Browse
Submit Data
Databases
API
Help

Dataset Information

25 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Vapor-liquid-solid growth of large-area multilayer hexagonal boron nitride on dielectric substrates.

ABSTRACT: Multilayer hexagonal boron nitride (h-BN) is highly desirable as a dielectric substrate for the fabrication of two-dimensional (2D) electronic and optoelectronic devices. However, the controllable synthesis of multilayer h-BN in large areas is still limited in terms of crystallinity, thickness and stacking order. Here, we report a vapor-liquid-solid growth (VLSG) method to achieve uniform multilayer h-BN by using a molten Fe₈₂B₁₈ alloy and N₂ as reactants. Liquid Fe₈₂B₁₈ not only supplies boron but also continuously dissociates nitrogen atoms from the N₂ vapor to support direct h-BN growth on a sapphire substrate; therefore, the VLSG method delivers high-quality h-BN multilayers with a controllable thickness. Further investigation of the phase evolution of the Fe-B-N system reveals that isothermal segregation dominates the growth of the h-BN. The approach herein demonstrates the feasibility for large-area fabrication of van der Waals 2D materials and heterostructures.

SUBMITTER: Shi Z

PROVIDER: S-EPMC7015929 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Synthesis of large-area multilayer hexagonal boron nitride for high material performance.

Project description:Although hexagonal boron nitride (h-BN) is a good candidate for gate-insulating materials by minimizing interaction from substrate, further applications to electronic devices with available two-dimensional semiconductors continue to be limited by flake size. While monolayer h-BN has been synthesized on Pt and Cu foil using chemical vapour deposition (CVD), multilayer h-BN is still absent. Here we use Fe foil and synthesize large-area multilayer h-BN film by CVD with a borazine precursor. These films reveal strong cathodoluminescence and high mechanical strength (Young's modulus: 1.16 ± 0.1 TPa), reminiscent of formation of high-quality h-BN. The CVD-grown graphene on multilayer h-BN film yields a high carrier mobility of ? 24,000 cm(2) V(-1) s(-1) at room temperature, higher than that (? 13,000 (2) V(-1) s(-1)) with exfoliated h-BN. By placing additional h-BN on a SiO2/Si substrate for a MoS2 (WSe2) field-effect transistor, the doping effect from gate oxide is minimized and furthermore the mobility is improved by four (150) times.

| S-EPMC4639899 | biostudies-other

Synthesis and Characterization of Hexagonal Boron Nitride as a Gate Dielectric.

Project description:Two different growth modes of large-area hexagonal boron nitride (h-BN) film, a conventional chemical vapor deposition (CVD) growth mode and a high-pressure CVD growth mode, were compared as a function of the precursor partial pressure. Conventional self-limited CVD growth was obtained below a critical partial pressure of the borazine precursor, whereas a thick h-BN layer (thicker than a critical thickness of 10?nm) was grown beyond a critical partial pressure. An interesting coincidence of a critical thickness of 10?nm was identified in both the CVD growth behavior and in the breakdown electric field strength and leakage current mechanism, indicating that the electrical properties of the CVD h-BN film depended significantly on the film growth mode and the resultant film quality.

| S-EPMC4960585 | biostudies-literature

Controlled Synthesis of Atomically Layered Hexagonal Boron Nitride via Chemical Vapor Deposition.

Project description:Hexagonal boron nitrite (h-BN) is an attractive material for many applications including electronics as a complement to graphene, anti-oxidation coatings, light emitters, etc. However, the synthesis of high-quality h-BN is still a great challenge. In this work, via controlled chemical vapor deposition, we demonstrate the synthesis of h-BN films with a controlled thickness down to atomic layers. The quality of as-grown h-BN is confirmed by complementary characterizations including high-resolution transition electron microscopy, atomic force microscopy, Raman spectroscopy and X-ray photo-electron spectroscopy. This work will pave the way for production of large-scale and high-quality h-BN and its applications as well.

| S-EPMC6274273 | biostudies-literature

Electron transport of WS2 transistors in a hexagonal boron nitride dielectric environment

