Polymerization of solid C under C cluster ion bombardment

Lavrentiev, V.*; Vacik, J.*; Naramoto, Hiroshi*; Narumi, Kazumasa

The structure transformation occurring in fullerene films under bombardment with 50-keV C cluster ions is reported. The Raman spectra of the irradiated C films reveal a new peak rising at 1458 cm with increasing ion fluence. This feature of the Raman spectra suggests linear polymerization of solid C induced by the cluster ion impacts. The aligned C polymeric chains composing about 5-10 fullerene molecules have been distinguished on the film surface after the high-fluence irradiation using atomic force microscopy (AFM). The surface profiling analysis of the irradiated films has revealed pronounced sputtering during the treatment. The obtained results indicate that the C polymerization occurs in a deep layer situated more than 40 nm below the film surface. The deep location of the C polymeric phase indirectly confirms the dominant role of shock waves induced by C-ion bombardment in the detected C phase transformation.