title: Threshold barrier of carbon nanotube growth.
abstract: A previously overlooked step of carbon nanotube (CNT) growth, incorporating C atoms into the CNT wall through the CNT-catalyst interface, is studied by density functional theory calculations. A significant barrier for incorporating C atoms into the CNT wall (∼2  eV for most used catalysts, Fe, Co, and Ni) is revealed and the incorporation can be the threshold step of CNT growth in most experiments. In addition, the temperature dependent CNT growth rate is calculated and our calculation demonstrates that growing 0.1-1 m long CNTs in 1 h is theoretically possible.
authors: Institute of Textile and Clothing, Hong Kong Polytechnic University, Kowloon, Hong Kong, People's Republic of China.
authors: Qinghong
authors: Q
authors: Yuan
authors: Hong
authors: H
authors: Hu
authors: Feng
authors: F
authors: Ding