Total Electron Yield Soft X-ray Absorption Spectroscopy in the C K Region of the Mixtures of Graphitic Carbons and Diamond for Quantitative Analysis of the sp²/sp³-Hybridized Carbon Ratio

Abstract

To elucidate the possibility of quantitatively analyzing sp 2-hybridized carbon (sp 2-C) and sp 3-C in carbon materials using total-electronyield (TEY) X-ray absorption spectra (XAS) in the C K region, we measured the TEY-XAS of mixtures of multi-walled carbon nanotubes or carbon black as sp 2-C sources and diamond as an sp 3-C source. The measured relationship between the à = à peak intensity ratio in the C K TEY-XAS and the weight (atomic)% of sp 2-C can be successfully explained by the summed TEY of the sp 2-C and sp 3-C components and considering the TEY efficiency of sp 3-C relative to sp 2-C, k. However, the experimentally determined k values show that TEY of the sp 3-C is much smaller than that of sp 2-C by about one order of magnitude, even depending on the chemical form and/or electronic properties of individual carbon components. This suggests that further evaluation of the TEY efficiency is necessary prior to the quantitative sp 2 /sp 3 analysis of carbon materials using the TEY-XAS.

Characteristics of 2-photon ultraviolet laser etching of diamond

“…Two clear features of differing origin are observed. Feature A is associated with sp 2 hybridized carbon [18,21]. The spectrum for freshly cleaved highly oriented pyrolytic graphite (also included in Fig.…”

Evidence for Primal sp2 Defects at the Diamond Surface: Candidates for Electron Trapping and Noise Sources

“…However, 55° (sample/beam angle) nearedge x-ray absorption fine-structure spectroscopy (NEXAFS) at the C1s-edge is well suited to this analysis, as it is equally sensitive to sp 2 and sp 3 hybridised carbon, and the characteristic π* (285 eV) and σ* (>288 eV) resonances are well separated in energy. [31] In fact, the application of this technique to typical diamond surfaces is well known to show the presence of C=C carbon at diamond surfaces, [32] to the extent that samples are typically assumed to either have 'carbon contamination', [33] and/or there is a presumed problem with the normalization technique. [34] Although carbon contamination in the synchrotron beam-line can act to compromise the quantitative reliability of the data collected, there are known effective methods for the removal of these contaminant signals, such as double-normalization, [35] and in-situ heating (>400 °C) for the physical desorption of physisorbed adventitious carbon.…”

Near-Edge X-Ray Absorption Fine Structure Study of Vertically Aligned Carbon Nanotubes Grown by the Surface Decomposition of SiC

“…The C K-edge NEXAFS spectra are quite similar to those of graphite. 13,14,[26][27][28] The sharp peaks at 285.5 and 292.8 eV were derived from the excitons attributed to the dipolar transition of the core level 1s electron into the C-C à and à states in the conduction band, respectively. Two other à transitions from 293 to 299 eV and a broad ( þ ) transition from 301 to 310 eV are also present in the spectra.…”