Formation of hydrogenated amorphous carbon films containing fullerene-like structures

Hydrogenated amorphous carbon films containing fullerene-like structures were obtained by magnetron sputtering of a titanium target in methane and argon atmosphere. The microstructure of the film was investigated by transmission electron microscopy and Raman spectra. Additionally, the three stage model proposed by Ferrari and Robertson was used to explain the formation process of fullerene-like structures. The results show that titanium target was covered by a hydrocarbon layer, and the new-produced hydrocarbon layer on titanium target rather than the titanium surface was sputtered during deposition. The product of the sputtering can serve as 'seeds' for the formation of fullerene-like structures. These 'seeds' or nuclei are proposed to be open graphene structures, at the effect of ions bombardment, more defects are introduced and the curved structure arises due to incorporation of odd member rings into the graphene sheets, which resulted in the formation of curved planes with small radii of curvature and closed fullerene-like structure.