Structural characterization of C3N4 thin films synthesized by microwave plasma chemical vapor deposition

Crystalline carl,on nitride films have been synthesized on Si substrates by microwave plasma chemical vapor deposition technique, using a gas mixture of nitrogen and methane. Scanning electron microscopy shows that the film c onsisted of hexagonal crystalline rods. X-ray diffraction and transmission electron microscopy indicate the films are mainly composed of alpha -and be ta -C-3 N-4 , and these results match more closely with alpha -C3N4 than wi th beta -C3N4 phase. Fourier transform infrared (FTIR) and Raman spectra of carbon nitride were calculated through Hooke's law. The observed FTIR and Raman spectra support the existence of alpha- and beta- C3N4 in the films.