Reactive atom synthesis and characterization of C3N4 crystalline films

Abstract

Beta-C3N4 crystalline films have been grown on Si(100) substrates by reactive atom vapour deposition. The lattice parameters of the β-C3N4 crystalline phase, determined by x-ray diffraction and transmission electron diffraction, respectively, are both in good agreement with the theoretically predicted β-C3N4 structure lattice constant. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy and Raman spectroscopy experiments indicate the existence of single and double carbon-nitrogen bonds in the films. The total NC ratio in the films was determined by XPS to be 1.07, with the C-N bonds (which form the β-C3N4 crystalline phase) comprising up to 58% of the film. Raman spectra revealed two resolved peaks at 1224 cm-1 and 1310 cm-1, suggesting the formation of a fourfold coordinated C-N bond, and another two peaks at 1416 cm-1 and 1950 cm-1. Fourier transform infrared spectroscopy also confirmed the presence of sp3- and sp2-hybridized carbon atoms tetrahedrally and hexagonally bonded with nitrogen atoms. The root-mean-square roughness of the film surface was determined by atomic force microscopy to be 18.9 nm.