Controlled Bipolar Doping of One-Dimensional van der Waals NbPdSe.

Tailoring the electrical properties of one-dimensional (1D) van der Waals (vdW) materials is desirable for their applications toward electronic devices by exploiting their unique characteristics. However, 1D vdW materials have not been extensively investigated for modulation of their electrical properties. Here we control doping levels and types of 1D vdW NbPdSe over a wide energy range by immersion in AuCl or β-nicotinamide adenine dinucleotide (NADH) solutions, respectively.

Novel High Current-Carrying Quasi-1D Material: Nb PdS.

A quasi-one-dimensional van der Waals metallic nanowire Nb PdS is synthesized, and its electrical characteristics are analyzed. The chemical vapor transport method is applied to produce centimeter-scale Nb PdS crystals with needle-like structures and X-ray diffraction (XRD) confirms their high crystallinity. Scanning transmission electron microscopy reveals the crystal orientation and atomic arrangement of the specific region with atomic resolution.

Liquid Precursor-Assisted Chemical Vapor Deposition of One-Dimensional van der Waals Material NbSe: Tunable Growth for Room-Temperature Gas Sensors.

In this study, NbSe, a one-dimensional (1D) material with van der Waals (vdWs) bonding, was synthesized by chemical vapor deposition (CVD). A liquid precursor was used to overcome the difficulty of controlling the length and density of NbSe by CVD due to the high melting point of Nb. Growth proceeded horizontally in a nano-ribbon shape on the substrate in the [100] direction, which had the most stable bonding distance, resulting in a preferred orientation of the (010) plane on the out-of-plane axis.

Carrier mobility of one-dimensional vanadium selenide (VSe) monolayer and nanoribbon systems: DFT study.

Vanadium selenide (VSe) is a true one-dimensional (1D) crystal composed of atomic nanochains bonded by van der Waals (vdW) interactions. Recent experiments revealed the mechanical exfoliation of newly synthesized VSe. In this study, we predicted the electronic and transport properties of VSethrough computational analyses.

High Breakdown Current Density in Quasi-1D van der Waals Layered Material TaNiSe.

We synthesized ternary composition chalcogenide TaNiSe, a quasi-one-dimensional (Q1D) material with excellent crystallinity. To utilize the excellent electrical conductivity property of TaNiSe, the breakdown current density () according to thickness change through mechanical exfoliation was measured. It was confirmed that as the thickness decreased, the maximum breakdown voltage () increased, and at 18 nm thickness, 35 MA cm of was measured, which was 35 times higher than that of copper, which is commonly used as an interconnect material.

One-dimensional van der Waals stacked p-type crystal TaPtSe for nanoscale electronics.

Recently, ternary transition metal chalcogenides TaXSe (X = Pd or Pt) have attracted great interest as a class of emerging one-dimensional (1D) van der Waals (vdW) materials. In particular, TaPdSe has been actively studied owing to its excellent charge transport properties as an n-type semiconductor and ultralong ballistic phonon transport properties. Compared to subsequent studies on the Pd-containing material, TaPtSe, another member of this class of materials has been considerably less explored despite its promising electrical properties as a p-type semiconductor.

Ta Ni Se : 1D van der Waals Material with Ambipolar Behavior.

In this study, high-purity and centimeter-scale bulk Ta Ni Se crystals are obtained by controlling the growth temperature and stoichiometric ratio between tantalum, nickel, and selenium. It is demonstrated that the bulk Ta Ni Se crystals could be effectively exfoliated into a few chain-scale nanowires through simple mechanical exfoliation and liquid-phase exfoliation. Also, the calculation of electronic band structures confirms that Ta Ni Se is a semiconducting material with a small bandgap.

Tuning the electronic properties of highly anisotropic 2D dangling-bond-free sheets from 1D VSe chain structures.

True one-dimensional (1D) van der Waals materials can form two-dimensional (2D) dangling-bond-free anisotropic surfaces. Dangling bonds on surfaces act as defects for transporting charge carriers. In this study, we consider true 1D materials to be VSe chains, and then the electronic structures of 2D sheets composed of true 1D VSe chains are calculated.

Plasticized Polystyrene by Addition of -Diene Based Molecules for Defect-Less CVD Graphene Transfer.

Chemical vapor deposition of graphene on transition metals is the most favored method to get large scale homogenous graphene films to date. However, this method involves a very critical step of transferring as grown graphene to desired substrates. A sacrificial polymer film is used to provide mechanical and structural support to graphene, as it is detached from underlying metal substrate, but, the residue and cracks of the polymer film after the transfer process affects the properties of the graphene.

