Synthesis of Vertically Aligned Carbon Nanotubes by dc PECVD

2006 ◽  
Vol 326-328 ◽  
pp. 333-336
Author(s):  
Yun Young Bang ◽  
Tae Jin Je ◽  
Kyung Hyun Whang ◽  
Won Seok Chang

Chemical vapor deposition (CVD) is one of the various synthesis methods that have been employed for CNT growth. In particular, Ren et al reported that large areas of vertically aligned multi-wall carbon nanotubes could be grown using plasma enhanced chemical vapor deposition (PECVD). In the present study, we synthesized aligned CNT arrays using a direct current (dc) PECVD system. The synthesis of CNTs requires a metal catalyst layer, etchant gas, and a carbon source. In this study, the substrate consisted of Si wafers with 10, 30, and 50 nm Ni-sputtered film. Ammonia (NH3) and acetylene (C2H2) were used as the etchant gases and carbon source, respectively. NH3 pretreatment was processed using a flow rate of 180 sccm for 10 min. CNTs were grown on pretreated substrates at 30% C2H2:NH3 flow ratios for 10 min. Carbon nanotubes with diameters ranging from 60 to 80 nanometers and lengths of about 2.7 μm were obtained. Vertical alignment of the carbon nanotubes was observed by FE-SEM.

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Myung Gwan Hahm ◽  
Young-Kyun Kwon ◽  
Ahmed Busnaina ◽  
Yung Joon Jung

Due to their unique one-dimensional nanostructure along with excellent mechanical, electrical, and optical properties, carbon nanotubes (CNTs) become a promising material for diverse nanotechnology applications. However, large-scale and structure controlled synthesis of CNTs still have many difficulties due to the lack of understanding of the fundamental growth mechanism of CNTs, as well as the difficulty of controlling atomic-scale physical and chemical reactions during the nanotube growth process. Especially, controlling the number of graphene wall, diameter, and chirality of CNTs are the most important issues that need to be solved to harness the full potential of CNTs. Here we report the large-scale selective synthesis of vertically aligned single walled carbon nanotubes (SWNTs) and double walled carbon nanotubes (DWNTs) by controlling the size of catalyst nanoparticles in the highly effective oxygen assisted thermal chemical vapor deposition (CVD) process. We also demonstrate a simple but powerful strategy for synthesizing ultrahigh density and diameter selected vertically aligned SWNTs through the precise control of carbon flow during a thermal CVD process.


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