Atomic Layer Deposition of Buffer Layers for the Growth of Vertically Aligned Carbon Nanotube Arrays

• Published in: Nanoscale research letters 2019-04, Vol.14 (1), p.119-7, Article 119
• Main Authors: Li, Hao-Hao, Yuan, Guang-Jie, Shan, Bo, Zhang, Xiao-Xin, Ma, Hong-Ping, Tian, Ying-Zhong, Lu, Hong-Liang, Liu, Johan
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Applications of Atomic Layer Deposition; Atomic layer deposition; Atomic layer epitaxy; Buffer layers; Carbon; Carbon nanotubes; Catalysis; Catalysts; Chemical synthesis; Chemistry and Materials Science; Deposition; Diffusion layers; Graphene; Growth rate; Heat transfer; Materials Science; Molecular Medicine; Nano Express; Nanochemistry; Nanoparticles; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Nanotubes; Ostwald ripening; Oxide buffer layers; Silicon dioxide; Substrates; Thermal interface materials; Titanium dioxide; Vertically aligned carbon nanotube arrays; Zinc oxide
• ISSN: 1931-7573; 1556-276X; 1556-276X
• DOI: 10.1186/s11671-019-2947-5

Vertically aligned carbon nanotube arrays (VACNTs) show a great potential for various applications, such as thermal interface materials (TIMs). Besides the thermally oxidized SiO 2 , atomic layer deposition (ALD) was also used to synthesize oxide buffer layers before the deposition of the catalyst, such as Al 2 O 3 , TiO 2 , and ZnO. The growth of VACNTs was found to be largely dependent on different oxide buffer layers, which generally prevented the diffusion of the catalyst into the substrate. Among them, the thickest and densest VACNTs could be achieved on Al 2 O 3 , and carbon nanotubes were mostly triple-walled. Besides, the deposition temperature was critical to the growth of VACNTs on Al 2 O 3 , and their growth rate obviously reduced above 650 °C, which might be related to the Ostwald ripening of the catalyst nanoparticles or subsurface diffusion of the catalyst. Furthermore, the VACNTs/graphene composite film was prepared as the thermal interface material. The VACNTs and graphene were proved to be the effective vertical and transverse heat transfer pathways in it, respectively.