X-ray photoelectron spectroscopy characterization of radio frequency reactively sputtered carbon nitride thin films

Carbon nitride thin films prepared by radio frequency reactive sputtering of graphite in pure nitrogen plasma have been characterized by x-ray photoelectron spectroscopy (XPS) for probing the chemical bonding in the films. The multiple binding energy values obtained for the C 1s and N 1s photoelectrons in the film suggest that both the C and N atoms exhibit at least three types of chemical states, manifestative of different types of the C–N bonding present in the material. The presence of theoretically predicted β-C3N4 phase in our C–N films has been suggested on the basis of XPS and optical data.