Bonding modifications in carbon nitride films induced by thermal annealing: An x-ray absorption near edge study

The thermal stability of nonstoichiometric carbon nitride films has been studied by x-ray absorption near edge spectroscopy. Amorphous carbon nitride thin films were annealed in vacuum up to 1150 °C revealing the presence of nitrogen in different bonding configurations. Annealing to 450 °C results in the loss of ∼50% of the nitrogen. The remaining nitrogen is bonded to carbon within a graphitic framework and it evolves into a more stable configuration with increasing temperature without significant N loss up to 820 °C. Beyond this temperature, nitrogen loss occurs without important structural changes.