Project description:We present the first study of the intrinsic electrical properties of WS2 transistors fabricated with two different dielectric environments WS2 on SiO2 and WS2 on h-BN/SiO2, respectively. A comparative analysis of the electrical characteristics of multiple transistors fabricated from natural and synthetic WS2 with various thicknesses from single- up to four-layers and over a wide temperature range from 300?K down to 4.2?K shows that disorder intrinsic to WS2 is currently the limiting factor of the electrical properties of this material. These results shed light on the role played by extrinsic factors such as charge traps in the oxide dielectric thought to be the cause for the commonly observed small values of charge carrier mobility in transition metal dichalcogenides.

| S-EPMC4021321 | biostudies-literature

Introducing Overlapping Grain Boundaries in Chemical Vapor Deposited Hexagonal Boron Nitride Monolayer Films.

Project description:We demonstrate the growth of overlapping grain boundaries in continuous, polycrystalline hexagonal boron nitride (h-BN) monolayer films via scalable catalytic chemical vapor deposition. Unlike the commonly reported atomically stitched grain boundaries, these overlapping grain boundaries do not consist of defect lines within the monolayer films but are composed of self-sealing bilayer regions of limited width. We characterize this overlapping h-BN grain boundary structure in detail by complementary (scanning) transmission electron microscopy techniques and propose a catalytic growth mechanism linked to the subsurface/bulk of the process catalyst and its boron and nitrogen solubilities. Our data suggest that the overlapping grain boundaries are comparatively resilient against deleterious pinhole formation associated with grain boundary defect lines and thus may reduce detrimental breakdown effects when polycrystalline h-BN monolayer films are used as ultrathin dielectrics, barrier layers, or separation membranes.

| S-EPMC5444048 | biostudies-literature

Enhanced tunnel spin injection into graphene using chemical vapor deposited hexagonal boron nitride.

Project description:The van der Waals heterostructures of two-dimensional (2D) atomic crystals constitute a new paradigm in nanoscience. Hybrid devices of graphene with insulating 2D hexagonal boron nitride (h-BN) have emerged as promising nanoelectronic architectures through demonstrations of ultrahigh electron mobilities and charge-based tunnel transistors. Here, we expand the functional horizon of such 2D materials demonstrating the quantum tunneling of spin polarized electrons through atomic planes of CVD grown h-BN. We report excellent tunneling behavior of h-BN layers together with tunnel spin injection and transport in graphene using ferromagnet/h-BN contacts. Employing h-BN tunnel contacts, we observe enhancements in both spin signal amplitude and lifetime by an order of magnitude. We demonstrate spin transport and precession over micrometer-scale distances with spin lifetime up to 0.46 nanosecond. Our results and complementary magnetoresistance calculations illustrate that CVD h-BN tunnel barrier provides a reliable, reproducible and alternative approach to address the conductivity mismatch problem for spin injection into graphene.

| S-EPMC4143790 | biostudies-literature

Negative Refraction with Superior Transmission in Graphene-Hexagonal Boron Nitride (hBN) Multilayer Hyper Crystal.

Project description:In this article, we have theoretically investigated the performance of graphene-hexagonal Boron Nitride (hBN) multilayer structure (hyper crystal) to demonstrate all angle negative refraction along with superior transmission. hBN, one of the latest natural hyperbolic materials, can be a very strong contender to form a hyper crystal with graphene due to its excellence as a graphene-compatible substrate. Although bare hBN can exhibit negative refraction, the transmission is generally low due to its high reflectivity. Whereas due to graphene's 2D nature and metallic characteristics in the frequency range where hBN behaves as a type-I hyperbolic material, we have found graphene-hBN hyper-crystals to exhibit all angle negative refraction with superior transmission. Interestingly, superior transmission from the whole structure can be fully controlled by the tunability of graphene without hampering the negative refraction originated mainly from hBN. We have also presented an effective medium description of the hyper crystal in the low-k limit and validated the proposed theory analytically and with full wave simulations. Along with the current extensive research on hybridization of graphene plasmon polaritons with (hyperbolic) hBN phonon polaritons, this work might have some substantial impact on this field of research and can be very useful in applications such as hyper-lensing.

| S-EPMC4857181 | biostudies-literature

Precisely aligned graphene grown on hexagonal boron nitride by catalyst free chemical vapor deposition.

