| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2006: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2005: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
In order to develop the chemical analysis method for the lowZ functional materials using soft x-ray synchrotron radiation, we have studied on the soft x-ray spectroscopy of carbon materials. In this study, we have focused on the following subjects; (1) Spectral database for the finger-print analysis using soft x-ray spectroscopy and (2) Application of the soft x-ray spectroscopy for chemical analysis of industrial carbon materials.
For the development of the spectral database, we have measured soft x-ray emission and absorption spectra in the CK region of various polycyclic aromatic hydrocarbons (PAH) and typical organic compounds at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory (LBNL), and have partially put it up the web-site of our laboratory (http://www.eng.u-hyogo.ac.jp/msc/msc7/). This database will be useful for soft x-ray chemical analysis of graphite-base carbon materials. For the chemical analysis of industrial carbon materials, we have analyzed
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(a) thermal CVD carbon films deposited on Japanese smoked roof tiles, (b) diamond semiconductors, (c) carbon black, and (d) carbon-implanted silicon layers. In the thermal CVD carbon films, we have characterized the defects on the films as rust formed from iron in sintered clay substrates with water. In the diamond semiconductors, we have clearly observed the band-gap structure in the x-ray emission and absorption spectra of boron (B)-doped p-type diamond semiconductors. We have also tired to measure the phosphorus (P)-doped n-type diamond. However, we can not observed the semiconductive band-gap structure, because P atoms can not be sufficiently doped in the measured diamond samples. Heavily P-doped (provably, several thousands ppm) diamond samples will be necessary to investigate the electronic structure of the n-type diamond semiconductors by soft x-ray spectroscopy. In the carbon black, we have found the relation between the pi^*-peak width in the CK-edge x-ray absorption spectra and the primary particle size of carbon black. From the theoretical analysis of the pi^*-peak profile, we can propose a new crystallite model of carbon black; Non-benzenoid rings and hydrogen-terminated edge-carbon atoms should be considered in carbon black crystallites. In the carbon-doped silicon, we have found that the carbon atoms form covalent C-Si bonds in silicon matrix.
In conclusion, we have demonstrated that the soft x-ray spectroscopy using synchrotron radiation is a powerful tool for chemical analysis of low-Z materials, especially carbon material. Less
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