Electric-field-induced diameter control of carbon nanofibers

A novel process is introduced for controlling diameter of carbon nanofibers by changing electric field in a chemical vapor deposition system. It was found that an increase in electric field produced a smaller diameter and narrower diameter distribution of carbon nanofibers, that is, the carbon nanofiber diameter varied in series of 19.2 ± 8.6, 13.8 ± 4.7, and 8.0 ± 2.4 nm corresponding to the electric field of 0, 25,000, and 50,000 V/m, respectively. The theoretical calculation reveals that the mechanism for this change is because Ni catalyst particles become liquid at the reaction temperature and the diameter of the Ni catalyst becomes smaller under the electric field.