Ambipolar conduction in gated tungsten disulphide nanotube.

Devices based on transition metal dichalcogenide nanotubes hold great potential for electronic and optoelectronic applications. Herein, the electrical transport and photoresponse characteristics of a back-gate device with a channel made of a single tungsten disulfide (WS) nanotube are investigated as functions of electric stress, ambient pressure, and illumination. As a transistor, the device exhibits p-type conduction, which can be transformed into ambipolar conduction at a high drain-source voltage.

Current Advances in Nanoelectronics, Nanosensors, and Devices.

This Special Issue on "Current Advances in Nanoelectronics, Nanosensors, and Devices" collects cutting-edge research and comprehensive reviews in the rapidly evolving field of nanotechnology. This collection aims to highlight key breakthroughs in nanostructures, 2D materials, and their applications in nanoelectronics, nanosensors, and emerging device technologies.

The Superconducting Mechanism in BiS-Based Superconductors: A Comprehensive Review with Focus on Point-Contact Spectroscopy.

The family of BiS-based superconductors has attracted considerable attention since their discovery in 2012 due to the unique structural and electronic properties of these materials. Several experimental and theoretical studies have been performed to explore the basic properties and the underlying mechanism for superconductivity. In this review, we discuss the current understanding of pairing symmetry in BiS-based superconductors and particularly the role of point-contact spectroscopy in unravelling the mechanism underlying the superconducting state.

Field enhancement induced by surface defects in two-dimensional ReSe field emitters.

The field emission properties of rhenium diselenide (ReSe) nanosheets on Si/SiO substrates, obtained through mechanical exfoliation, have been investigated. The n-type conduction was confirmed by using nano-manipulated tungsten probes inside a scanning electrode microscope to directly contact the ReSe flake in back-gated field effect transistor configuration, avoiding any lithographic process. By performing a finite element electrostatic simulation of the electric field, it is demonstrated that the use of a tungsten probe as anode, at a controlled distance from the ReSe emitter surface, allows the collection of emitted electrons from a reduced area that furtherly decreases by reducing the tip-sample distance, allowing a local characterization of the field emission properties.

WS Nanotube Transistor for Photodetection and Optoelectronic Memory Applications.

Nanotube and nanowire transistors hold great promises for future electronic and optoelectronic devices owing to their downscaling possibilities. In this work, a single multi-walled tungsten disulfide (WS) nanotube is utilized as the channel of a back-gated field-effect transistor. The device exhibits a p-type behavior in ambient conditions, with a hole mobility µ ≈  1.

Multilayer WS for low-power visible and near-infrared phototransistors.

Mechanically exfoliated multilayer WS flakes are used as the channel of field effect transistors for low-power photodetection in the visible and near-infrared (NIR) spectral range. The electrical characterization as a function of the temperature reveals devices with n-type conduction and slightly different Schottky barriers at the drain and source contacts. The WS phototransistors can be operated in self-powered mode, yielding both a current and a voltage when exposed to light.

Memory effect and coexistence of negative and positive photoconductivity in black phosphorus field effect transistor for neuromorphic vision sensors.

Black phosphorus (BP) field-effect transistors with ultrathin channels exhibit unipolar p-type electrical conduction over a wide range of temperatures and pressures. Herein, we study a device that exhibits mobility up to 100 cm V s and a memory window up to 1.3 μA.

Subthreshold Current Suppression in ReS Nanosheet-Based Field-Effect Transistors at High Temperatures.

Two-dimensional rhenium disulfide (ReS), a member of the transition-metal dichalcogenide family, has received significant attention due to its potential applications in field-effect transistors (FETs), photodetectors, and memories. In this work, we investigate the suppression of the subthreshold current during the forward voltage gate sweep, leading to an inversion of the hysteresis in the transfer characteristics of ReS nanosheet-based FETs from clockwise to anticlockwise. We explore the impact of temperature, sweeping gate voltage, and pressure on this behavior.

Temperature-Dependent Conduction and Photoresponse in Few-Layer ReS.

The electrical behavior and the photoresponse of rhenium disulfide field-effect transistors (FETs) have been widely studied; however, only a few works have investigated the photocurrent as a function of temperature. In this paper, we perform the electrical characterization of few-layer ReS-based FETs with Cr-Au contacts over a wide temperature range. We exploit the temperature-dependent transfer and output characteristics to estimate the effective Schottky barrier at the Cr-Au/ReS interface and to investigate the temperature behavior of parameters, such as the threshold voltage, carrier concentration, mobility, and subthreshold swing.

Superconducting- and Graphene-Based Devices.

This Special Issue has been organized to collect new or improved ideas regarding the exploitation of superconducting materials, as well as graphene, aiming to develop innovative devices [...

Electric Transport in Few-Layer ReSe Transistors Modulated by Air Pressure and Light.

We report the fabrication and optoelectronic characterization of field-effect transistors (FETs) based on few-layer ReSe. The devices show n-type conduction due to the Cr contacts that form low Schottky barriers with the ReSe nanosheet. We show that the optoelectronic performance of these FETs is strongly affected by air pressure, and it undergoes a dramatic increase in conductivity when the pressure is lowered below the atmospheric one.

Transport and Point Contact Measurements on PrCePtGe Superconducting Polycrystals.

We performed a detailed investigation of the superconducting properties of polycrystalline PrCePtGe pellets. We report the effect of Ce substitution, for x = 0.07, on magnetic field phase diagram H-T.

Field emission from AlGaN nanowires with low turn-on field.

