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1D structures/patterns (e.g., line defect arrays, 1D Moiré patterns) embedded in 2D materials provide fascinating platforms for exploring versatile intriguing phenomena, for example, 1D Luttinger liquids and charge density waves (CDWs). Despite persistent efforts, incorporating periodic 1D patterns into 2D materials remains an ongoing pursuit. Herein, the direct preparation of monolayer 1D‐defect‐induced Co4Te7 superlattices (with periodic Te defect lines in the upper Te layer in 1T‐CoTe2) is reported, on lattice‐matched SrTiO3(001) (STO(001)) substrates via molecular beam epitaxy (MBE). Utilizing on‐site scanning tunneling microscopy/spectroscopy (STM/STS) combined with density functional theory (DFT) calculations, the detailed atomic structure of monolayer Co4Te7 is identified, and its formation mechanisms from the synergistic effects of the Co/Te precursor ratio and adlayer‐substrate interfacial coupling are uncovered. The potential flat‐band feature of the monolayer Co4Te7 is also unveiled. This work should hereby offer valuable insights into the engineering of periodic 1D‐defect patterns in 2D materials, as well as the atomic‐scale structure and electronic property characterizations, thus paving ways for their intriguing property investigations. [ABSTRACT FROM AUTHOR]

2D semiconducting transition metal dichalcogenides (TMDCs), most with a formula of MX2 (M=Mo, W; X=S, Se, etc.), have emerged as promising channel materials for next‐generation integrated circuits, considering their dangling‐bond‐free surfaces, moderate bandgaps, relatively high carrier mobilities, etc. Wafer‐scale preparation of 2D MX2 films holds fundamental significance for realizing their applications. Chemical vapor deposition (CVD) is recognized as the most promising method for preparing electronic‐grade 2D MX2 films. This review hereby summarizes the recent progress in CVD syntheses of wafer‐scale 2D MX2 films and their applications in logic operations, data storage, and image capturing/processing related fields. The first part focuses on the wafer‐scale syntheses of 2D MX2 films through designing homogeneous metal precursor supply routes (e.g., precoating soluble precursor, feeding gaseous precursor, designing independent multisource supply or face‐to‐face metal precursor supply routes). The second part highlights the epitaxial growth of monolayer MX2 single crystals on single‐crystal Au substrates and well‐designed sapphire substrates. The third part introduces various functional device/circuit related applications of CVD‐derived 2D MX2 wafers. Finally, challenges and prospects are discussed from the viewpoints of the controlled synthesis, reliable characterization, and damage‐free transfer of 2D MX2, as well as the fabrication and integration of high‐performance devices. [ABSTRACT FROM AUTHOR]

As an emerging class of semiconducting transition metal dichalcogenides (TMDCs), two-dimensional (2D) rhenium dichalcogenides (ReX2, X = S or Se) have recently aroused great research interest due to their unique anisotropic structure (1T' phase), and the related novel properties and applications. Recently, many efforts have been devoted to the controllable syntheses of high-quality monolayer or few-layer ReX2 flakes/films by chemical vapor deposition (CVD), wherein the metallic Au foil is found to be a unique substrate, due to the relatively strong interfacial coupling between monolayer ReX2 and Au. And the conductive nature of Au enables in situ characterizations of the as-grown ReX2 samples, which is essential for exploring the fundamental properties and internal growth mechanisms. Hereby, this review focuses on the recent progresses on the CVD syntheses and in situ characterizations of high-quality monolayer ReX2 flakes/films and their heterostructures with graphene on Au foils. The effects of Au foils on improving the crystal quality and inducing the growth of monolayer ReX2 single crystals are intensively addressed. The crystallinity, domain morphology, atomic and electronic structures, as well as the growth behaviors of monolayer ReX2 flakes/films and graphene/ReX2 heterostructures on Au revealed by in situ characterization techniques are also highlighted. As contrasts, the growth behaviors of monolayer or few-layer ReX2 on insulating substrates are also discussed. Besides, the potential applications of 2D ReX2 in new-generation electronic, optoelectronic devices, and energy-related fields are also introduced. Finally, future research directions are also prospected for propelling the practical applications of 2D ReX2 materials in more versatile fields. [ABSTRACT FROM AUTHOR]

