Abstract
Al2Ox/Co/Al2Ox multilayer catalysts were employed to grow single-walled carbon nanotubes (SWNTs) by an alcohol gas source method in a high vacuum. Compared to a Co/Al2Ox bilayer catalyst, the SWNT yield was drastically enhanced for growth at 700°C by optimizing the thickness of the Al2Ox top layer, and vertically aligned SWNTs could be grown even at a low ethanol pressure of 1.0×10−1Pa. At a growth temperature of 400°C, the yield enhancement effect decreased and was observed only for a 0.2nm Al thickness of the Al2Ox top layer. The distribution of SWNT diameters at 400°C estimated from the Raman spectra showed that there is little difference between the Co/Al2Ox bilayer and the Al2Ox/Co/Al2Ox multilayer catalysts, in marked contrast to the distribution at 700°C. These results suggest that surface migration of Co atoms is suppressed at 400°C and the size of the Co catalyst particles is kept small even at the growth temperature, which leads to small enhancement effect of the Al2Ox top layers.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.