We fabricate AlGaN nanowires by molecular beam epitaxy and we investigate their field emission properties by means of an experimental setup using nano-manipulated tungsten tips as electrodes, inside a scanning electron microscope. The tip-shaped anode gives access to local properties, and allows collecting electrons emitted from areas as small as 1 µm. The field emission characteristics are analysed in the framework of Fowler-Nordheim theory and we find a field enhancement factor as high as β = 556 and a minimum turn-on field [Formula: see text] = 17 V µm for a cathode-anode separation distance [Formula: see text] = 500 nm.

Electron Irradiation of Metal Contacts in Monolayer MoS Field-Effect Transistors.

Metal contacts play a fundamental role in nanoscale devices. In this work, Schottky metal contacts in monolayer molybdenum disulfide (MoS) field-effect transistors are investigated under electron beam irradiation. It is shown that the exposure of Ti/Au source/drain electrodes to an electron beam reduces the contact resistance and improves the transistor performance.

Electron irradiation of multilayer [Formula: see text] field effect transistors.

Palladium diselenide ([Formula: see text]) is a recently isolated layered material that has attracted a lot of interest for its pentagonal structure, air stability and electrical properties that are largely tunable by the number of layers. In this work, multilayer [Formula: see text] is used as the channel of back-gate field-effect transistors, which are studied under repeated electron irradiations. Source-drain [Formula: see text] electrodes enable contacts with resistance below [Formula: see text].

Nanotip Contacts for Electric Transport and Field Emission Characterization of Ultrathin MoS Flakes.

We report a facile approach based on piezoelectric-driven nanotips inside a scanning electron microscope to contact and electrically characterize ultrathin MoS2 (molybdenum disulfide) flakes on a SiO2/Si (silicon dioxide/silicon) substrate. We apply such a method to analyze the electric transport and field emission properties of chemical vapor deposition-synthesized monolayer MoS, used as the channel of back-gate field effect transistors. We study the effects of the gate-voltage range and sweeping time on the channel current and on its hysteretic behavior.

Bias Tunable Photocurrent in Metal-Insulator-Semiconductor Heterostructures with Photoresponse Enhanced by Carbon Nanotubes.

Metal-insulator-semiconductor-insulator-metal (MISIM) heterostructures, with rectifying current-voltage characteristics and photosensitivity in the visible and near-infrared spectra, are fabricated and studied. It is shown that the photocurrent can be enhanced by adding a multi-walled carbon nanotube film in the contact region to achieve a responsivity higher than 100   mA   W - 1 under incandescent light of 0.1   mW   cm - 2 .

Thermoresistive Properties of Graphite Platelet Films Supported by Different Substrates.

Large-area graphitic films, produced by an advantageous technique based on spraying a graphite lacquer on glass and low-density polyethylene (LDPE) substrates were studied for their thermoresistive applications. The spray technique uniformly covered the surface of the substrate by graphite platelet (GP) unities, which have a tendency to align parallel to the interfacial plane. Transmission electron microscopy analysis showed that the deposited films were composed of overlapped graphite platelets of different thickness, ranging from a few tens to hundreds of graphene layers, and Raman measurements provided evidence for a good graphitic quality of the material.

Field Emission Characterization of MoS Nanoflowers.

Nanostructured materials have wide potential applicability as field emitters due to their high aspect ratio. We hydrothermally synthesized MoS nanoflowers on copper foil and characterized their field emission properties, by applying a tip-anode configuration in which a tungsten tip with curvature radius down to 30-100 nm has been used as the anode to measure local properties from small areas down to 1-100 µm. We demonstrate that MoS nanoflowers can be competitive with other well-established field emitters.

Graphene Schottky Junction on Pillar Patterned Silicon Substrate.

A graphene/silicon junction with rectifying behaviour and remarkable photo-response was fabricated by transferring a graphene monolayer on a pillar-patterned Si substrate. The device forms a 0.11 eV Schottky barrier with 2.

A WSe vertical field emission transistor.

We report the first observation of a gate-controlled field emission current from a tungsten diselenide (WSe2) monolayer, synthesized by chemical-vapour deposition on a SiO2/Si substrate. Ni contacted WSe2 monolayer back-gated transistors, under high vacuum, exhibit n-type conduction and drain-bias dependent transfer characteristics, which are attributed to oxygen/water desorption and drain induced Schottky barrier lowering, respectively. The gate-tuned n-type conduction enables field emission, i.

Transport and Field Emission Properties of MoS₂ Bilayers.

We report the electrical characterization and field emission properties of MoS 2 bilayers deposited on a SiO 2 / Si substrate. Current-voltage characteristics are measured in the back-gate transistor configuration, with Ti contacts patterned by electron beam lithography. We confirm the n-type character of as-grown MoS 2 and we report normally-on field-effect transistors.

Graphene enhanced field emission from InP nanocrystals.

We report the observation of field emission (FE) from InP nanocrystals (NCs) epitaxially grown on an array of p-Si nanotips. We prove that FE can be enhanced by covering the InP NCs with graphene. The measurements are performed inside a scanning electron microscope chamber with a nano-controlled W-thread used as an anode.

Field Emission from Self-Catalyzed GaAs Nanowires.

We report observations of field emission from self-catalyzed GaAs nanowires grown on Si (111). The measurements were taken inside a scanning electron microscope chamber with a nano-controlled tungsten tip functioning as anode. Experimental data were analyzed in the framework of the Fowler-Nordheim theory.