Temperature-Dependent Growth of Vertically Aligned Carbon Nanotubes in the Range 800−1100 °C

• Published in: The journal of physical chemistry. B Vol. 106; no. 31; pp. 7614 - 7618
• Main Authors: Lee, Yun Tack, Park, Jeunghee, Choi, Young Sang, Ryu, Hyun, Lee, Hwack Joo
• Format: Journal Article
• Language: English
• Published: American Chemical Society 08-08-2002
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp020488l

We investigated the effect of temperature on the growth rate and structure of carbon nanotubes using scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The carbon nanotubes were grown vertically aligned on iron nanoparticle deposited silicon substrate by thermal chemical vapor deposition of acetylene in the temperature range 800−1100 °C. As the growth temperature increases from 800 to 1100 °C, the average diameter increases from 20 to 150 nm and the growth rate also increases by about 20 times. All carbon nanotubes exhibit a bamboo-like structure over this temperature range. In the carbon nanotubes grown at higher temperature, the thicker compartment layers appear more frequently. The relative amount of crystalline graphitic sheets increases progressively with the growth temperature. The Arrhenius plot provides the activation energy of carbon nanotube growth to be at least 30 kcal/mol. The results indicate that the bulk diffusion of carbons would be an important factor in the growth of carbon nanotubes.