Preparation of Carbon Nanowall by Hot-Wire Chemical Vapor Deposition and Effects of Substrate Heating Temperature and Filament Temperature

The preparation of carbon nanowalls (CNWs) by hot-wire chemical vapor deposition (HWCVD) and the effects of substrate heating temperature T-h and filament temperature T-f in this method have been investigated. The CNWs can be prepared by HWCVD using CH4 without H-2 dilution. The wall size obtained from the scanning clectron microscope image and the Raman peak intensity ratio of the G peak to the D peak of the sample changed with T-h and T-f. However, both were maxima at a substrate surface temperature T-s of 730-740 degrees C. which was not the same as T-h, and this result was independent of T-f. The CNWs did not grow at T-f of 1850 degrees C, because the T-f of 1850 degrees C was insufficient for the decomposition of CH4. On the basis of these results. we show that T-h. i.e., T-s is a more important parameter than T-f in the preparation of CNWs by HWCVD.