Abstract

Polycrystalline carbon nitride thin films were deposited on Si (100) substrates by electrolysis of methanol-urea solution at atmospheric pressure and low temperature. The effect of the process parameters, namely deposition time, concentration and applied voltage on growth and bonding state of carbon nitride (CN_x) thin films was studied using Fourier transform infrared (FTIR) spectroscopy, grazing incidence X-ray diffraction (GIXRD) and scanning electron microscope (SEM). The analysis of infrared (IR) spectra revealed that the nitrogen content in the film increased with increasing both urea concentration and the applied voltage. It found from GIXRD patterns that the crystalline structure of carbon nitride films at moderate nitrogen content changed from amorphous phase to polycrystalline α- C₃N₄, and β- C₃N₄ phases. At relatively higher nitrogen content, a new phase of CN_x appeared which increased gradually and became the more predominant phase. SEM images of the films indicated that the surface of the deposited films consists of homogeneous grains of ~0.2 μm and these grains became more closely packed with increasing nitrogen content.

Key words: Carbon nitride, thin films, structure properties.