Edge Defect-Free Anisotropic Two-Dimensional Sheets with Nearly Direct Band Gaps from a True One-Dimensional Van der Waals NbSe Material.

Dangling-bond-free two-dimensional (2D) materials can be isolated from the bulk structures of one-dimensional (1D) van der Waals materials to produce edge-defect-free 2D materials. Conventional 2D materials have dangling bonds on their edges, which act as scattering centers that deteriorate the transport properties of carriers. Highly anisotropic 2D sheets, made of 1D van der Waals NbSe material, have three planar structures depending on the cutting direction of the bulk NbSe crystal.

Designed growth of porous 2D NbO with Ag nano-particles for differential detection of UV-A and UV-C.

We demonstrate the differential detection of UV-A (ultra-violet 320-400 nm region) and UV-C (100-280 nm) using porous two-dimensional (2D) NbO and additional Ag nano-particle decoration. The 2D NbO, which has band-absorption edge near the UV-A zone, was synthesized by thermodynamic conversion of 2D material NbSe (NbO has lower Gibbs formation energy than NbSe). For the differential detection (to distinguish with UV-C absorption), we decorated the Ag nano-particles on the NbO surface.

Thickness-Dependence Electrical Characterization of the One-Dimensional van der Waals TaSe Crystal.

Needle-like single crystalline wires of TaSe were massively synthesized using the chemical vapor transport method. Since the wedged-shaped single TaSe molecular chains were stacked along the b-axis by weak van der Waals interactions, a few layers of TaSe flakes could be easily isolated using a typical mechanical exfoliation method. The exfoliated TaSe flakes had an anisotropic planar structure, and the number of layers could be controlled by a repeated peeling process until a monolayer of TaSe nanoribbon was obtained.

Design of softened polystyrene for crack- and contamination-free large-area graphene transfer.

The fundamental issues related to the formation of mechanical cracks and the chemical residue during the transfer process of large-area CVD graphene by polymeric carrier-films are addressed in this work. This paper presents a method to design a new polymer carrier-film (using polystyrene (PS) and 4,4'-diisopropylbiphenyl (DIPB)) that is free from mechanical cracks and polymer residue during the transfer of large-area graphene from a metal catalyst. This new polymer carrier film shows excellent mechanical flexibility and good solubility in tetrahydrofuran solvent without any residue and it is confirmed that the graphene transfer process is excellent without mechanical destruction even over a large area.

Mechanical exfoliation and electrical characterization of a one-dimensional NbSe atomic crystal.

A novel semiconductor 1D nanomaterial, NbSe, was synthesized on a bulk scale simple vapor transport reaction between niobium and selenium. Needle-like single crystal NbSe contains numerous single NbSe chains linked by van der Waals interactions, and we confirmed that a bundle of chains can be easily separated by mechanical cleavage. The exfoliated NbSe flakes exhibit a quasi-two-dimensional layered structure, and the number of layers can be controlled using the repeated-peeling method.

Exfoliation and Characterization of V₂Se₉ Atomic Crystals.

Mass production of one-dimensional, V₂Se₉ crystals, was successfully synthesized using the solid-state reaction of vanadium and selenium. Through the mechanical exfoliation method, the bulk V₂Se₉ crystal was easily separated to nanoribbon structure and we have confirmed that as-grown V₂Se₉ crystals consist of innumerable single V₂Se₉ chains linked by van der Waals interaction. The exfoliated V₂Se₉ flakes can be controlled thickness by the repeated-peeling method.

Triangular radial NbO nanorod growth on -plane sapphire for ultraviolet-radiation detection.

NbO nanostructures with excellent crystallinities were grown on -plane sapphire and employed for ultraviolet-(UV)-radiation detection. The triangular radial NbO grown on the -sapphire substrate had a 6-fold symmetry with domain matching epitaxy on the substrate. Owing to the radial growth, the nanorods naturally connected when the deposition time increased.

CD44 is associated with tumor recurrence and is an independent poor prognostic factor for patients with localized clear cell renal cell carcinoma after nephrectomy.

CD44 has been implicated in tumor development and progression in several types of cancer. CD44 expression is altered in renal cell carcinoma (RCC) and has been suggested as a useful prognostic marker, but its prognostic role in RCC remains controversial. We investigated the expression of CD44 in a large homogeneous set of localized clear cell RCC to determine its potential prognostic value.