Janus Electronic Devices with Ultrathin High-κ Gate Dielectric Directly Integrated on 1T'-MoTe.

Integrating high-quality dielectrics with two-dimensional (2D) transition metal chalcogenides (TMDCs) is crucial for high-performance electronics. However, the lack of dangling bonds on 2D material surfaces complicates direct dielectric deposition. We propose using atomic layer deposition (ALD) to integrate ultrathin high-κ dielectric directly on 1T'-MoTe surfaces, facilitating the creation of high-performance back-gated field-effect transistors (FETs).

Fabrication of ZnO Nanowire Cold Cathode Flat-Panel X-ray Source with a Reflective Anode.

A novel reflective anode flat-panel X-ray source using ZnO nanowire cold cathode and a metal anode has been developed. Simulation analysis indicated that the reflective anode structure reduces electric field concentration compared to a transmission anode structure. The current-voltage characteristics, X-ray radiation dose rate, and stability of the fabricated device were thoroughly characterized.

Controlling Gold-Assisted Exfoliation of Large-Area MoS Monolayers with External Pressure.

Gold-assisted exfoliation can fabricate centimeter- or larger-sized monolayers of van der Waals (vdW) semiconductors, which is desirable for their applications in electronic and optoelectronic devices. However, there is still a lack of control over the exfoliation processes and a limited understanding of the atomic-scale mechanisms. Here, we tune the MoS-Au interface using controlled external pressure and reveal two atomic-scale prerequisites for successfully producing large-area monolayers of MoS.

One-Step Synthesis of Heterostructured Mo@MoO Nanosheets for High-Performance Supercapacitors with Long Cycling Life and High Rate Capability.

Supercapacitors have gained increased attention in recent years due to their significant role in energy storage devices; their impact largely depends on the electrode material. The diversity of energy storage mechanisms means that various electrode materials can provide unique benefits for specific applications, highlighting the growing trend towards nanocomposite electrodes. Typically, these nanocomposite electrodes combine pseudocapacitive materials with carbon-based materials to form heterogeneous structural composites, often requiring complex multi-step preparation processes.

Fluorescent, multifunctional anti-counterfeiting, fast response electrophoretic display based on TiO/CsPbBr composite particles.

Traditional optical anti-counterfeiting (AC) is achieved by static printed images, which makes them susceptible to lower levels of security and easier replication. Therefore, it is essential to develop AC device with dynamic modulation for higher security. Electrophoretic display (EPD) has the advantages of low power consumption, high ambient contrast ratio, and capability of showing dynamic images which is suitable for dynamic AC applications.

Characteristics of Carbon Nanotube Cold Cathode Triode Electron Gun Driven by MOSFET Working at Subthreshold Region.

The carbon nanotube cold cathode has important applications in the X-ray source, microwave tube, neutralizer, etc. In this study, the characteristics of carbon nanotube (CNT) electron gun in series with metal-oxide-semiconductor field-effect transistor (MOSFET) were studied. CNTs were prepared on a stainless steel substrate by chemical vapor deposition and assembled with a mesh gate to form an electron gun.

Dependence of Ultrafast Electron Emission Characteristics of Graphene Cold Cathode on Femtosecond Photoexcitation Polarization Angle.

Ultrafast electron pulses, generated through femtosecond photoexcitation in nanocathode materials, introduce high-frequency characteristics and ultrahigh temporal-spatial resolution to vacuum micro-nano electronic devices. To advance the development of ultrafast electron sources sensitive to polarized light, we propose an ultrafast pulsed electron source based on a vertical few-layer graphene cold cathode. This source exhibits selective electron emission properties for varying polarization angles, with high switching ratios of 277 (at 0°) and 235 (at 90°).

Field-Emission Energy Distribution of Carbon Nanotube Film and Single Tube under High Current.

A narrow energy distribution is a prominent characteristic of field-emission cold cathodes. When applied in a vacuum electronic device, the cold cathode is fabricated over a large area and works under a high current and current density. It is interesting to see the energy distribution of the field emitter under such a working situation.

