Evidence for continuous areas of crystalline β–C3N4 in sputter-deposited thin films

Abstract

Carbon nitride films have been deposited using Penning-type opposed target dc reactive sputtering. These films show large (>10 μm2) continuous areas of nanocrystalline material in an amorphous matrix. Electron diffraction shows the nanocrystalline areas to have crystallography consistent with the β–C3N4 phase. Film chemistry analysis using Rutherford backscattering and Raman spectroscopy indicates that only carbon, nitrogen, and trace levels of hydrogen are present. Given this film chemistry and the fit of diffraction data to that predicted for the β–C3N4 structure, it seems likely that the sputtering parameters used have, indeed, produced continuous regions of the elusive β–C3N4 phase.