Carbon nanotubes coated with diamond nanocrystals and silicon carbide by Hot-filament chemical vapor deposition below 200 C substrate temperature

Abstract

Multi-walled carbon nanotubes (MWCNTs) dispersed onto a silicon substrate have been coated with diamond nanocrystals (DNC) and silicon carbide (SiC) from solid carbon and silicon sources exposed to H2 activated by hot filament chemical vapor deposition (HFCVD) at around 190 °C substrate temperature. MWCNT coating by DNC initiates during filament carburization process at 80 °C substrate temperature under conventional HFCVD conditions. The hybrid nanocarbon material was analyzed by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, electron energy loss spectroscopy, selected area electron diffraction, X-ray diffraction and Raman spectroscopy. The structure of the MWCNTs is preserved during coating and the smooth DNC/SiC coating is highly conformal. The average grain size is below 10 nm. The growth mechanism of DNC and SiC onto MWCNT surface is discussed.