J. Mater. Sci. Technol. ›› 2020, Vol. 54: 105-111.DOI: 10.1016/j.jmst.2020.02.067

• Research Article • Previous Articles     Next Articles

The importance of H2 in the controlled growth of semiconducting single-wall carbon nanotubes

Feng Zhanga,b, Jia Sunc, Yonggang Zhengc, Peng-Xiang Houa,b,*(), Chang Liua,b,*(), Min Chenga,b, Xin Lia,b, Hui-Ming Chenga,d, Zhen Chenc,e   

  1. a Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
    b School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
    c International Research Center for Computational Mechanics, State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116024, China
    d Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China
    e Department of Civil and Environmental Engineering, University of Missouri, Columbia, MO 65211, USA
  • Received:2019-11-04 Revised:2020-02-03 Accepted:2020-02-03 Published:2020-10-01 Online:2020-10-21
  • Contact: Peng-Xiang Hou,Chang Liu

Abstract:

H2 is considered an indispensable component of the atmosphere for the growth of high-quality single-wall carbon nanotubes (SWCNTs) by chemical vapor deposition. However, details of the roles H2 playing are still unclear due to the complex conditions of SWCNT growth. In this study, we elucidate the functions of H2 in the selective growth of semiconducting SWCNTs (s-SWCNTs) by using monodispersed uniform Fe nanoparticles as a catalyst. High-quality s-SWCNTs were synthesized by finely tuning the concentration of H2 and the other growth parameters. Experimental data combined with atomistic simulations indicate that H2 not only adjusts the concentration of the carbon source, but also serves as a mild etchant that selectively removes small carbon caps grown by a perpendicular mode from the Fe nanoparticles. These results provide useful hints for the controlled growth of SWCNTs with a semiconducting or metallic conductivity, and even a specific chirality.

Key words: Single-wall carbon nanotubes, Controlled growth, Semiconducting, Growth mode, H2