Low Temperature Synthesis of High-Density Carbon Nanotubes on Insulating Substrate

Ying Xiao; Zubair Ahmed; Zichao Ma; Changjian Zhou; Lining Zhang; Mansun Chan

doi:10.3390/nano9030473

Low Temperature Synthesis of High-Density Carbon Nanotubes on Insulating Substrate

Nanomaterials (Basel). 2019 Mar 21;9(3):473. doi: 10.3390/nano9030473.

Authors

Ying Xiao¹, Zubair Ahmed², Zichao Ma³, Changjian Zhou⁴, Lining Zhang⁵, Mansun Chan⁶

Affiliations

¹ Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China. yxiaoal@ust.hk.
² Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China. zahmed@connect.ust.hk.
³ Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China. zmaaa@connect.ust.hk.
⁴ School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510640, China. zhoucj@scut.edu.cn.
⁵ College of Electronic Science and Technology, Shenzhen University, Shenzhen 518061, China. eelnzhang@szu.edu.cn.
⁶ Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China. mchan@ust.hk.

Abstract

A method to synthesize high-density, vertically-aligned, multi-wall carbon nanotubes (MWCNTs) on an insulating substrate at low temperature using a complementary metal⁻oxide⁻semiconductor (CMOS) compatible process is presented. Two factors are identified to be important in the carbon nanotube (CNT) growth, which are the catalyst design and the substrate material. By using a Ni⁻Al⁻Ni multilayer catalyst film and a ZrO₂ substrate, vertically-aligned CNTs can be synthesized at 340 °C using plasma-enhanced chemical vapor deposition (PECVD). Both the quality and density of the CNTs can be enhanced by increasing the synthesis temperature. The function of the aluminum interlayer in reducing the activation energy of the CNT formation is studied. The nanoparticle sintering and quick accumulation of amorphous carbon covering the catalyst can prematurely stop CNT synthesis. Both effects can be suppressed by using a substrate with a high surface energy such as ZrO₂.

Keywords: CMOS compatible; CNT growth; insulating substrate; low temperature.

Grants and funding

AoE-P04-08/Hong Kong's University Grant Committee via the Area of Excellence project