Synthesis of single-phase carbon nitride film prepared by hot implantation

High temperature ion implantation (hot implantation) is used to synthesize carbon nitride (CNx) films. Three CNx films are compared by near edge X-ray absorption fine structure (NEXAFS) spectroscopy; one is prepared by room temperature implantation, another is prepared by subsequent annealing, and the other is prepared by hot implantation. The former two films show three comparable discrete peaks in N K-edge NEXAFS spectra, which are assigned to different kinds of local structures at N sites. On the other hand, a single peak grows predominantly in the spectra for the film prepared by hot implantation. Through the polarization dependence analysis of NEXAFS, the dominant peak is assigned to the fullerene-like structure of CNx which consists of pentagons and hexagons. The difference between the CNx films which are synthesized by subsequent annealing and hot implantation is also discussed.