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Cu3Sn was recently predicted to host topological Dirac fermions, but related research is still in its infancy. The growth of large and high-quality Cu3Sn single crystals is, therefore, highly desired to investigate the possible topological properties. In this work, we report the single crystal growth of Cu3Sn by Czochralski (CZ) method. Crystal structure, chemical composition, and transport properties of Cu3Sn single crystals were analyzed to verify the crystal quality. Notably, compared to the mm-sized crystals from a molten Sn-flux, the cm-sized crystals obtained by the CZ method are free from contamination from flux materials, paving the way for the follow-up works.

The study of crystals is like the beginning of solid state physics. Crystallography was developed rapidly with the discovery of X-ray. Recently, the era of physics is enriching with the emergence of new material groups such as graphene, topological insulators, and TMD materials. In a way, it is very interesting to see that the providence of the universe and the philosophy of life are reflected in the small crystal structure. However, unfortunately, little is known about when and how crystal growth began. How did our ancestors in the beginning grow and study crystal? This article examines the history of early crystal growth, the development of crystallography, and the relationship between crystallography and physics.

Wafer-scale growth of metallic films into single crystals is challenging owing to the large lattice mismatch and uncontrollable stacking of atoms during deposition. Here, single-crystal Ag(111) films are grown on flat Cu(111) buffer layers using atomic sputtering epitaxy, notwithstanding the large (approximately 13%) Ag/Cu lattice mismatch. Phenomenologically, the mismatch strain is localised to the first Ag monoatomic interface layer, without spreading into adjacent Ag layers. This perfect strain absorber occurs owing to regulated in-plane displacements of Ag atoms at the periodic colocalisation loci of Ag and Cu atoms. This extreme case does not require collective cooperation of dislocated atoms as opposed to the case of strain relaxation, thereby enabling defect-free growth of Ag films. The resulting film surfaces are inherently ultraflat and thus advantageous for perfect reflectors and plasmonic devices.

Perfectionism as a construct has received increasing attention in recent years, in particular with regard to its potentially debilitating effects. In this critical literature review, the prevalence and development of perfectionism in school-age musicians are examined, with an eye to the implicit values of neoliberalism and settler colonialism represented in music curricula. Parent, teacher, and cultural influences are considered, as well as the role of perfectionism in children’s experience of music performance anxiety. Suggestions that perfectionism in this context may be a product of punitive methods in education and inequitable distribution of resources are discussed. Recommendations are made for pedagogical practices and research with children, as well as implications for parents, with specific attention focused on the need to deviate from the idea that perfect performances are the only measurements of success in music.

The development of advanced hierarchical anode materials has recently become essential to achieving high-performance sodium-ion batteries. Herein, we developed a facile and cost-effective scheme for synthesizing graphene-wrapped, nitrogen-rich carbon-coated iron sulfide nanofibers (FeS@NCG) as an anode for SIBs. The designed FeS@NCG can provide a significant reversible capacity of 748.5 mAh g

The intrinsic nature of electronic transport has been screened by the carrier scattering at grain boundaries in two-dimensional noble metals, such as copper. Here, by realizing the impossible assumption of growing without grain boundaries in thin films, we demonstrate that the transport by hole carriers in 2D copper is the intrinsic nature, which has been screened by the scattering of carriers at grain boundaries. Unlike the grain boundaries, twin boundaries are invisible to conduction carriers, but even a slight tilt from regular twin boundaries is recognized as grain boundaries to electrons, so only complete suppression of grain boundaries can reveal the hidden hole-like characteristic of 2D-single crystal copper. The hole carriers can be explained by the concave Fermi surface of the 2D single-crystal copper, which suggests a breakthrough in manipulating the polarity of majority carriers in metals based on grain boundary engineering in a 2D geometry.

Can we control the flatness of the surface of a thin film down to the level of individual atoms? Can we further make such an ultraflat surface on a wafer scale? For such purposes, the current deposition methods, including molecular beam epitaxy (MBE), atomic layer deposition (ALD) and conventional sputtering methods, are still not adequate. In this article, we introduce a novel thin film deposition technique developed by modifying a simple sputtering method to make atomically flat metallic surfaces and a new way to investigate the structural details of thin films grown at the atomic level. For thin film, heteroepitaxial growth of a crystalline film on a different crystalline substrate is usual, and the lattice mismatch between the crystalline film and the substrate occurring in heteroepitaxy produces many misfits at the interface, which create various defects, including dislocations and grain boundaries that eventually lead to a rough surface and the deterioration of the overall quality of the crystal. The metamorphic growth method utilizing the extended atomic distance mismatch (EADM) helps to achieve successful growth of thin films in spite of a large lattice mismatch by calculating the match for a relatively long period in advance. Having an ultraflat surface for thin films made of metals such as copper has many advantages. Several advantages and possible applications of metal thin films with ultraflat surfaces are introduced.

