An Atomistic Tomographic Study of Oxygen and Hydrogen Atoms and their Molecules in CVD Grown Graphene

Baik, Sung Il; Ma, Lulu; Kim, Yoon Jun; Li, Bo; Liu, Mingjie; Isheim, Dieter; Yakobson, Boris I.; Ajayan, Pulickel M.; Seidman, David N.

doi:10.1002/smll.201501679

Cited by 13 publications

(6 citation statements)

References 53 publications

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“…APT requires the preparation of specialized needle-like sample geometries, a laborious reconstruction process to analyse its results 36 , and its detection efficiency is rather limited 37 . In our case, we are only able to resolve relative mass differences between isotopes of the same element in the same chemical environment.…”

Section: Discussionmentioning

confidence: 99%

Isotope analysis in the transmission electron microscope

et al. 2016

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The Ångström-sized probe of the scanning transmission electron microscope can visualize and collect spectra from single atoms. This can unambiguously resolve the chemical structure of materials, but not their isotopic composition. Here we differentiate between two isotopes of the same element by quantifying how likely the energetic imaging electrons are to eject atoms. First, we measure the displacement probability in graphene grown from either 12C or 13C and describe the process using a quantum mechanical model of lattice vibrations coupled with density functional theory simulations. We then test our spatial resolution in a mixed sample by ejecting individual atoms from nanoscale areas spanning an interface region that is far from atomically sharp, mapping the isotope concentration with a precision better than 20%. Although we use a scanning instrument, our method may be applicable to any atomic resolution transmission electron microscope and to other low-dimensional materials.

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Section: Discussionmentioning

confidence: 99%

Isotope analysis in the transmission electron microscope

et al. 2016

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“…These local compositions match the Z-contrast observations in the STEM-HAADF image, Figure 2a. [43][44][45][46] The important feature of an APT is that it is a spectrometric technique using a microchannel plate (MCP) for detecting ions and measuring their mass-to-charge state ratios (m/n), essentially one ion at a time. The composition of the dark layers was found to be similar to that at the intercolumnar grain boundaries.…”

Section: Tem and Cs-corrected Stem Microstructural And Crystallographmentioning

confidence: 99%

Atomic‐Scale Structural and Chemical Study of Columnar and Multilayer Re–Ni Electrodeposited Thermal Barrier Coating

et al. 2016

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Rhenium alloys exhibit a unique combination of chemical, physical, and mechanical properties that makes them attractive for a variety of applications. Herein, we present atomic-scale structural and atomic part-per-million level three-dimensional (3D) chemical characterization of a Re-Ni coating, combining aberration-corrected scanning transmission electron microscopy (STEM) and atom-probe tomography (APT). A unique combination of a columnar and multilayer structure is formed by singlebath dc-electroplating and is reported here for the first time. Alternating thicker Re-rich and thinner Ni-rich layers support a mechanism in which Ni acts as a reducing agent. The multilayers exhibit hetero-epitaxial growth resulting in high residual shear stresses that lead to formation of corrugated interfaces and an outer layer with mud-cracks. IntroductionRhenium (Re) is a refractory metal with a unique combination of chemical, physical, and mechanical properties that makes it attractive for high-temperature, catalytic, energy, electrical, biomedical, and other applications, in spite of its high cost. [1,2] Interest in electroless deposition [3,4] and electrodeposition [5][6][7][8][9][10][11][12][13][14][15][16] of Re and its alloys has recently emerged. Electroplating of pure Re yields poor deposition results. The addition of salts of the iron-group metals (Ni, Fe, and Co) to the plating bath improves, however, the coating dramatically, allowing deposition of thick layers of the

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“…To fabricate the APT nanotip for 3D atomistic tomography, W x Nb (1– x ) Se 2 was transferred onto a nickel (Ni) foil using the wet-transfer technique. Then, Ni was deposited on W x Nb (1– x ) Se 2 as a protective overlayer and the Ni/W x Nb (1– x ) Se 2 /Ni sandwich structure was chemically analyzed quantitatively utilizing 3D APT . Thin dark W x Nb (1– x ) Se 2 layers were observed between the Ni substrate and Ni protective layers in the SEM micrograph.…”

Section: Resultsmentioning

confidence: 99%

Three-Dimensional Atomistic Tomography of W-Based Alloyed Two-Dimensional Transition Metal Dichalcogenides

Seo

Hwang

Baik

et al. 2018

ACS Appl. Mater. Interfaces

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Increased interest in two-dimensional (2D) materials and heterostructures for use as components of electrical devices has led to the use of an atomically mixed phase between semiconducting and metallic transition metal dichalcogenides that exhibited enhanced interfacial characteristics. To understand the lattice structure and properties of 2D materials on the atomic scale, diverse characterization methods such as Raman spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and X-ray photoemission spectroscopy (XPS) have been applied. However, determination of the exact chemical distribution, which is a critical factor for the interfacial layer, was hindered by limitations of these typical methods. In this work, atom-probe tomography (APT) was introduced for the first time to analyze the three-dimensional atomic distribution and composition variation of the atomic-scale multilayered alloy structure W NbSe. Composition profiles and theoretical calculations for each atom demonstrated the reaction kinetics and stoichiometric inhomogeneity of the W NbSe layer. The role of the intermediate layer was investigated by fabrication of a WSe-based field-effect transistor. Introduction of W NbSe between metallic NbSe and semiconducting WSe layers resulted in improved charge transport with lowering of the contact barrier.

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An Atomistic Tomographic Study of Oxygen and Hydrogen Atoms and their Molecules in CVD Grown Graphene

Cited by 13 publications

References 53 publications

Isotope analysis in the transmission electron microscope

Isotope analysis in the transmission electron microscope

Atomic‐Scale Structural and Chemical Study of Columnar and Multilayer Re–Ni Electrodeposited Thermal Barrier Coating

Three-Dimensional Atomistic Tomography of W-Based Alloyed Two-Dimensional Transition Metal Dichalcogenides

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