Selective Growth of Vertically Aligned Single-, Double-, and Triple-Walled Carbon Nanotubes by Radiation-Heated Chemical Vapor Deposition

Abstract

The synthesis of vertically aligned single-walled carbon nanotube (SWCNT), double-walled carbon nanotube (DWCNT), and triple-walled carbon nanotube (TWCNT) films has been achieved by a combination of radiation-heated chemical vapor deposition (RHCVD) and long-throw sputtering. The proportions of specific walled CNTs/as-grown CNTs are as follows: SWCNT/CNT ratio of 87%, DWCNT/CNT ratio of 83%, and TWCNT/CNT ratio of 62%. When the population density of vertically aligned CNTs on a substrate ranges from 1.1 ×109 to 7.1 ×1010 bundles/cm2, the selective growth of graphene walls of CNTs is achieved. As outer diameters and the number of graphene walls of CNTs increase, CNTs grow longer. It is considered that the larger the metallic catalyst diameter, the longer the catalyst lifetime.