Low-temperature growth of single-walled carbon nanotube using Al 2 O 3 /Pd/Al 2 O 3 multilayer catalyst by alcohol gas source method at high vacuum

We carried out single-walled carbon nanotube (SWCNT) growth at 500 and 600 °C using Al 2 O 3 /Pd/Al 2 O 3 multilayer catalysts on SiO 2 /Si substrates by the alcohol gas source method. When the ethanol pressures were 1 × 10 −4 and 1 × 10 −3 Pa, radial-breathing-mode (RBM) peaks and sharp G band peaks appeared in Raman spectra, indicating the growth of SWCNTs even at 500 °C. When the growth temperature and ethanol pressure were 500 °C and 1 × 10 −4 Pa, respectively, the growth rate decreased gradually with the growth time, but the SWCNT growth continued for more than 4 h and the diameter distribution changed as the growth proceeded. X-ray photoelectron spectroscopy measurements showed that oxidized Pd catalyst particles were reduced to metallic states after the SWCNT growth started.