Growth and characterisation of polymeric amorphous carbon and carbon nitride films from propane

In this work, we report about the deposition of a-C(N):H films by electron–cyclotron–resonance using propane as a carbon precursor. The films generally present high H contents (up to 61 at.%) and large optical gaps. The maximum N content we obtained is 13 at.%. In nitrogenated films, we observed a strong decrease of the stretching intensity of the infrared spectra of the hydrocarbon (CHn) vibrations, even at very low nitrogen content, the H content being still comparable to that of pure a-C:H. The various phenomena that can lead to such an effect are discussed: (i) different type of hydrogen bonding (CHn and NHn) in presence and in absence of nitrogenation; (ii) weakening of the cross-section of the CHn groups in presence of nitrogen; (iii) large presence of non-bonded hydrogen meaning, with this, either the presence of molecular H2 or unbounded hydrogen. In addition, the residual amount of IR absorption due to C–H vibrations shows that, in a-CN:H, C–H bonded and non-bonded hydrogen does coexist.