Atomic force microscopy and Raman spectroscopy study of the early stages of carbon nanowall growth by dc plasma-enhanced chemical vapor deposition

The early stage of carbon nanowall (CNW) growth on Si substrate by dc plasma-enhanced chemical vapor deposition (PECVD) was investigated by means of atomic force microscopy and Raman spectroscopy. First nanodiamond particles with highly defective graphene layers are shown to be formed over the substrate. Subsequently nanographite grains are formed on the nanodiamond film. The density of nanographite grains increases with increasing deposition time, and they coalesce to form a continuous graphite film. Finally CNWs are shown to grow vertically on the graphite film. Such understanding of the interface layers between the substrate and CNWs will be useful for not only the growth control but also device applications.