Crystalline carbon nitride thin films deposited by microwave plasma chemical vapor deposition

The crystalline carbon nitride thin films have been prepared on Si (100) substrates using microwave plasma chemical vapor deposition technique. The experimental X-ray diffraction pattern of the films prepared contain all the strong peaks of alpha-C3N4 and beta-C3N4, but most of the peaks are overlapped. The films are composed of alpha-C3N4 and beta-C3N4. The N/C atomic ratio is close to the stoichiometric value 1.33. X-ray photoelectron spectroscopic analysis indicated that the binding energies of C 1s and N 1s are 286.43 eV and 399.08 eV respectively. The shifts are attributed to the polarization of C-N bond. Both observed Raman and Fourier transform infrared spectra were compared with the theoretical calculations. The results support the existence of C-N covalent bond in alpha- and beta-C3N4 mixture.