Project description:To grow precisely aligned graphene on h-BN without metal catalyst is extremely important, which allows for intriguing physical properties and devices of graphene/h-BN hetero-structure to be studied in a controllable manner. In this report, such hetero-structures were fabricated and investigated by atomic resolution scanning probe microscopy. Moiré patterns are observed and the sensitivity of moiré interferometry proves that the graphene grains can align precisely with the underlying h-BN lattice within an error of less than 0.05°. The occurrence of moiré pattern clearly indicates that the graphene locks into h-BN via van der Waals epitaxy with its interfacial stress greatly released. It is worthy to note that the edges of the graphene grains are primarily oriented along the armchair direction. The field effect mobility in such graphene flakes exceeds 20,000 cm(2)·V(-1)·s(-1) at ambient condition. This work opens the door of atomic engineering of graphene on h-BN, and sheds light on fundamental research as well as electronic applications based on graphene/h-BN hetero-structure.

| S-EPMC3773621 | biostudies-literature

Opening of triangular hole in triangular-shaped chemical vapor deposited hexagonal boron nitride crystal.

Project description:In-plane heterostructure of monolayer hexagonal boron nitride (h-BN) and graphene is of great interest for its tunable bandgap and other unique properties. Here, we reveal a H2-induced etching process to introduce triangular hole in triangular-shaped chemical vapor deposited individual h-BN crystal. In this study, we synthesized regular triangular-shaped h-BN crystals with the sizes around 2-10 ?m on Cu foil by chemical vapor deposition (CVD). The etching behavior of individual h-BN crystal was investigated by annealing at different temperature in an H2:Ar atmosphere. Annealing at 900 °C, etching of h-BN was observed from crystal edges with no visible etching at the center of individual crystals. While, annealing at a temperature ? 950 °C, highly anisotropic etching was observed, where the etched areas were equilateral triangle-shaped with same orientation as that of original h-BN crystal. The etching process and well-defined triangular hole formation can be significant platform to fabricate planar heterostructure with graphene or other two-dimensional (2D) materials.

| S-EPMC4650756 | biostudies-literature

In Situ Observations during Chemical Vapor Deposition of Hexagonal Boron Nitride on Polycrystalline Copper.

Project description:Using a combination of complementary in situ X-ray photoelectron spectroscopy and X-ray diffraction, we study the fundamental mechanisms underlying the chemical vapor deposition (CVD) of hexagonal boron nitride (h-BN) on polycrystalline Cu. The nucleation and growth of h-BN layers is found to occur isothermally, i.e., at constant elevated temperature, on the Cu surface during exposure to borazine. A Cu lattice expansion during borazine exposure and B precipitation from Cu upon cooling highlight that B is incorporated into the Cu bulk, i.e., that growth is not just surface-mediated. On this basis we suggest that B is taken up in the Cu catalyst while N is not (by relative amounts), indicating element-specific feeding mechanisms including the bulk of the catalyst. We further show that oxygen intercalation readily occurs under as-grown h-BN during ambient air exposure, as is common in further processing, and that this negatively affects the stability of h-BN on the catalyst. For extended air exposure Cu oxidation is observed, and upon re-heating in vacuum an oxygen-mediated disintegration of the h-BN film via volatile boron oxides occurs. Importantly, this disintegration is catalyst mediated, i.e., occurs at the catalyst/h-BN interface and depends on the level of oxygen fed to this interface. In turn, however, deliberate feeding of oxygen during h-BN deposition can positively affect control over film morphology. We discuss the implications of these observations in the context of corrosion protection and relate them to challenges in process integration and heterostructure CVD.

| S-EPMC4311958 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data