Constructing a mono-atom step-level flat material surface is challenging, especially for thin films, because it is prohibitively difficult for trillions (1012) of clusters nucleated on a 2-inch wafer to coherently merge into a single-orientation thin film. The rough metal surface limits surface–plasmon propagation and acts as a valley for atoms deposited during the growth of the two-dimensional material. Recently, various flat-surface-assisted phenomena have been discovered, including large oxidation resistance of an atomically flat copper (Cu) surface. In this study, we describe in detail the initial growth of Cu(111) thin films with mono-atom step-level flat surfaces. We demonstrated experimentally that the individual deposition of single atoms using atomic sputtering epitaxy induces trillions of islands to coherently merge into a coplanar layer, eventually forming a mono-atom step-level flat surface. Theoretical calculations supported the fact that, when the sputtered particles are single atoms, rapid surface diffusion ensures the formation of highly aligned single-crystal nanodroplets that can be merged into a large domain with a coherent coplanar layer. These findings will open a new avenue in thin-film growth research and represent a watershed in terms of improved efficiency and lifespan of devices in most fields using metal electrodes, as well as metal nanoscience research.

Li

We report on highly transparent conductive hybrid thin-films based on copper (Cu)-mesh structures combined with conductive polymer films. The hybrid films show outstanding optical and electrical properties (transmittance of 81.7% at a wavelength of 550 nm, sheet resistance of 71.3 Ω/sq). The effective current collecting property of metal mesh structures as well as the excellent current spreading property of the conducting polymer enables the high performance of the hybrid transparent electrodes. Organic light-emitting diodes (OLEDs) employing the hybrid transparent electrodes result in 2.0-fold enhanced current and power efficiencies, compared to the control polymer electrode-based OLED without current collecting metal mesh structures. The results present that Cu-mesh structures combined with conductive polymer films show great promise for applications in low-cost, flexible indium tin oxide-free OLEDs.

High-quality epitaxial Cu2O (111) thin films were obtained from single-crystal Cu (111) thin films by rapid thermal oxidation at 800 °C. X-ray diffraction and electron backscattering diffraction analyses indicated that the films were pure Cu2O phase and well aligned along the [111] direction. Microscopic imaging of the films revealed a unique surface morphology in the form of a plateau grain network a few microns in size, which has never been achieved previously in this semiconductor. From the absorption coefficient and its first derivative, all of the characteristic optical transitions from the yellow to the indigo series, as well as excitonic transitions, were consistent with those observed from high-quality bulk Cu2O. The exceptional quality of our films was further verified by a very weak defect-induced photoluminescence, which typically dominates in natural-growth Cu2O crystals. We believe that our study represents a step towards the synthesis of high-quality oxide films having unusual surface morphologies.

Cu2O has been investigated for decades to understand the complex nature of oxidation and to utilize its high catalytic activity and intrinsic p-type character. However, the structures and intrinsic...

The single-crystalline copper (Cu) thin film is a platform substrate for the growth of numerous materials and has been a significant issue for the scientific community. The primary concern is the i...

We synthesized polycrystalline ZnFe2O4 nanofibers via a facile electrospinning and annealing process. The ZnFe2O4 nanofibers exhibit continuous frameworks and uniform porosity through the abrupt combustion of the polymer and crystallization of inorganic elements. This well-defined structure and morphology facilitates Li+ transport, enhances the effective contact area with the electrolyte, and offers abundant active sites. For the ZnFe2O4 nanofiber anode, the reversible capacity reaches 753 mAh g−1 after 200 cycles at the high current density of 5 A g−1 and the anode shows excellent rate performance. The enhanced electrochemical performance can be attributed to the one-dimensional nanostructure and shortened diffusion pathways, which ensure full conversion reactions during lithiation-delithiation between Zn, Fe, and Li+, relieve volume expansion, and prevent pulverization/aggregation upon prolonged cycling at high current densities. Thus, we believe that ZnFe2O4 nanofibers present great potential as anode materials for Li-ion batteries.