Spraying extinguishing agent can effectively prevent forest fire, but its effect on soil chemical properties under forest is not clear. This study aimed to examine the influence of forest fire and fire extinguishing agent on soil chemical properties. Soil samples at depth of 0~10 cm and 10~20 cm were collected immediately (early) and 3 months later (later) after fire and fire extinguishing by simulating 3 bushfire gradients including without fire, moderate and severe fire in the field and 3 extinguishing agent quantities such as without extinguishing agent, small dose and high dose extinguishing agent. The indoor chemical properties of the collected soil were determined, including pH, conductivity, phosphatase activity, invertase activity, available phosphorus and available potassium, and the effects of different intensity fires and different doses extinguishing agent treatment on soil chemical properties under different spatial and temporal distributions were illustrated by comparative analysis of various chemical indexes and their changes. Results indicated that under the condition of the same intensity of fire disturbance, the use of fire extinguishing agent had no significant effect on the pH of the initial soil; without fire extinguishing agent, the use of heavy fire significantly increased the pH of the initial deep soil. Fire and extinguishing agent will improve the conductivity of surface soil, the effect is not significant; under the condition of severe fire, the use of high dose extinguishing agent significantly increases the conductivity of deep soil after 3 months of fire. The use of fire extinguishing agent alone inhibits the activity of the surface soil phosphatase, and the activity of sucrose enzyme promotes it, but the use of the extinguishing agent in burning disturbance can relieve the inhibition of the activity of phosphatase by fire. The law of immediate soil phosphatase and sucrose enzyme activity decreased with the increase of depth under the combination of fire and extinguishing agent. The effect of fire on the content of available phosphorus in surface soil is higher than that of deep soil, and there is no significant difference between the content of available phosphorus and the absence of fire extinguishing agent in soil sprayed with small dose extinguishing agent under severe burning conditions. The activities of available phosphorus and phosphatase were destroyed by fire and its products, and the effects of different soil layers were the same. The content of available potassium in surface soil was significantly improved in a certain period of time without fire extinguishing agent, and the effect of free interference spraying extinguishing agent on soil available potassium content was not significant in a certain period of time. On the whole, moderate fire disturbance is beneficial to promote the material circulation within the forest ecosystem. Spraying small dose fire extinguishing agent is beneficial to forest fire prevention and control, and does not cause soil eutrophication, is conducive to protecting forest ecosystem balance, and provides theoretical and practical guidance for fire prevention and control under high voltage transmission lines. The effects on soil physics and biological properties needs further exploration. [ABSTRACT FROM AUTHOR]

2D noble transition metal dichalcogenides (nTMDCs, PdX 2 and PtX 2 , where X═S, Se, Te) have emerged as a new class of 2D materials, owing to their unique puckered pentagonal structure in 2D PdS 2 and PdSe 2 , largely tunable band structures or band gaps with decreasing the layer thickness at the 2D limit, strong interlayer interactions, superior optoelectronic properties, high edge catalytic properties, etc. Directly synthesizing 2D nTMDCs domains or thin films with large-area uniformity, tunable thickness, and high crystalline quality is the premise for exploring these salient properties and developing a wide range of applications. Hereby, this review summarizes recent progress in the direct syntheses and characterizations of 2D nTMDCs, mainly focusing on the thermally assisted conversion (TAC) and chemical vapor deposition (CVD) methods, by using various metal and chalcogen-contained precursors. Meanwhile, the applications of directly synthesized 2D nTMDCs in various fields, such as high-performance field effect transistors (FETs), broadband photodetectors, superior catalysts in hydrogen evolution reactions, and ultra-sensitive piezo resistance sensors, are also discussed. Finally, challenges and prospects regarding the direct syntheses of high-quality 2D nTMDCs and their applications in next-generation electronic and optoelectronic devices, as well as novel catalysts beyond noble metals are overviewed., (© 2025 Wiley‐VCH GmbH.)

