| Budget Amount *help |
¥3,920,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥420,000)
Fiscal Year 2007: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2006: ¥2,100,000 (Direct Cost: ¥2,100,000)
|
|---|
| Research Abstract |
Optical transitions between electronic bands in single-walled carbon nanotubes (SWNTs) shows intense resonant behavior due to spike-like structures in the electronic density of states relating to the one-dimensional nanotube structures. Since the resonance energies depend on the chiralities of SWNT, monochromatic laser light will excite only the SWNTs with the corresponding chirality. Resonant Raman scattering can be observed accompanying such band-to-band resonance, and the chirality can be roughly determined from the combination of the resonance energy and the phonon energy of a radial breathing mode in SWNT. In this study, while a laser light excites the electronic states in SWNTs with specific chirality, resonant Raman scattering is studied by another laser light in order to clarify the processes induced in the SWNTs by the first laser irradiation. As the results, in the most remarkable case, SWNTs are decreased by the infrared pulse laser which excites the second electronic bands in semiconducting SWNTs has been observed in the resonant Raman spectra by the visible laser that has the energy corresponding to the third-band transitions. Some new results about the chirality-selective reduction processes have been obtained, and for example, the threshold IR, laser power, reduction rates, and reduction amounts have been clarified. Although some improvements in the accuracy of the Raman scattering experiments are necessary, the two-laser irradiation method will be promising for the clarification and selection of the chiralities of SWNTs.
|
