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

Abstract

The preparation of carbon nanowalls (CNWs) by hot-wire chemical vapor deposition (HWCVD) and the effects of substrate heating temperature Th and filament temperature Tf in this method have been investigated. The CNWs can be prepared by HWCVD using CH4 without H2 dilution. The wall size obtained from the scanning electron microscope image and the Raman peak intensity ratio of the G peak to the D peak of the sample changed with Th and Tf. However, both were maxima at a substrate surface temperature Ts of 730–740 °C, which was not the same as Th, and this result was independent of Tf. The CNWs did not grow at Tf of 1850 °C, because the Tf of 1850 °C was insufficient for the decomposition of CH4. On the basis of these results, we show that Th, i.e., Ts is a more important parameter than Tf in the preparation of CNWs by HWCVD.