A Raman spectroscopic approach to hydrogen presence in diamond-like carbon using the hydrogen indicator

초록

Diamond-like carbon (DLC) coatings are widely used due to their excellent mechanical and tribological properties; however, reliable evaluation of hydrogen content remains a long-standing challenge. In this study, we experimentally identified a Raman peak at 860 cm-1, referred to as the Hydrogen Indicator (HI) peak, as a qualitative marker of hydrogen incorporation in DLC coatings. Twelve DLC coatings were deposited under varying process conditions, including both hydrogenated and hydrogen-free types, and their bonding structures were analyzed by Raman spectroscopy. The HI peak was consistently observed in all hydrogenated coatings but absent in hydrogen-free ones, clearly distinguishing the two groups. The assignment was validated through consistent observation across twelve DLC coatings with and without hydrogen. These findings demonstrate that the HI peak provides a simple, non-destructive, and robust approach for identifying hydrogen incorporation in DLC coatings, offering significant potential for process control and quality assurance in advanced industrial applications.

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