficient for highly integrated precision computing. Here, we demonstrate 11-bit two-dimensional (2D) MoS2 FGMs by contacting the 2D channels with bismuth electrodes, enabling 100 μA on-state current with 108 on/off ratio and reducing the current noise by 3 times (approaching the equipment limits) due to the Schottky barrier-free interfaces. Moreover, we employed a dual-pulse state editing scheme enhancing the stability of our FGMs. The devices show as high as 2,249 distinct conductance levels (>11-bit) while maintaining 230 ns operation speed, >104 s retention, and >105 cycle endurance. Furthermore, the gate-injection operation prevents the influence from generated defects during cycling, maintaining low noise even after 105 cycles and at 85 °C. Theoretical analysis reveals interfacial defects as the primary state-number limitation, suggesting 17-bit capacity is achievable through further trap density reduction. This work establishes 2D FGMs as promising candidates for high-bit-density, low-power neuromorphic hardware.

Silver phenylselenolate (AgSePh), known as mithrene, is a 2D metal-organic chalcogenolates (MOC) semiconductor with a wide direct bandgap, narrow blue emission, and in-plane anisotropy. However, its application in next-generation optoelectronics is limited by crystal size and orientation, as well as challenges in large-area growth. Here, a controlled tarnishing step is introduced on the silver surface prior to the solid-vapor-phase chemical transformation into AgSePh thin films. Mithrene thin films are prepared through thermally assisted conversion (TAC) at 100 degrees C, incorporating a water (H2O) vapor pulse treatment and propylamine (PrNH2) as an organic ligand. The AgSePh thin films are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and grazing incidence wide-angle X-ray scattering (GIWAXS). The pre-tarnishing process, combined with organic ligand, results in large crystals exceeding 1 mu m and improves homogeneous in-plane orientation, while also enabling the selective, wafer-scale synthesis of mithrene on 100 mm wafers. Furthermore, the films are integrated on planar graphene field-effect phototransistors (GFETs) and demonstrated photoresponsivity beyond 100 A W-1 at 450 nm, highlighting mithrene's potential for blue light-detection applications.

Surface plasmon polaritons (SPPs) at dielectric-metal interfaces are of significant interest in nanophotonic devices owing to their unique field localization behaviors. Low-dimensional metal structures like metal nanowires generate strong SPP modes, yet dynamic SPP modulation, particularly in the mid-infrared (IR) range, is still underdeveloped, hindering progress in reconfigurable SPP-based devices. Here, we demonstrate active control of mid-IR SPPs in silver nanowires (AgNWs) through electric field gating, taking advantage of a graphene monolayer substrate and its gate-tunable dielectric properties in the mid-IR range. Through IR near-field nanoimaging and numerical simulations, we explore the resulting range of the spectral tuning behavior of the AgNW SPP response. Furthermore, we identify a new gate-dependent decay channel in which SPPs in AgNWs directly dissipate into graphene SPPs. Our findings highlight the potential for utilizing the electrical characteristics of graphene for manipulating SPPs in metal nanowires, paving the way for the development of advanced nanophotonic devices.

Neuromorphic devices are revolutionizing the field of artificial intelligence (AI) by emulating the neural structure and computational efficiency of the human brain. These devices offer a new computing paradigm that integrates processing and memory, sidestepping the constraints of traditional von Neumann architecture. With capabilities like synaptic plasticity and energy efficiency, neuromorphic devices hold the promise of transforming AI systems into more powerful, adaptive, and efficient platforms. This review focuses on the advanced materials and their applications in neuromorphic devices, such as memristors, ferroelectrics, phase change materials and ionic conductor are at the forefront, enabling the simulation of synaptic weights and the potential for hardware-implemented neural networks. Despite challenges in device uniformity and system-level integration, continuous research and development are pushing the boundaries, aiming to fully realize the potential of neuromorphic computing hardwares.

Two-dimensional material (2DM)-based field-effect transistors (FETs), such as molybdenum disulfide (MoS2)-FETs, have gained significant attention for their potential for ultrashort channels, thereby extending Moore's law. However, MoS2-FETs are prone to the formation of Schottky barriers at the metal-MoS2 interface, resulting in high contact resistance (Rc) and, consequently, reduced transistor currents in the ON-state. Our study explores the modification of MoS2 to induce the formation of conductive 1T-MoS2 at the metal-MoS2 interface via reverse sputtering. MoS2-FETs exposed to optimized reverse sputtering conditions in the contact area show Rc values reduced to less than 50% of their untreated counterparts. This reduction translates into improvements in other electrical characteristics, such as higher ON-state currents. Since reverse sputtering is a standard semiconductor process that enhances the electrical performance of MoS2-FETs, it has great potential for broader application scenarios in 2DM-based microelectronic devices and circuits.