Morphology and structure of diamond-like carbon film induced by picosecond laser ablation

Raman spectroscopy was performed to investigate the laser-induced microscopic structural changes in diamond-like carbon known as tetrahedral amorphous carbon. Coarse laser-induced periodic surface structures (LIPSSs) at the center of the crater and fine LIPSSs at the upper and lower peripheral regions of the ablated crater were formed via laser irradiation. An analysis of the Raman spectra via mapping measurements around the periphery of the crater demonstrated an increase in defect density occurred without morphological or structural changes. In irradiated areas with a higher local fluence, clustering and crystallization of sp 2 occurred. The relationship between the crystalline structural changes and the local fluence was discussed.