We synthesized nanoarchitectures comprising γ-Fe2O3@C nanofibers with one-dimensional rice-panicle-like morphologies via a facile electrospinning and annealing process for use as anodes in lithium-ion batteries (LIBs). A thin carbon layer grown on the surface of γ-Fe2O3 provides a synergistic effect to relieve the stress and alleviate the volume expansion occurring during the lithium-ion insertion/extraction process. The unique structure not only offers good electron transport routes, but also enhances the lithium-ion conductive channels, resulting in excellent electrochemical activity and electrical conductivity of the LIB anode material. A high reversible specific capacity of 1252 mAh g−1 was achieved after 200 cycles even at the current density of 10 A g−1. When examined at the scan rate of 5 mV s−1, a high capacitive contribution ratio of 88.5% was achieved. The short lithium-ion diffusion pathways avoid structural damage to the active material and provide excellent rate capacities. This work suggests a new method to improve the electrochemical performance of LIBs through the synergistic design of uniquely structured metal oxides.

We demonstrated the new strip-level EMI shielding process with a spray method. Test PKGs having dimension of 300um width and l, 200um height were fabricated to evaluate feasibility of strip-level EMI shielding. As a result, spray can coat the total area of trench inner side wall with the special spray coating material and optimized spray parameters. Moreover, we measured the near-field shielding effectiveness(SE) of sputtering and spray films. 5.9um-thick sputtering one and 5.4um-thick Ag ink sprayed were prepared and measured in near E- and H-field in the range of 30MHz∼1.5GHz. In E-field, The SE results showed 21dB at 800MHz and 55dB at 100MHz. In H-field, the SE result of 5.4um-thick Ag ink was 1∼2dB higher than 5.9um-thick Sus/Cu/Sus film.

There has been growing interest in organic-inorganic hybrid perovskites as a promising candidate for optoelectronic applications due to their superior physical properties. Despite this, most of the reported perovskite devices based on polycrystalline thin films suffer immensely from poor stability and high trap density owing to grain boundaries limiting their performance. Perovskite single crystal structures have been recently explored to construct stable devices and reduce the trap density compared to their thin-film counterparts. We present a novel method of growing sizable CH

Oxidation can deteriorate the properties of copper that are critical for its use, particularly in the semiconductor industry and electro-optics applications1–7. This has prompted numerous studies exploring copper oxidation and possible passivation strategies8. In situ observations have, for example, shown that oxidation involves stepped surfaces: Cu2O growth occurs on flat surfaces as a result of Cu adatoms detaching from steps and diffusing across terraces9–11. But even though this mechanism explains why single-crystalline copper is more resistant to oxidation than polycrystalline copper, the fact that flat copper surfaces can be free of oxidation has not been explored further. Here we report the fabrication of copper thin films that are semi-permanently oxidation resistant because they consist of flat surfaces with only occasional mono-atomic steps. First-principles calculations confirm that mono-atomic step edges are as impervious to oxygen as flat surfaces and that surface adsorption of O atoms is suppressed once an oxygen face-centred cubic (fcc) surface site coverage of 50% has been reached. These combined effects explain the exceptional oxidation resistance of ultraflat Cu surfaces.

The magnetic permeability and thickness of magnetic films and their effects on the EMI shielding effectiveness at 1 MHz were investigated. Various kinds of magnetic films having a thickness of 100μm~500μm and a permeability of 50μ~300μ were fabricated. 2D and 3D test vehicles were employed for measuring near-field EMI shielding effectiveness under magnetic source condition. By utilizing 2D and 3D test vehicles, the effects of various magnetic materials on the near-field EMI shielding effectiveness under H-field sources were studied at a low frequency of 1MHz. As a result, we found that the reduction rate of H-field SE is 8.57%, which is very similar to the total opening area of the four sides. the near H-field SE is affected as a logarithmic function of permeability and thickness equally

We studied and demonstrated high-performance Ag epoxy composites. A variety of shaped Ag particles were teste to optimize the electrical properties and mechanical reliability. The resulting Ag epoxy composites containing flake-shaped Ag particles showed less than 5×10−7Ω·m electrical conductivity and about 20mΩ series-resistance of PKG daisy chain, which directly corresponded to the excellent shield effectiveness. The shield effectiveness of resulting EMI shielding layer made of Ag and matrix is as high as 60dB, 65dB, 70dB at 5um, 10um, 20um-thick film, respectively by ASTM standard. We studied that how various factors, such as curing temperature, Ag contents, and film thickness, effects the electrical properties of shielding material and FCBGA package. It was found that the resistivity of conductive shielding material and the series-resistance were affected by the curing temperature than the curing time. Additionally, we demonstrated the electrical properties of AgCu epoxy composites.

