Preparation of crystalline C_3N_4 films from methanol and ammonia water using pulsed arc discharge

The preparation of crystalline C_3N_4 films was investigated using a high density pulsed arc discharge plasma at atmospheric pressure and with a low substrate temperature. The direct current pulsed arc discharge plasma was excited using drops of methanol and ammonia water passing between high voltage electrodes. The morphologies and the structure of the specimens were analyzed using scanning electron microscopy, X-ray diffraction (XRD) and Raman spectroscopy. XRD patterns of the films prepared at a substrate temperature of 450℃ suggest that the film is composed of both α-C_3N_4 and β-C_3N_4 crystals, and Raman spectra show distinct peaks consistent with this. When the substrate temperature was increased to 550℃ Raman analysis showed that the deposits were carbon films.