AC Characteristics of van der Waals Bipolar Junction Transistors Using an MoS/WSe/MoS Heterostructure.

Two-dimensional layered materials, characterized by their atomically thin thicknesses and surfaces that are free of dangling bonds, hold great promise for fabricating ultrathin, lightweight, and flexible bipolar junction transistors (BJTs). In this paper, a van der Waals (vdW) BJT was fabricated by vertically stacking MoS, WSe, and MoS flakes in sequence. The AC characteristics of the vdW BJT were studied for the first time, in which a maximum common emitter voltage gain of around 3.

Effect of Crystallinity on the Field Emission Characteristics of Carbon Nanotube Grown on W-Co Bimetallic Catalyst.

Carbon nanotube (CNT) is an excellent field emission material. However, uniformity and stability are the key issues hampering its device application. In this work, a bimetallic W-Co alloy was adopted as the catalyst of CNT in chemical vapor deposition process.

Multi-grayscale driving system for passive-matrix alternating current electroluminescence display.

Alternating current electroluminescence (ACEL) has great potential in flexible displays, especially in textile displays. However, since ACEL needs high-frequency, high-voltage AC signal to drive, there remains no driving scheme for pixelated ACEL display to achieve multiple gray scales. In this work, a driving scheme based on full-bridge inverters is proposed for passive-matrix ACEL (PMACEL) display, which achieves multiple gray scales by changing the duty cycle of the square wave.

Realization of High Current Gain for Van der Waals MoS/WSe/MoS Bipolar Junction Transistor.

Two-dimensional (2D) materials have attracted great attention in the past few years and offer new opportunities for the development of high-performance and multifunctional bipolar junction transistors (BJTs). Here, a van der Waals BJT based on vertically stacked n-MoS/WSe/MoS was demonstrated. The electrical performance of the device was investigated under common-base and common-emitter configurations, which show relatively large current gains of α ≈ 0.

A Flexible and Wearable Photodetector Enabling Ultra-Broadband Imaging from Ultraviolet to Millimeter-Wave Regimes.

Flexible and miniaturized photodetectors, offering a fast response across the ultraviolet (UV) to millimeter (MM) wave spectrum, are crucial for applications like healthcare monitoring and wearable optoelectronics. Despite their potential, developing such photodetectors faces challenges due to the lack of suitable materials and operational mechanisms. Here, the study proposes a flexible photodetector composed of a monolayer graphene connected by two distinct metal electrodes.

Stretchable, Transparent, and Ultra-Broadband Terahertz Shielding Thin Films Based on Wrinkled MXene Architectures.

With the increasing demand for terahertz (THz) technology in security inspection, medical imaging, and flexible electronics, there is a significant need for stretchable and transparent THz electromagnetic interference (EMI) shielding materials. Existing EMI shielding materials, like opaque metals and carbon-based films, face challenges in achieving both high transparency and high shielding efficiency (SE). Here, a wrinkled structure strategy was proposed to construct ultra-thin, stretchable, and transparent terahertz shielding MXene films, which possesses both isotropous wrinkles (height about 50 nm) and periodic wrinkles (height about 500 nm).

Controlled Preparation of High Quality Bubble-Free and Uniform Conducting Interfaces of Vertical van der Waals Heterostructures of Arrays.

Sharp and clean interfaces of van der Waals (vdW) heterostructures are highly demanded in two-dimensional (2D) materials-based devices. However, current assembly methods usually cause interfacial bubbles and wrinkles, hindering carrier interlayer transport. The preparation of a large-scale vdW heterostructure with a bubble-free interface is still a challenge.

Plasma Treatment for Achieving Oxygen Substitution in Layered MoS and the Room-Temperature Mid-Infrared (10 μm) Photoresponse.

Highly sensitive photodetectors in the mid-infrared (MIR, 3-15 μm) are highly desired in a growing number of applications. However, only a handful of narrow-band-gap semiconductors are suitable for this purpose, most of which require cryogenic cooling to increase the signal-to-noise ratio. The realization of high-performance MIR photodetectors operating at room temperature remains a challenge.

