Scalable Atomic-Layer Tailoring of Abundant Oxide Supports Unlocks Superior Interfaces for Low-Metal-Loading Dehydrogenation.

Liquid organic hydrogen carriers (LOHCs) offer a promising solution for global hydrogen infrastructure, but their practical application faces two key challenges: sluggish dehydrogenation processes and the reliance on catalysts with high noble metal loadings. This study presents a scalable approach to reduce noble metal usage while maintaining high catalytic activity. We synthesized an ultralow Pt content (0.

Novel Roles of Catalysts in Producing High-Purity High-Pressure Hydrogen from Sodium Borohydride.

Hydrogen has received enormous attention as a clean fuel with its high specific energy (HHV=142 MJ kg). To apply hydrogen as a practically available energy vector, the direct production of high-pressure hydrogen with high purity is pivotal as it allows for circumventing the mechanical compression process. Recently, the concept of utilizing sodium borohydride (SBH) dehydrogenation as a chemical compressor that can generate high-pressure hydrogen gas was demonstrated by adopting formic acid as an acid catalyst.

A transparent p-type semiconductor designed a polarizability-enhanced strongly correlated insulator oxide matrix.

Electron-transporting transparent conducting oxides (TCOs) are a commercial reality, however, hole-transporting counterparts are far more challenging because of limited material design. Here, we propose a strategy for enhancing the hole conductivity without deteriorating the band gap () and workfunction () by Cu incorporation in a strongly correlated NiWO insulator. The optimal Cu-doped NiWO (CuNiWO) exhibits a resistivity reduction of ∼10 times NiWO as well as band-like charge transport with the hole mobility approaching 7 cm V s at 200 K, a deep of 5.

Promotion of Processability in a p-Type Thin-Film Transistor Using a Se-Te Alloying Channel Layer.

p-type thin-film transistors (pTFTs) have proven to be a significant impediment to advancing electronics beyond traditional Si-based technology. A recent study suggests that a thin and highly crystalline Te layer shows promise as a channel for high-performance pTFTs. However, achieving this still requires specific conditions, such as a cryogenic growth temperature and an extremely thin channel thickness on the order of a few nanometers.

Acceleration of NO gas sensitivity in two-dimensional SnSe by Br doping.

The authors report a Br doping effect on the NO gas sensing properties of a two-dimensional (2D) SnSe semiconductor. Single crystalline 2D SnSe samples with different Br contents are grown by a simple melt-solidification method. By analyzing the structural, vibrational as well as electrical properties, it can be confirmed that the Br impurity substitutes on the Se-site in SnSe serving as an efficient electron donor.

Study on the decisive factor for metal-insulator transitions in a LaVO Mott-Hubbard insulator.

The decisive physical parameters on electrical conduction in a LaVO Mott-Hubbard system are systematically investigated by analyzing pure, Ca-, and Sr-doped samples. The Rietveld refinement of the X-ray diffraction data indicates that a drastic change occurs along the -axis to reduce the octahedral tilt thereby relaxing the distortion for the doped compounds, in contrast to an insignificant change in the in-plane distortion. From electrical, optical, and photoemission measurements, both Ca and Sr-doping in LaVO induce insulator to metal transitions under a similar hole carrier concentration as suppressing the Mott-gap excitation.

Graphene Bridge Heterostructure Devices for Negative Differential Transconductance Circuit Applications.

Two-dimensional van der Waals (2D vdW) material-based heterostructure devices have been widely studied for high-end electronic applications owing to their heterojunction properties. In this study, we demonstrate graphene (Gr)-bridge heterostructure devices consisting of laterally series-connected ambipolar semiconductor/Gr-bridge/n-type molybdenum disulfide as a channel material for field-effect transistors (FET). Unlike conventional FET operation, our Gr-bridge devices exhibit non-classical transfer characteristics (humped transfer curve), thus possessing a negative differential transconductance.

Fermi-Level Pinning-Free WSe Transistors via 2D Van der Waals Metal Contacts and Their Circuits.

Precise control over the polarity of transistors is a key necessity for the construction of complementary metal-oxide-semiconductor circuits. However, the polarity control of 2D transistors remains a challenge because of the lack of a high-work-function electrode that completely eliminates Fermi-level pinning at metal-semiconductor interfaces. Here, a creation of clean van der Waals contacts is demonstrated, wherein a metallic 2D material, chlorine-doped SnSe (Cl-SnSe ), is used as the high-work-function contact, providing an interface that is free of defects and Fermi-level pinning.