Single-crystal Au(111), renowned for its chemically inert surface, long-range "herringbone" reconstruction, and high electrical conductivity, has long served as an exemplary template in diverse fields, e.g. , crystal epitaxy, electronics, and electrocatalysis. However, commercial Au(111) products are high-priced and limited to centimeter sizes, largely restricting their broad applications. Herein, a low-cost, high-reproducible method is developed to produce 4 in. Au(111) single crystals from commercial Au foils, via an abnormal grain growth process. This methodology involves the initial preparation of a (100)-textured Au polycrystalline foil, followed by the evolution and continuous expansion of an Au(111) abnormal grain through one-site stress loading and stress-relief annealing in an Ar/H 2 atmosphere. Theoretical simulations indicate that stress/strain and high-temperature treatments in the H 2 atmosphere induce an intermediate disordered state, facilitating the evolution from polycrystalline Au(100) foil to single-crystal Au(111) foil. Furthermore, the resulting Au(111) foils have been utilized as model substrates for the oriented growth of two-dimensional transition metal dichalcogenides and their heterostructures with graphene. This work hereby puts forward an effective approach for large-scale, cost-effective production of metal single crystals, potentially revolutionizing their applications across various fields, from materials sciences to electronics and catalysis.

2D transition metal dichalcogenides (2D TMDCs) have attracted intensive interest in physics and materials science-related fields, due to their exotic properties (e.g., superconductivity, charge density wave (CDW) phase transition, magnetism, electrocatalytic property). Intercalation of native metal atoms in the layered 2D TMDCs (e.g., from VS 2 to V 5 S 8 by V intercalation) can afford new stoichiometric ratios, phase states, and thus rich properties. This review hereby summarizes the recent progress in the controllable syntheses, structure characterizations, and property explorations of self-intercalated 2D transition metal chalcogenides (TMCs), with the metal elements focusing on group-V, VI, and VIII metals. The self-intercalation-related synthetic strategies will be introduced via chemical vapor deposition (CVD) and molecule beam epitaxy (MBE), especially by tuning the chemical potentials of intercalated metal elements, growth promoters, substrates, etc. Additionally, the structure/phase identifications of the self-intercalated 2D TMCs through various characterization techniques will be overviewed. More significantly, the intriguing properties in such 2D TMCs will be thoroughly discussed, such as the thickness- or composition-dependent magnetism, CDW phase transition, electrocatalytic property, etc. Finally, challenges and prospects are proposed for developing new self-intercalated 2D materials and their heterostructures and exploring their unique properties and applications., (© 2025 Wiley‐VCH GmbH.)

The epitaxial growth of wafer-scale two-dimensional (2D) semiconducting transition metal dichalcogenides (STMDCs) single crystals is the key premise for their applications in next-generation electronics. Despite significant advancements, some fundamental factors affecting the epitaxy growth have not been fully uncovered, e.g., interface coupling strength, adlayer-substrate lattice matching, substrate step-edge-guiding effects, etc. Herein, we develop a model system to tackle these issues concurrently, and realize the epitaxial growth of wafer-scale monolayer tungsten disulfide (WS 2 ) single crystals on the Au(111) substrate. This epitaxial system is featured with good adlayer-substrate lattice matching, obvious step-edge-guiding effect for the unidirectionally aligned nucleation/growth, and relatively weaker interfacial interaction than that of monolayer MoS 2 /Au(111), as evidenced by the evolution of a uniform Moiré pattern and an intrinsic band gap, according to on-site scanning tunneling microscopy/spectroscopy (STM/STS) characterizations and density functional theory calculations. Intriguingly, the unidirectionally aligned monolayer WS 2 domains along the Au(111) steps can behave as ultrasensitive templates for surface-enhanced Raman scattering detection of organic molecules, due to the obvious charge transfer occurred at substrate step edges. This work should hereby deepen our understanding of the epitaxy mechanism of 2D STMDCs on single-crystal substrates, and propel their wafer-scale production and applications in various cutting-edge fields.

