Core-Level Shift of Graphene with Number of Layers Studied by Microphotoelectron Spectroscopy and Electrostatic Force Microscopy

Lin, Chin-Hsiang; Shiu, Hung-Wei; Chang, Lo-Yueh; Chen, Chia-Hao; Chang, C.; Chien, Fan Ching

doi:10.1021/jp503649e

Cited by 12 publications

(11 citation statements)

References 31 publications

(65 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The C 1s XPS spectra, shown in Figure 1b, consist of a single asymmetric component at 284.8 eV, shifted of about 0.4 eV higher than that of the HOPG samples measured in the same setup, in agreement with previous reports. 28,29 After cobalt deposition and prior to any treatment, two additional features at ∼1350 and 1625 cm −1 appear in the Raman spectrum. The peak at 1350 cm −1 is assigned to the D band and is activated due to a single-phonon intervalley process caused by defects in the graphene lattice (edges, vacancies etc.).…”

Section: Resultsmentioning

confidence: 99%

Tuning Morphology and Redox Properties of Cobalt Particles Supported on Oxides by an in between Graphene Layer

Luo

Zafeiratos

2016

J. Phys. Chem. C

View full text Add to dashboard Cite

Introduction of graphene layer in-between a cobalt overlayer and an oxide support is proposed as a simple and efficient method to modify the morphology and redox properties of cobalt in reactive environments. Graphene-covered ZnO or SiO2 substrates were decorated by vapor-deposited Co nanoparticles and studied by spectroscopy and microscopy techniques accompanied by numerical simulations. It is shown that at low temperature graphene improves the dispersion of cobalt as compared to oxide substrates, while upon annealing it provokes particle agglomeration. In 7 mbar of oxygen ambient graphene has a minor effect on the Co oxidation process, however, it ameliorates the reducibility of cobalt oxides under hydrogen. Micro-Raman spectra show that in contact with cobalt single-layer graphene becomes defective, while areas with bilayer graphene or free of cobalt proved to be more stable under the gas treatment.

show abstract

Section: Resultsmentioning

confidence: 99%

Tuning Morphology and Redox Properties of Cobalt Particles Supported on Oxides by an in between Graphene Layer

Luo

Zafeiratos

2016

J. Phys. Chem. C

View full text Add to dashboard Cite

show abstract

“…These components contribute only to ~10% of the total intensity of the C 1s core-level spectrum. The C 1s binding energy of the sp2 component for a free-standing and undoped graphene layer (where the Fermi level is assumed to coincide with the Dirac point) was found to be 284.85 eV [48] with an excitation source of 380 eV. The binding energy correction related to the recoil effect for a kinetic energy of ~0.96 keV is estimated to be 44 meV.…”

Section: Computational Detailsmentioning

confidence: 98%

Origin of weak Fermi level pinning at the graphene/silicon interface

et al. 2020

View full text Add to dashboard Cite

The mechanisms governing the formation of Schottky barriers at graphene/hydrogenpassivated silicon interfaces where the graphene plays the role of a two-dimensional (2D) metal electrode have been investigated by means of x-ray photoemission spectroscopy and density functional theory (DFT) calculations. To control the graphene work function without altering neither the structure nor the band dispersion of graphene we used a method that consists in depositing small amounts of gold forming clusters on the graphene/hydrogenpassivated silicon system under ultra-high vacuum environment. We observe from experimental measurements that the Fermi level is mainly free from pinning at the graphene/hydrogen-silicon interface whereas for a semi-infinite metal on silicon the Fermi level is almost fully pinned. This alleviation of the Fermi level pinning observed with the graphene layer is explained by DFT calculations showing that the graphene and the semiconductor are decoupled and that the metal-induced gap states (MIGS) density at the silicon midgap at the interface is very low (< 5 × 10 10 states/eV/cm 2 ). The important conclusion that stems from the DFT results analysis is that the low MIGS density at the semiconductor midgap is related to the 2D nature of the graphene layer. More precisely, the MIGS density is low owing to the lack of propagating states perpendicular to the graphene layer. This finding brings precious information to understand the mechanisms that govern the

show abstract

“…2 Consequently, local bond strain and electron entrapment take place immediately nearby the broken bonds. The local strain and quantum entrapment densely localizes the charge and energy, which modifies the elemental quantities, such as atomic cohesive energy, 4,27 electro-affinity, 28 Hamiltonian, 29 work function, 30 and Young's modulus. 31 Such electronic densification and entrapment may further rationalize the strong localization premise of Philip Anderson 32 to the undercoordinated systems.…”

Section: Bond Order-length-strength (Bols) Notionmentioning

confidence: 99%

Atomistic bond relaxation, energy entrapment, and electron polarization of the Rb_N and Cs_N clusters (N ≤ 58)

Guo

Wang

et al. 2015

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

We systematically examined the effect of atomic undercoordination on the performance of bonds and electrons of Rb and Cs atomic clusters and their solid skins using a combination of photoelectron spectrometric analysis and density functional theory calculations. Results show that atomic coordination number reduction shortens the bonds by up to 30% for the Rb13 and Cs13 clusters, which densifies the local electrons and entraps their binding energies. Consistency between predictions and observations revealed that the Rb 4p level shifts from 13.654 eV for an isolated atom to a bulk value of 14.940 eV and the Cs 5p level shifts from 10.284 to 11.830 eV upon bulk formation. Such core-electron densification and entrapment polarize the valence charge from the inner to the outermost layer of skins, which perturbs the local Hamiltonian and hence dictates the unusual behavior of the Rb and Cs solid skins and nanocrystals.

show abstract

Core-Level Shift of Graphene with Number of Layers Studied by Microphotoelectron Spectroscopy and Electrostatic Force Microscopy

Cited by 12 publications

References 31 publications

Tuning Morphology and Redox Properties of Cobalt Particles Supported on Oxides by an in between Graphene Layer

Tuning Morphology and Redox Properties of Cobalt Particles Supported on Oxides by an in between Graphene Layer

Origin of weak Fermi level pinning at the graphene/silicon interface

Atomistic bond relaxation, energy entrapment, and electron polarization of the Rb_N and Cs_N clusters (N ≤ 58)

Contact Info

Product

Resources

About

Core-Level Shift of Graphene with Number of Layers Studied by Microphotoelectron Spectroscopy and Electrostatic Force Microscopy

Cited by 12 publications

References 31 publications

Tuning Morphology and Redox Properties of Cobalt Particles Supported on Oxides by an in between Graphene Layer

Tuning Morphology and Redox Properties of Cobalt Particles Supported on Oxides by an in between Graphene Layer

Origin of weak Fermi level pinning at the graphene/silicon interface

Atomistic bond relaxation, energy entrapment, and electron polarization of the RbN and CsN clusters (N ≤ 58)

Contact Info

Product

Resources

About

Atomistic bond relaxation, energy entrapment, and electron polarization of the Rb_N and Cs_N clusters (N ≤ 58)