These days of astrophysics are full of exciting discoveries. Gravitational waves are directly found for the first time by Laser Interferometer Gravitational-wave Observatory. Merging of compact astrophysical objects (neutron star and neutron star) is detected via multi-messengers of gravitational wave and all wavelengths of photons for the first time by worldwide observatories on ground and in space. Interesting unknowns of the gamma-ray sky are introduced by Fermi, and many details of gamma-ray bursts (GRBs) become unveiled by the Swift space mission and ground based observatories. Astrophysical neutrinos with the highest energy are detected by the IceCube telescope. Hot and Warm sports, anisotropy of ultra-high energy cosmic rays, are found by the Telescope Array and Pierre Auger observatories, respectively. The spectral break in cosmic rays around 200 GeV is discovered and verified for all elements of cosmic rays, which requires a completely different paradigm in cosmic ray propagation. Combining all of those information allows us to learn the structure and evolution of the universe including thermal and non-thermal astrophysical sources, their spatial distributions, time evolutions and properties. Here we overview a few topics particularly emphasizing GRBs, as sources of multi-messenger astrophysics, in connection to GWs, neutrinos, and cosmic rays. Finally we introduce our space experiments on GRBs and cosmic rays for those physics targets.

Nitrogen-doped carbon-coated and graphene oxide-wrapped Fe3O4 nanoparticles were prepared using the electrostatic force between polyethyleneimine-functionalized Fe3O4 nanoparticles and graphene oxide layers, followed by annealing in an N2 atmosphere (Fe3O4@NCG). The electrochemical performance of Fe3O4@NCG was superior to that of graphene oxide- or reduced graphene oxide-wrapped Fe3O4 nanoparticles and carbon-coated Fe3O4 nanoparticles. Fe3O4@NCG exhibited stable specific capacity of ∼895 mAh g−1 after 350 cycles over the voltage range 0.001–3.0 V vs. Li/Li+. The superior performance of Fe3O4@NCG was attributed to the presence of a nitrogen-doped carbon layer and networks of reduced graphene oxide. The chemical route-derived Fe3O4@NCG may be a promising anode material for high-performance lithium-ion batteries.

Flake shaped particles of grain-oriented Fe80Ga20 and Fe73Ga27 alloys were prepared using a high-energy wet ball-milling process. The surface of flakes produced were predominantly parallel to the (1 0 0) crystallographic plane in flakes. These flakes possess two in-plane 〈1 0 0〉 easy axes of magnetization, which enhances magnetostrictive performance and sensitivity for use in composite materials. The deformation mechanism leading to formation of (1 0 0) grain-oriented flakes is associated with small angel crystal reorientations along slip lines similar to what occurs during rolling. Data are presented on the in-plane magnetic properties of these flakes, which were characterized using field-dependent magnetization measurements. The epoxy-bonded composites with the particle alignment exhibited high magnetostriction values of ∼103 ppm.

Accurate atomistic models for metal/oxide interfaces play a pivotal role in determining copper-based interfacial processes, ranging from electronic circuitry wirings to chemical catalysis. The “29” and “44” surfaces represent two of the most classical embryonic oxides on Cu(111). Although many attempts have been made to offer detailed atomistic models of these surface oxides, their atomic structures remain elusive. Here, we address this open question via ab initio STM simulations, where the functionalized-metal tips are explicitly included, and they are corroborated by STM experiments. We find that the fine structures of STM images of the “29” and “44” surfaces are correctly captured with STM theories going beyond the Tersoff-Hamann approximation only. Furthermore, we elucidate a complete atomistic model for the larger “44” surface, completing the picture of early oxidation on copper.

