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

We carried out single-walled carbon nanotube (SWCNT) growth at 500 and 600 [degrees]C using Al sub(2) O sub(3)/Pd/Al sub(2) O sub(3) multilayer catalysts on SiO sub(2)/Si substrates by the alcohol gas source method. When the ethanol pressures were 1 x 10 super(-4) and 1 x 10 super(-3) Pa, radial-breathing-mode (RBM) peaks and sharp G band peaks appeared in Raman spectra, indicating the growth of SWCNTs even at 500 [degrees]C. When the growth temperature and ethanol pressure were 500 [degrees]C and 1 x 10 super(-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.