Initial growth process of carbon nanowalls synthesized by radical injection plasma-enhanced chemical vapor deposition

• Published in: Journal of applied physics Vol. 106; no. 9; pp. 094302 - 094302-6
• Main Authors: Kondo, Shingo, Kawai, Shinji, Takeuchi, Wakana, Yamakawa, Koji, Den, Shoji, Kano, Hiroyuki, Hiramatsu, Mineo, Hori, Masaru
• Format: Journal Article
• Language: English
• Published: American Institute of Physics 01.11.2009
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.3253734

We synthesized carbon nanowalls (CNWs) using radical injection plasma-enhanced chemical vapor deposition. The initial growth process of CNWs was investigated with and without O 2 gas addition to a C 2 F 6 capacitively coupled plasma with H radical injection. In the case of the CNW synthesis without the addition of O 2 gas, scanning electron microscopy (SEM), transmission electron microscopy, x-ray photoelectron spectroscopy (XPS), and Raman spectroscopy revealed that a 10-nm-thick interface layer composed of nanoislands was formed on a Si substrate approximately 1 min prior to CNW formation. In contrast, with O 2 gas addition, SEM and XPS revealed that an interface layer was not formed and that CNWs were grown directly from nanoislands. Moreover, Raman spectroscopy suggested that the interface layer was composed of amorphous carbon and that O 2 gas addition during CNW growth is effective for achieving a high graphitization of CNWs. Therefore, O 2 gas addition has the effect of reducing the amorphicity and disorder of CNWs and controlling CNW nucleation.