Direct Observation of Orbital Driven Strong Interlayer Coupling in Puckered Two-Dimensional PdSe.

Interlayer coupling between individual unit layers is known to be critical in manipulating the layer-dependent properties of two-dimensional (2D) materials. While recent studies have revealed that several 2D materials with significant degrees of interlayer interaction (such as black phosphorus) show strongly layer-dependent properties, the origin based on the electronic structure is drawing intensive attention along with 2D materials exploration. Here, the direct observation of a highly dispersive single electronic band along the interlayer direction in puckered 2D PdSe as an experimental hallmark of strong interlayer couplings is reported.

Antiperovskite Gd SnC: Unusual Coexistence of Ferromagnetism and Heavy Fermions in Gd Lattice.

Inverted structures of common crystal lattices, referred to as antistructures, are rare in nature due to their thermodynamic constraints imposed by the switched cation and anion positions in reference to the original structure. However, a stable antistructure formed with mixed bonding characters of constituent elements in unusual valence states can provide unexpected material properties. Here, a heavy-fermion behavior of ferromagnetic gadolinium lattice in Gd SnC antiperovskite is reported, contradicting the common belief that ferromagnetic gadolinium cannot be a heavy-fermion system due to the deep energy level of localized 4f-electrons.

Stoner enhancement from interstitial electrons in YC toward a spontaneous ferromagnetic electride.

The evolutionary magnetism associated with the interlayer spacing in two-dimensional (2D) YC electrides has been investigated by first-principles total-energy calculations based on density functional theory. Several structures with different c-axis parameters around the optimized value were taken into our consideration. Mapping of the electron localization function shows that the interstitial electron is strongly localized at the body center position (denoted as the X-site) in the primitive rhombohedral unit cell, serving as an anion which is ionically bonded with the cationic framework of the YC layer.

Effects of Intense Pulsed Light (IPL) Rapid Annealing and Back-Channel Passivation on Solution-Processed In-Ga-Zn-O Thin Film Transistors Array.

We report on the effects of the intense pulsed light (IPL) rapid annealing process and back-channel passivation on the solution-processed In-Ga-Zn-O (IGZO) thin film transistors (TFTs) array. To improve the electrical properties, stability and uniformity of IGZO TFTs, the oxide channel layers were treated by IPL at atmospheric ambient and passivated by photo-sensitive polyimide (PSPI). When we treated the IGZO channel layer by the IPL rapid annealing process, saturation field effect mobility and subthreshold swing (S.

Author Correction: Ferromagnetic quasi-atomic electrons in two-dimensional electride.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Ferromagnetic quasi-atomic electrons in two-dimensional electride.

An electride, a generalized form of cavity-trapped interstitial anionic electrons (IAEs) in a positively charged lattice framework, shows exotic properties according to the size and geometry of the cavities. Here, we report that the IAEs in layer structured [GdC]·2e electride behave as ferromagnetic elements in two-dimensional interlayer space and possess their own magnetic moments of ~0.52 μ per quasi-atomic IAE, which facilitate the exchange interactions between interlayer gadolinium atoms across IAEs, inducing the ferromagnetism in [GdC]·2e electride.

Influence of Pd Doping on Electrical and Thermal Properties of -Type CuBiTeSe Alloys.

Doping is known as an effective way to modify both electrical and thermal transport properties of thermoelectric alloys to enhance their energy conversion efficiency. In this project, we report the effect of Pd doping on the electrical and thermal properties of -type CuBiTeSe alloys. Pd doping was found to increase the electrical conductivity along with the electron carrier concentration.

Abnormal Optoelectric Properties of Two-Dimensional Protonic Ruthenium Oxide with a Hexagonal Structure.

Two-dimensional structures can potentially lead to not only modulation of electron transport but also the variations of optical property. Protonic ruthenium oxide, a two-dimensional atomic sheet material, has been synthesized, and its optoelectric properties have been investigated. The results indicate that protonic ruthenium oxide is an excellent candidate for use as a flexible, transparent conducting material.

Interband Transitions in Monolayer and Few-Layer WSe Probed Using Photoexcited Charge Collection Spectroscopy.

