Effects of Surface Oxides of SiC on Carbon Nanotube Formation by Surface Decomposition

Abstract

The effects of chemical treatment on carbon nanotube (CNT) formation by surface decomposition of 6H–SiC were investigated. In the case of 6H–SiC cleaned with CH2Cl2, CNTs were formed only on the C-(0001) face. On the other hand, in the case of 6H–SiC etched with HF solution, CNTs were formed on both C-(0001) and Si-(0001) faces. X-ray photoelectron spectroscopy (XPS) analysis detected SiOxCy on the C-(0001) face, and SiO2 and SiOvCw on the Si-(0001) face of SiC cleaned with CH2Cl2. The existence of SiO2 on the SiC surface prevented CNT formation. The length of CNTs on the Si-(0001) face was about 65% of that on the C-(0001) face. The length of CNTs on the C-(0001) face was not affected by chemical treatment. The difference of CNT length between the C and the Si faces originated from the anisotropy of thermal oxidation.