Structural modifications of hydrogenated amorphous carbon nitride due to ultraviolet light irradiation and thermal annealing

Abstract Hydrogenated amorphous carbon nitride films have been produced using an electron cyclotron resonance nitrogen plasma with various mixtures of N2 and CH4 gases. The structure of the films and their modifications due to ultraviolet light irradiation and thermal annealing have been investigated. We found that ultraviolet light irradiation decreases CH bonding, increases CC and CN double bonding, and increases the optical gap. The changes in film properties due to ultraviolet light irradiation correlate with the content of nitrogen in the films. In contrast to the effects of ultraviolet light irradiation, thermal annealing increases graphitization of the film. The structural modifications due to nitrogen incorporation, ultraviolet light irradiation and the thermal annealing are explained by a cluster model.