Direct spectroscopic evidence of self-formed $C60$ inclusions in fullerenelike hydrogenated carbon films

The detection of self-formed $C60$ inclusions in hydrogenated carbon (C:H) with fullerenelike (FL) structure is reported. This material is synthesized by bias-enhanced electron cyclotron resonance chemical vapor deposition at low substrate temperatures $(<120°C)$⁠. The FL structure is identified by high-resolution transmission electron microscopy whereas the presence of $C60$ inclusions is derived from spectral signatures in the $C(1s)$ x-ray absorption near edge structure. The formation of FL-C:H takes place for negative bias voltages higher than $100V$⁠, in parallel with dehydrogenation and drastic improvement of the tribomechanical film properties.