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The Effects of Catalyst Preparation Parameters on Carbon Nanotube Growth

Akbarzadeh Pasha, Mohammad | 2010

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 41902 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Vessaghi, Mohammad Ali; Taghavinia, Nima; Shafiekhani, Azizollah
  7. Abstract:
  8. In this study three different methods; hot filament chemical vapor deposition (HFCVD), pulsed laser ablation (PLA) and electrochemical deposition were utilized to prepare catalyst thin films or nanoparticles and thermal chemical vapor deposition (TCVD) was used to grow multiwall carbon nanotubes (MWCNTs). We found that even though the three mentioned techniques have been rarely applied by researchers, they are appropriate and efficient methods to produce catalytic basis for CNT growth. In the TCVD step, liquid petroleum gas (LPG) was applied as carbon source. Although, this gas is a mixture of different hydrocarbons and further contains some sulfur, our results verify that utilizing of LPG which are not mixed with diluter or carrier gas may lead to acceptable growth of CNTs. Annealing process improves the catalytic activity of carbon-metallic thin films which were produced by HFCVD method on Si substrate using a Fe-Cr wire as filament. In addition, we found that the filament temperature at HFCVD stage can be adapted to improve the quality (density and diameter) of the end produced CNTs. By applying the HFCVD method in the presence of plasma, the behavior of produced carbon- metallic thin film was intensively changed. In this case, three different surfaces are activated for CNT growth: top-surface and sub-surface of the carbon-metallic layer and the surface of Si substrate
  9. Keywords:
  10. Carbon Nanotubes ; Catalyst ; Thermal chemical Vapor Deposition ; Nanoparticles ; Liquid Petroleum Gas (LPG)

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