Temperature gradient chemical vapor deposition of vertically aligned carbon nanotubes
| Autor: | Seul Ki Youn, Hyung Gyu Park, John Robertson, Baskar Pagadala Gopi, Christos E. Frouzakis, Kenneth B. K. Teo |
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| Rok vydání: | 2013 |
| Předmět: |
Materials science
Mixing (process engineering) Substrate (chemistry) Nanotechnology General Chemistry Chemical vapor deposition Carbon nanotube Thermal treatment law.invention Temperature gradient chemistry.chemical_compound Acetylene chemistry Chemical engineering law Thermal General Materials Science |
| Zdroj: | Carbon. 54:343-352 |
| ISSN: | 0008-6223 |
| DOI: | 10.1016/j.carbon.2012.11.046 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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