Transition-metal dichalcogenides are currently under rigorous investigation because of their distinct layer-dependent physical properties originating from the corresponding evolution of the band structure. Here, we report the highly resolved probing of layer-dependent band structure evolution for WSe using photoexcited charge collection spectroscopy (PECCS). Monolayer, few-layer, and multilayer WSe can be probed in top-gate field-effect transistor platforms, and their interband transitions are efficiently observed.

Tuning the Spin-Alignment of Interstitial Electrons in Two-Dimensional YC Electride via Chemical Pressure.

We report that the spin-alignment of interstitial anionic electrons (IAEs) in two-dimensional (2D) interlayer spacing can be tuned by chemical pressure that controls the magnetic properties of 2D electrides. It was clarified from the isovalent Sc substitution on the Y site in the 2D YC electride that the localization degree of IAEs at the interlayer becomes stronger as the unit cell volume and c-axis lattice parameter were systematically reduced by increasing the Sc contents, thus eventually enhancing superparamagnetic behavior originated from the increase in ferromagnetic particle concentration. It was also found that the spin-aligned localized IAEs dominated the electrical conduction of heavily Sc-substituted YC electride.

Strong Localization of Anionic Electrons at Interlayer for Electrical and Magnetic Anisotropy in Two-Dimensional YC Electride.

We have synthesized a single crystalline YC electride of centimeter-scale by floating-zone method and successfully characterized its anisotropic electrical and magnetic properties. In-plane resistivity upturn at low temperature together with anisotropic behavior of negative magnetoresistance is ascribed to the stronger suppression of spin fluctuation along in-plane than that along the c-axis, verifying the existence of magnetic moments preferred for the c-axis. A superior magnetic moment along the c-axis to that along the in-plane direction strongly demonstrates the anisotropic magnetism of YC electride containing a magnetically easy axis.

First-Principles Prediction of Thermodynamically Stable Two-Dimensional Electrides.

Two-dimensional (2D) electrides, emerging as a new type of layered material whose electrons are confined in interlayer spaces instead of at atomic proximities, are receiving interest for their high performance in various (opto)electronics and catalytic applications. Experimentally, however, 2D electrides have been only found in a couple of layered nitrides and carbides. Here, we report new thermodynamically stable alkaline-earth based 2D electrides by using a first-principles global structure optimization method, phonon spectrum analysis, and molecular dynamics simulation.

Metallic conduction induced by direct anion site doping in layered SnSe2.

The emergence of metallic conduction in layered dichalcogenide semiconductor materials by chemical doping is one of key issues for two-dimensional (2D) materials engineering. At present, doping methods for layered dichalcogenide materials have been limited to an ion intercalation between layer units or electrostatic carrier doping by electrical bias owing to the absence of appropriate substitutional dopant for increasing the carrier concentration. Here, we report the occurrence of metallic conduction in the layered dichalcogenide of SnSe2 by the direct Se-site doping with Cl as a shallow electron donor.

Metal Semiconductor Field-Effect Transistor with MoS2/Conducting NiO(x) van der Waals Schottky Interface for Intrinsic High Mobility and Photoswitching Speed.

Molybdenum disulfide (MoS2) nanosheet, one of two-dimensional (2D) semiconductors, has recently been regarded as a promising material to break through the limit of present semiconductors. With an apparent energy band gap, it certainly provides a high carrier mobility, superior subthreshold swing, and ON/OFF ratio in field-effect transistors (FETs). However, its potential in carrier mobility has still been depreciated since the field-effect mobilities have only been measured from metal-insulator-semiconductor (MIS) FETs, where the transport behavior of conducting carriers located at the insulator/MoS2 interface is unavoidably interfered by the interface traps and gate voltage.

Trap density probing on top-gate MoS₂ nanosheet field-effect transistors by photo-excited charge collection spectroscopy.

Two-dimensional (2D) molybdenum disulfide (MoS₂) field-effect transistors (FETs) have been extensively studied, but most of the FETs with gate insulators have displayed negative threshold voltage values, which indicates the presence of interfacial traps both shallow and deep in energy level. Despite such interface trap issues, reports on trap densities in MoS₂ are quite limited. Here, we probed top-gate MoS₂ FETs with two- (2L), three- (3L), and four-layer (4L) MoS₂/dielectric interfaces to quantify deep-level interface trap densities by photo-excited charge collection spectroscopy (PECCS), and reported the result that deep-level trap densities over 10(12) cm(-2) may exist in the interface and bulk MoS₂ near the interface.