| Abstract
| - The growth of single-walled carbon nanotubes (SWNTs) in a chemical vapor deposition (CVD) system is acomplex process. In a typical growth mechanism, the process includes the nucleation stage, the growth stage,and the termination stage. However, most nanotube growth experiments were performed under identical growthconditions for different stages. Here, a two-stage growth process is studied with different growth environmentsat the nucleation stage and growth stage. Priming the catalysts with carbonaceous species is treated as awholly separate process from nanotube growth throughout this work. The optimum conditions for these twostages are found to be different. Conditions that give a high yield of active catalysts will cause impurities tocover the catalysts and halt growth. Similarly, conditions that allow prolonged growth of nanotubes will failto activate all of the catalysts, resulting in low overall yield. The yield of carbon nanotube growth by CVDcan be significantly improved by using a higher carbon feeding rate in the nucleation stage followed bylower carbon feeding rate for continued growth.
|
