Growth of graphite film over the tops of vertical carbon nanotubes using Ni/Ti/Si substrate

A substrate with Ni/Ti/Si structure was used to grow vertical carbon nanotubes (CNTs) with a graphite film over CNT tops by thermal chemical vapor deposition with CH4 gas as carbon source. The carbon nanotubes and the substrate were characterized by a field emission scanning electron microscope for the morphologies, a transmission electron microscope for the microstructures, a Raman spectrograph for the crystallinity, and an Auger electron spectrometer for the depth distribution of elements. The result shows that when the thickness ratio of Ni layer to Ti layer in substrate is about 1, a graphite film with relatively good quality can be formed on the CNT tops.