Keywords:carbon nanotube, high temperature growth, etchant
Formed simultaneously with CNTs, amorphous carbon (a-C) adsorbs on the surface of catalysts or growth seeds and blocks the active sites. To remove such by-product, relied on oxidation reaction, kinds of etchants have been employed in the growth procedure. As part of the commoner used etchants, H2O and CO2 have been proved to perform some desired etching effects. In the reports we have presented before, when the growth temperature raised up to 1000℃, part of a-C might not be removed, especially when using ethylene as the carbon source. This result reminded us the importance of etchant participated in growth system. In this project, we tried to figure out the etching ability of CO2 in two-stage growth and made a comparison with H2O. It has been found that, different with the etching capacity of H2O performed at 1000℃, CO2 prefers gentler etching effect with fewer CNTs damages even there got excess injection amount, which presented that the CO2 could be a more efficient and stable etchant in CNTs’ growth at high temperature.