Ultrathin PtSe 2 ribbons can host spin-polarized edge states and distinct edge electrocatalytic activity, emerging as a promising candidate for versatile applications in various fields. However, the direct synthesis is still challenging and the growth mechanism is still unclear. Herein, the arrayed growth of ultrathin PtSe 2 ribbons on bunched vicinal Au(001) facets, via a facile chemical vapor deposition (CVD) route is reported. The ultrathin PtSe 2 flakes can transform from traditional irregular shapes to desired ribbon shapes by increasing the height of bunched and unidirectionally oriented Au steps (with step height h step ) is found. This crossover, occurring at h step ≈ 3.0 nm, defines the tailored growth from step-flow to single-terrace-confined modes, as validated by density functional theory calculations of the different system energies. On the millimeter-scale single-crystal Au(001) films with aligned steps, the arrayed ultrathin PtSe 2 ribbons with tunable width of ≈20-1000 nm, which are then served as prototype electrocatalysts for hydrogen evolution reaction (HER) is achieved. This work should represent a huge leap in the direct synthesis and the mechanism exploration of arrayed ultrathin transition-metal dichalcogenides (TMDCs) ribbons, which should stimulate further explorations of the edge-related physical properties and practical applications., (© 2024 Wiley‐VCH GmbH.)

Kagome materials have recently garnered substantial attention due to the intrinsic flat band feature and the stimulated magnetic and spin-related many-body physics. In contrast to their bulk counterparts, two-dimensional (2D) kagome materials feature more distinct kagome bands, beneficial for exploring novel quantum phenomena. Herein, we report the direct synthesis of an ultrathin kagome-structured Co-telluride (Co 9 Te 16 ) via a molecular beam epitaxy (MBE) route and clarify its formation mechanism from the Co-intercalation in the 1T-CoTe 2 layers. More significantly, we unveil the flat band states in the ultrathin Co 9 Te 16 and identify the real-space localization of the flat band states by in situ scanning tunneling microscopy/spectroscopy (STM/STS) combined with first-principles calculations. A ferrimagnetic order is also predicted in kagome-Co 9 Te 16 . This work should provide a novel route for the direct synthesis of ultrathin kagome materials via a metal self-intercalation route, which should shed light on the exploration of the intriguing flat band physics in the related systems.

Epitaxial growth of wafer-scale monolayer semiconducting transition metal dichalcogenide single crystals is essential for advancing their applications in next-generation transistors and highly integrated circuits. Several efforts have been made for the growth of monolayer MoS 2 single crystals on high-symmetry Au(111) and sapphire substrates, while more prototype growth systems still need to be discovered for clarifying the internal mechanisms. Herein, we report the epitaxial growth of unidirectionally aligned monolayer MoS 2 domains and single-crystal films on low-symmetry Au(101) vicinal facets via a facile chemical vapor deposition method. On-site scanning tunneling microscopy observations reveal the formation of a specific rectangular Moiré pattern along the [101̅] step edge of Au(101) and along its perpendicular direction. The perfect lattice constant matching of MoS 2 /Au(101) along the substrate high-symmetry directions ( i.e. , Au[101̅], Au [010]) as well as the step-edge-guiding effect are proposed to facilitate the robust epitaxy. Multiscale characterizations further confirm the domain-boundary-free feature of the monolayer MoS 2 films merged by unidirectionally aligned monolayer domains. This work hereby puts forward a symmetry mismatched epitaxial system for the direct synthesis of monolayer MoS 2 single crystals, which should deepen our understanding about the epitaxy of 2D layered materials and propel their applications in various fields.

Moiré superlattices formed by the stacking of two-dimensional (2D) transition metal dichalcogenide lattices on substrate lattices have been reported to imply a crucial effect on the electronic properties of 2D materials ( e.g. , band gap, doping level) and their physical properties. Herein, we report the direct observation of various striped moiré superstructures for monolayer WSe 2 on the Au(100) facet, due to the lattice symmetry difference and relative rotation. The periodicities or the inter-stripe distances for striped superstructures fall in a range of 0-15 nm or 0-3 nm after relatively low or high temperature annealing processes, respectively. The diverse striped moiré superstructures then served as perfect platforms for examining the electronic band gap tunability for monolayer WSe 2 /Au(100) by using scanning tunneling microscopy/spectroscopy (STM/STS), which increases from ∼1.59 eV to ∼1.90 eV with increasing moiré periods from ∼1.62 to ∼11.58 nm. The coupling strength of monolayer WSe 2 /Au(100) with various striped patterns is thus proposed to be modulated by the different relative orientations. This work should hereby provide some fundamental references for the domain orientation control, interface coupling strength, and application explorations of two-dimensional layered materials in future electronics and optoelectronics.