Theoretical prediction and synthesis of CSxFy thin films

A new carbon-based compound: CSxFy is reported. Geometry optimizations and energy calculations were performed by density functional theory on graphene-like model systems containing sulfur and fluorine atoms. It is shown that for [S + F] concentrations in the range of 0–10 at. %, short-range ordered structural characteristics similar to graphene pieces containing ring defects are energetically favorable. The modeling predicts that CSxFy exhibiting graphite and fullerene-like characteristics may be synthesized for the mentioned concentration range. Accordingly, CSxFy thin films were synthesized from a graphite solid target and using sulfur hexafluoride as S and F source. In agreement with the theoretical prediction, transmission electron microscopy characterization and selected area electron diffraction confirmed the presence of small ordered clusters with graphitic features in a sample containing 0.4 at. % of S and 3.4 at. % of F.