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Carbon nanotube (CNT) growth was carried out on SiO2/Si substrates with a Co catalyst using an alcohol gas source method in an ultra-high vacuum chamber. The resulting CNTs were characterized by scanning electron microscopy (SEM), Raman spectroscopy and transmission electron microscopy (TEM). Reducing the ethanol pressure decreased the optimum growth temperature for maximum yield, enabling single-walled carbon nanotube (SWNT) growth at 400 degrees C. By employing an Al2Ox buffer layer, SWNT yield increased several times, even at 400 degrees C. Under TEM observation, the Co particle size on the Al2Ox layers did not show a significant dependence on the growth temperature between 400 and 700 degrees C. Raman and TEM results confirmed activation of Co particles with larger diameter (>1 nm) by the Al2Ox buffer layer.

Carbon nanotube (CNT) growth in a high vacuum was achieved using alcohol gas source technique. Using Co catalyst, CNTs were grown on SiO 2 /Si substrate below 10 -1 Pa without any carbon decomposition processes. By adjusting the growth pressure and temperature, we successfully grew CNTs under 1×10 -4 Pa. In addition, we achieved CNT growth at 400 o C by reduction of the growth pressure. We also investigated the relation between the growth condition and CNT diameter by Raman spectroscopy and showed that average diameter decreased as the growth pressure was reduced.

Formation process of nanosized cap structures on a thermally treated 6H-SiC(000-1) substrate was investigated using atomic-resolution ultrahigh-vacuum scanning tunneling microscopy (UHV-STM). After formation of clusters of carobon particles 1-2 nanometer in diameter at 1150°C, these nanoparticles merged, forming nanosized cap structures. Hexagonal carbon networks, partly composed of pentagons, were clearly observed on the surface of the cap structures for a sample annealed above 1200 o C. A model for the formation of carbon nanocaps on 6H-SiC(000-1) was proposed. 0901-Ra11-13-Rb11-13.1 Mater. Res. Soc. Symp. Proc. Vol. 901E