Optical emission spectra (OES) of the plasma during synthesis of carbon nanotubes (CNTs) were in-situ examined for the purpose of understanding the formation mechanism of CNTs. It is observed that simultaneous presence of abundant amount of neutral Fe-atoms and the neutral (or singly-ionized) carbon-atoms in the plasma, but without the induction of carbon clusters, is necessary for growing CNTs. The optimum chamber pressure required is 400 Torr in 100 W microwave powers, which corresponds to 5000 K plasma temperature. The CNTs are presumed to form via gas phase nucleation process and thus obtained CNTs are multi-wall, approximately 30-70 nm in diameter.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Mechanical Engineering
- Materials Chemistry
- Electrical and Electronic Engineering