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 sp~2/sp~3-Hybridized Carbon Ratio

摘要

To elucidate the possibility of quantitatively analyzing sp~2-hybridized carbon (sp~2-C) and sp~3-C in carbon materials using total-electron-yield (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 π~*lσ~* 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.