Temperature gradient chemical vapor deposition of vertically aligned carbon nanotubes

We present temperature gradient chemical vapor deposition (TG CVD) for producing vertically aligned (VA-) carbon nanotubes (CNTs). Independent heaters on the gas inlet and catalyst substrate sides of a cold-wall, vertical CVD reactor can modulate the gas temperature gradient to lead to controlled th...

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Bibliographic Details
Published in:Carbon (New York) 2013-04, Vol.54, p.343-352
Main Authors: Youn, Seul Ki, Frouzakis, Christos E., Gopi, Baskar Pagadala, Robertson, John, Teo, Kenneth B.K., Park, Hyung Gyu
Format: Article
Language:English
Subjects:
Acetylene
Alignment
Carbon
Carbon nanotubes
Chemical vapor deposition
Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.)
Cross-disciplinary physics: materials science
rheology
Exact sciences and technology
Heaters
Materials science
Methods of deposition of films and coatings
film growth and epitaxy
Nanoscale materials and structures: fabrication and characterization
Nanotubes
Physics
Precursors
Temperature gradient
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Summary:We present temperature gradient chemical vapor deposition (TG CVD) for producing vertically aligned (VA-) carbon nanotubes (CNTs). Independent heaters on the gas inlet and catalyst substrate sides of a cold-wall, vertical CVD reactor can modulate the gas temperature gradient to lead to controlled thermal histories of acetylene precursor. Our growth results reveal that such a precursor thermal history can play a significant role in the growth and structural features of the resultant VA-CNTs. We find several gas thermal zones particularly important to the VA-CNT growth by evaluating the precursor dwell time in different zones. Thermal treatment of the acetylene precursor at 600–700°C is found crucial for the synthesis of VA-CNTs. When this thermal zone is conjoined in particular with a zone >700°C, efficient growths of single-walled and double-walled VA-CNTs can be achieved. These gas thermal zones can contribute to VA-CNT growths by mixing various secondary hydrocarbons with acetylene, corroborated by the results of our reacting flow simulation. Our findings emphasize the influence of gas-phase reactions on the VA-CNT growth and suggest that our TG CVD approach can be practically utilized to modulate complex gas-phase phenomena for the controlled growth of VA-CNTs.
ISSN:0008-6223
1873-3891
DOI:10.1016/j.carbon.2012.11.046