| Budget Amount *help |
¥4,010,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥510,000)
Fiscal Year 2007: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2006: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
Synthesis of low-dimensional nano-carbons by using surface precipitation of dissolved carbon dopants is a novel fabrication method for nano-carbons without an external carbon source (Fujita et al, 2003, JJAP). It is required for us to control the variation of nano-carbons, based on the growth mechanism. The objective of the research is to clarify the growth mechanism on carbon-doped metal substrates by using surface nanocharacterization techniques, establish the method for synthesis and control of nano-carbons, and to explore the novel functionalities and applications. As for the specimens, various carbon-doped metals (mono-crystalline C-Ni (111), poly-crystalline C-Ni, C-Pt, C-Co, etc.) were prepared Carbon doping up to about 0.3 at% was performed by solid-state diffusion in vacuum at the elevated temperature. After polished and cleaned, the samples were heat-treated in UHV to fabricate nano-carbon films on the substrates, which were characterized by scanning probe microscopy (SPM) an
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d scanning Auger microscopy (SAM). In the case of C-Ni (111), it was found that different nanostructures appeared on the surfaces depending on the heat treatments (rapid cooling or gradual cooling).
As for the gradual cooling, we discovered low-dimensional carbon nanostructures such as nanodots, nanowires, nanobelts, nano-crevices, Moire patterns, and superstructures, which were grown on multi-layer graphite terraces. The observations gave us good suggestions to clarify the growth mechanism. The similar carbon nanowires were also discovered on the freshly cleaved surfaces of HOPG (JJAP, 2007). It is understood that nucleation and growth of rolled graphen sheets, or carbon nanowires, may occur at surface defects such as step edges and atomic vacancies, generated by the stress and strain. In the caw of rapid cooling, initial nucleation of nano-carbons and monolayer graphite were observed. As for applications, we have demonstrated the uses for re-usable high-resolution STM tips and for reference materials for AFM tip-shape characterization. We have obtained the similar results for C-doped Co. In the case of a C-doped Pt sample, we have succeeded in the synthesis of monolayer graphene film with large area. Less
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