Low-temperature growth of single-walled carbon nanotube using Al2O3/Pd/Al2O3 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 Al2O3/Pd/Al2O3 multilayer catalysts on SiO2/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.