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The growth of single-walled carbon nanotubes (SWCNTs) was carried out on SiO2/Si substrates with Pt catalysts at 400, 450, and 700 °C using an alcohol gas source method in a high vacuum, and the grown SWCNTs were characterized by Raman spectroscopy. By optimizing the ethanol pressure, we could grow SWCNTs even at 400 and 450 °C. By reducing the growth temperature, both the diameter and diameter distribution of the SWCNTs were markedly decreased, and the diameters for most of the SNWTs grown at 400 °C were estimated to be below 1 nm from the Raman results. Transmission electron microscopy (TEM) observation showed that the reduction in SWCNT diameter was caused by the decrease in catalyst size with decreasing temperature.

The growth of single-walled carbon nanotubes (SWCNTs) was carried out on SiO2/Si substrates with Pt catalysts between 500 and 700 °C under various ethanol pressures using an alcohol gas source method in a high vacuum and the grown SWCNTs were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. It was found that, irrespective of the growth temperature, the optimal ethanol pressures were 1×10-3–1×10-4 Pa, which were much smaller than those used in the SWCNT growth with Co catalysts. SEM observations showed that the yield of SWCNTs grown with a Pt catalyst under 1×10-3 Pa at 700 °C was similar to that with a Co catalyst under the optimal growth condition, even though the ethanol pressure was fairly lower in the growth with Pt. By optimizing the growth pressure, SWCNTs could be grown even at 500 °C by using a Pt catalyst.

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Growth of single-walled carbon nanotubes (SWNTs) was carried out on SiO 2 /Si substrates with Pt catalysts at 400, 450, and 700• C under various ethanol pressures using an alcohol gas source method in a high vacuum, and the grown SWNTs were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. Irrespective of the growth temperature, both G band and RBM peaks were observed in the Raman spectra under the optimal ethanol pressure (∼ 1 × 10 −3 Pa), indicating that SWNTs grew below 450• C from Pt. At 400 • C, both average diameter and diameter distribution were drastically reduced, and those were fairly smaller and narrower, compared to those for SWNTs grown with Co.