Swift heavy ion (150 MeV:Ag13Â +) induced structural changes in a-C:H films studied by Raman spectroscopy

A study of the structural changes in amorphous hydrogenated carbon (a-C:H) films induced by swift heavy ion irradiation and laser irradiation is performed. The effect of irradiation on the a-C:H films is found to be dependent on the initial microstructure of the films, i.e., the type of bonding of the carbon atoms and the distribution of hydrogen in the carbon matrix as understood from Raman spectroscopy. The attempt has been made to create a consistent picture of the effect of cluster type, cluster size, network configuration and chemical environment (hydrogen concentration) on Raman spectra. Various possible mechanisms are discussed leading to the changes due to laser and swift heavy ion irradiation, such as change in cluster size, type and C and H erosion, etc., investigated by Raman spectroscopy.