Li+ intercalates into a pure face-centered-cubic (fcc) C60 structure instead of being adsorbed on a single C60 molecule. This hinders the excess storage of Li ions in Li-ion batteries, thereby limiting their applications. However, the associated electrochemical processes and mechanisms have not been investigated owing to the low electrochemical reactivity and poor crystallinity of the C60 powder. Herein, a facile method for synthesizing pure fcc C60 nanoparticles with uniform morphology and superior electrochemical performance in both half- and full-cells is demonstrated using a 1 m LiPF6 solution in ethylene carbonate/diethyl carbonate (1:1 vol%) with 10% fluoroethylene carbonate. The specific capacity of the C60 nanoparticles during the second discharge reaches ≈750 mAh g-1 at 0.1 A g-1 , approximately twice that of graphite. Moreover, by applying in situ X-ray diffraction, high-resolution transmission electron microscopy, and first-principles calculations, an abnormally high Li storage in a crystalline C60 structure is proposed based on the vacant sites among the C60 molecules, Li clusters at different sites, and structural changes during the discharge/charge process. The fcc of C60 transforms tetragonal via orthorhombic Lix C60 and back to the cubic phase during discharge. The presented results will facilitate the development of novel fullerene-based anode materials for Li-ion batteries.

By combining high-throughput experiments and first-principles calculations based on the DFT-ACBN0 approach, we have investigated the energy band gap of Sr-, Pb-, and Bi-substituted BaSnO3 over wide concentration ranges. We show that the band gap energy can be tuned from 3 to 4 eV by chemical substitution. Our work indicates the importance of considering the mixed-valence nature and clustering effects upon substitution of BaSnO3 with Pb and Bi. Starting from the band gap of ∼3.4 eV for pure BaSnO3, we find that Pb substitution changes the gap in a nonmonotonic fashion, reducing it by as much as 0.3 eV. Bi substitution provides a monotonic reduction but introduces electronic states into the energy gap due to Bi clustering. Our findings provide new insight into the ubiquitous phenomena of chemical substitutions in perovskite semiconductors with mixed-valence cations that underpin their physical properties.

Magnetic oxide semiconductors with wide band gaps have promising spintronic applications, especially in the case of magneto-optic devices. Co-doped ZnO (ZnCoO) has been considered for these applications, but the origin of its ferromagnetism has been controversial for several decades and no substantial progress for a practical application has been made to date. In this paper, we present direct evidence of hydrogen-mediated ferromagnetism and spin polarization in the conduction band of ZnCoO. Electron density mapping reveals the formation of Co–H–Co, in agreement with theoretical predictions. Electron spin resonance measurement elucidates the ferromagnetic nature of ZnCoO by the formation of Co–H–Co. We provide evidence from magnetic circular dichroism measurements supporting the hypothesis that Co–H–Co contributes to the spin polarization of the conduction band of hydrogen-doped ZnCoO.

We prepared single-crystal Si nanoparticles (Si NPs) ∼50 nm in diameter using a laser photopyrolysis technique and formed a nitrogen-doped carbon layer on them using pyrrole and FeCl 3 to increase the cycle stability of the Si anodes during volume expansion and contraction. The surface chemical bonding states of the nitrogen-doped carbon-coated Si NPs were investigated. The specific capacity and capacity retention of the sample with 1 g of FeCl 3 were the highest at approximately 967.1 mAh g −1 and 87.3% after 300 cycles at 1 C, respectively. The diffusion coefficient of Li ions after 1000 test cycles was 9.64 × 10 −8 cm 2 s -1 . The higher cycling stability of the Si@NC NPs could be attributed to the nitrogen-doped carbon layers, which provided an efficient transport pathway for the electrons.

Our previous studies revealed that co-transplantation of bone marrow stem cells (BMSCs) and adipose-derived stem cells (ADSCs) can enhance bone regeneration and angiogenesis. However, it is unclear which genes are involved in the regulation of osteogenesis and/or angiogenesis during the co-culturing of BMSCs and ADSCs. The expression patterns of genes associated with osteogenesis and/or angiogenesis were analyzed in osteogenesis-induced BMSCs and ADSCs using an oligonucleotide microarray. Significant difference in the expression patterns of several genes were identified from hierarchical clustering and analyzed on co-cultured BMSCs and ADSCs. Angiopoietin-2 (ANGPT2) and activin receptor-like kinase-1 were significantly down-regulated in co-culture than culture of either BMSCs or ADSCs, while fibroblast growth factor-9 was significantly up-regulated in co-culture. The effect of ANGPT2 in osteogenesis-induced BMSCs was validated using recombinant protein and siRNA of ANGPT2. Treatment of the ANGPT2 protein significantly increased the expressions of osteogenic makers and the intensity of Alizarin red-S staining in BMSCs. Down-regulation of ANGPT2 significantly decreased the expression of osteogenic makers. The treatment of ANGPT2 protein to BMSCs induced significantly increased tube formation in Transwell-co-cultured human umbilical vein endothelial cells (HUVECs) compared with untreated control. ANGPT2 siRNA transfection showed the opposite effects. These results suggest that the treatment of ANGPT2 in BMSCs increase osteogenesis and angiogenesis in vitro, and that the enhancement of osteogenesis and angiogenesis in the co-cultured BMSCs and ADSCs seems to be mediated by a mechanism that makes the activation of ANGPT2 unnecessary. These observations provide the first evidence for positive regulation of osteogenesis by ANGPT2 in vitro. J. Cell. Biochem. 118: 2896–2908, 2017. © 2017 Wiley Periodicals, Inc.

