Effect of Surface Morphology of Catalysts Nickel Coatings Obtained by Cathodic Arc in the Synthesis of Carbon Nanostructures

In this work carbon nanostructures were synthesized by CVD using nickel films deposited onto silicon substrates by cathodic arc technique. In order to modify the surface morphology of the catalyst, the silicon substrate and the nickel coating were exposed to an Ar ion bombardment generated in a dc glow discharge at room temperature. The surface morphology was examined by atomic force microscopy (AFM). The morphology of the nanotubes and other carbon structures was observed by scanning electron microscopy (FE-SEM) and Transmission Electron Microscopy (TEM).It was found that nanofibers with helical geometry grew on the nickel catalyst deposited onto the silicon substrate without the glow treatment, and carbon nanofiber with a linear geometry grew on the nickel catalyst deposited onto the silicon substrate with the glow treatment. Carbon nanotubes (CNTs) were obtained when the Si substrate and the Ni film were treated with the glow discharge.The CNTs obtained are mostly very thin with an average diameter between 8 and 15 nm, with only a few CNTs with external diameters of up to 60 nm.