Optical constants of diamond-like carbon films formed by gas cluster ion beam assisted deposition

Abstract

We investigated the refractive index (n) and extinction coefficient (k) of diamond-like carbon (DLC) films formed by gas cluster ion beam (GCIB)-assisted deposition. DLC films are classified into four types based on n and k values (at λ = 2.25 eV). We formed the nonclassified DLC film which has high n (2.4–3.0) and k (0.75–1.0) values. The Raman peak intensity ratio (I D/I G) of this film was 0.601, which corresponds to the value of a-C:H or ta-C:H. The film density was 2.71 g cm−3. The nonclassified DLC film has intermediate properties between a-C:H and ta-C:H with respect to the density and k.