Carbon nitride (CNx) films were deposited from acetonitrile at low voltage (150-450 V) through electrodeposition. The films were characterized by atomic force microscopy (AFM), Raman spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. AFM investigations revealed that the grain size was similar to 200 nm and roughness was similar to 10 nm. The films were found to be continuous and close packed. IR spectra revealed existence of strong sp(3), sp(2) type bonding and weak sp type carbon nitrogen bonds and these bonds were found to increase with voltage. The fraction of sp(3)-bonded species in the sample increased in low voltage range and after reaching maximum at 350 V decreased for higher voltages. However, the concentration of sp(2) CN ring structures in the film increased with increasing voltage. Also, the peak width decreased at low voltages reaching a minimum and increased thereafter. It was observed that the voltage dependent increase in the concentration of polymeric type sp(2) CN (chain) structures was much more pronounced than that of graphitic type sp(2) CN (ring) structures. Raman spectra showed the presence of both the D and G bands. The shift in the G band indicated the presence of nitrogen in the film. The WIG ratio was found to increase with the incorporation of nitrogen. Auger electron spectroscopy (AES) showed a clear increase in the nitrogen content with increase in the voltage. The formation of the film could be explained on the basis of dissociation of electrolyte under applied voltage. (c) 2005 Published by Elsevier B.V.