A low-loss molybdenum plasmonic waveguide: perfect single-crystal preparation and subwavelength grating optimization.

Plasmonic waveguides have attracted tremendous interest due to efficiently confining photons on the subwavelength spatial scale to be beating the propagation diffraction limit. Transition metal molybdenum (Mo) exhibits outstanding properties in light trapping and electromagnetic field confining, making it potentially valuable in 1.55 μm plasmonic waveguide applications.

In-plane dipolar nano-antenna steers polariton waves at nanoscale.

Hyperbolic polaritons can be launched and guided into mirror-symmetric-broken trajectories using an in-plane dipolar nano-antenna, and this asymmetry can be configured by adjusting the polarization direction of the in-plane dipole moment.

High-Performance Planar Field-Emission Photodetector of Monolayer Tungsten Disulfide with Microtips.

Monolayer tungsten disulfide (ML WS ) is believed as an ideal photosensitive material due to its small direct bandgap, large exciton/trion binding energy, high carrier mobility, and considerable quantum conversion efficiency. Compared with other photosensitive devices, planar field emission (FE)-type photodetectors with a full-plane structure should simultaneously have rapider switching speed and lower power consumption. In this work, ML WS microtips are fabricated by electron beam lithography (EBL) way and used to construct a planar FE-type photodetector.

Néel-type optical target skyrmions inherited from evanescent electromagnetic fields with rotational symmetry.

Optical skyrmions have recently attracted growing interest due to their potential applications in deep-subwavelength imaging and nanometrology. While optical skyrmions have been successfully demonstrated using different field vectors, the study of their generation and control, as well as their general correlation with electromagnetic (EM) fields, is still in its infancy. Here, we theoretically propose that evanescent transverse-magnetic-polarized (TM-polarized) EM fields with rotational symmetry are actually Néel-type optical target skyrmions of the electric field vectors.

In-plane hyperbolic polariton tuners in terahertz and long-wave infrared regimes.

One of the main bottlenecks in the development of terahertz (THz) and long-wave infrared (LWIR) technologies is the limited intrinsic response of traditional materials. Hyperbolic phonon polaritons (HPhPs) of van der Waals semiconductors couple strongly with THz and LWIR radiation. However, the mismatch of photon - polariton momentum makes far-field excitation of HPhPs challenging.

A tunable photo-electric co-excited point electron source: low-intensity excitation emission and structure-modulated spectrum-selection.

The development of a point electron source requires an efficient excitation mode with low energy consumption, flexible tunability, and high performance. In particular for traditional electron emission cathode materials, it is necessary to expand the function of this aspect to meet application demands in many emerging fields. In this study, we propose a photo-electric co-excited scheme to drive a tungsten (W) needle nano-cold-cathode.

Aluminum Nitride Ultraviolet Light-Emitting Device Excited via Carbon Nanotube Field-Emission Electron Beam.

With the progress of wide bandgap semiconductors, compact solid-state light-emitting devices for the ultraviolet wavelength region are of considerable technological interest as alternatives to conventional ultraviolet lamps in recent years. Here, the potential of aluminum nitride (AlN) as an ultraviolet luminescent material was studied. An ultraviolet light-emitting device, equipped with a carbon nanotube (CNT) array as the field-emission excitation source and AlN thin film as cathodoluminescent material, was fabricated.

High Responsivity Vacuum Nano-Photodiode Using Single-Crystal CsPbBr Micro-Sheet.

Field electron emission vacuum photodiode is promising for converting free-space electromagnetic radiation into electronic signal within an ultrafast timescale due to the ballistic electron transport in its vacuum channel. However, the low photoelectric conversion efficiency still hinders the popularity of vacuum photodiode. Here, we report an on-chip integrated vacuum nano-photodiode constructed from a Si-tip anode and a single-crystal CsPbBr cathode with a nano-separation of ~30 nm.