Reactive atom synthesis and characterization of C3N4 crystalline films

Beta-C3N4 crystalline films have been grown on Si(100) substrates by reactive atom vapour deposition. The lattice parameters of the beta-C3N4 crystalline phase, determined by x-ray diffraction and transmission electron diffraction, respectively, are both in good agreement with the theoretically predicted beta-C3N4 Structure lattice constant. X-ray photoeIectron spectroscopy (XPS), Fourier transform infrared spectroscopy and Raman spectroscopy experiments indicate the existence of single (C-N) and double (C=N) 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 beta-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) implying the existence of C=N bonds. Fourier transform infrared spectroscopy also confirmed the presence of sp(3)- and sp(2)-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. Copyright (C) 1999 John Wiley & Sons, Ltd.