We synthesized polycrystalline Ti 2 Nb 10 O 29 nanofibers (NFs) via a simple post-annealing process of as-electrospun polymeric NFs as an anode material for Li-ion batteries (LIBs). During the first discharge/charge process, the Ti 2 Nb 10 O 29 NFs annealed at 900 °C exhibited insertion/extraction capacities of up to 344 and 304 mAh g −1 , corresponding to 19.1 and 16.7 mol Li + per formula unit, respectively. This material exhibited excellent rate capability (93 mAh g −1 at 15 A g −1 ) and a higher average diffusion coefficient (D Li = ∼1.5 × 10 −12 cm 2 s −1 ) than Ti 2 Nb 10 O 29 powder (∼6.9 × 10 −13 cm 2 s −1 ). This performance can be attributed to the unique nanostructure of firmly interconnected, highly crystalline Ti 2 Nb 10 O 29 nano-grains, which facilitates the Li + and electron transport. The kinetics obtained from current-voltage curves indicate a mixture of diffusion-limited and capacitive processes. The suggested electro-spinning/post annealing approach can effectively provide a simple route towards high-quality Ti 2 Nb 10 O 29 NF-based anodes for high-performance LIBs.

As potential high-performance anodes for Li-ion batteries (LIBs), hierarchical heteronanostructures consisting of TiNb2O7 nanofibers and ultrathin MoS2 nanosheets (TNO@MS HRs) were synthesized by simple electrospinning/hydrothermal processes. With their growth mechanism revealed, the TNO@MS HRs exhibited an entangled structure both for their ionic and electronic conducting pathways, which enabled the synergetic combination of one- and two-dimensional structures to be realized. In the potential range of 0.001–3 V vs Li/Li+, the TNO@MS HR-based LIBs exhibited high capacities of 872 and 740 mAh g–1 after 42 and 200 cycles at a current density of 1 A g–1, respectively, and excellent rate performance of 611 mAh g–1 at 4 A g–1. We believe that the fabrication route of TNO@MS HRs will find visibility for the use of anode electrodes for high capacity LIBs at low cost.

SnO 2 hollow nanofibers (SnO 2 hNFs) are prepared through electrospinning and annealing processes. The polypyrrole layers coated onto the surface of the SnO 2 hNFs are annealed in a nitrogen atmosphere. The nitrogen-doped carbon-coated SnO 2 hNFs (SnO 2 /NC hNFs) are composed of SnO 2 hNFs with a wall thickness of 60–80 nm and a nitrogen-doped carbon layer ∼10 nm thick. The nitrogen content in the carbon layer is approximately 7.95%. Owing to the nitrogen-doped carbon shell layers, the specific reversible capacity of SnO 2 /NC hNFs at a current density of 0.2 A g −1 after 100 cycles is 1648 mAh g −1 , which is 427% higher than that of (386 mAh g −1 ) SnO 2 hNFs. This strategy may open new avenues for the design of other composite architectures as electrode materials in order to achieve high-performance lithium ion batteries.

Multilayer graphene and its stacking order provide both fundamentally intriguing properties and technological engineering applications. Several approaches to control the stacking order have been demonstrated, but a method of precisely controlling the number of layers with desired stacking sequences is still lacking. Here, we propose an approach for controlling the layer thickness and crystallographic stacking sequence of multilayer graphene films at the wafer scale via Cu-Si alloy formation using direct chemical vapour deposition. C atoms are introduced by tuning the ultra-low-limit CH4 concentration to form a SiC layer, reaching one to four graphene layers at the wafer scale after Si sublimation. The crystallographic structure of single-crystalline or uniformly oriented bilayer (AB), trilayer (ABA) and tetralayer (ABCA) graphene are determined via nano-angle-resolved photoemission spectroscopy, which agrees with theoretical calculations, Raman spectroscopy and transport measurements. The present study takes a step towards the layer-controlled growth of graphite and other two-dimensional materials.