Optical properties of diamond-like carbon synthesized by plasma immersion ion processing

Hard and transparent diamond-like carbon (DLC) films have been:prepared on low temperature substrates. by using the C2H2-Ar plasma immersion ion proce ssing (PIIP) method. The optical properties of the DLC films deposited on p oly(methylmethacrylate) (PMMA), Silicon wafers, and glass plates were syste matically examined. It was found that careful control of:substrate bias was needed for favorable growth of DLC films with low atomic hydrogen contents , high hardness and mass densities, and excellent optical properties. The r esultant DLC films exhibited a high hardness of above 22 GPa, an optical ga p energy larger than 1.9 eV, a low refractive index of 1.87, and very high: optical transmittance in the visible light range. The study confirmed that C2H2-Ar PIIP with low-negative bias voltages and suitable C2H2/Ar gas rati os: can process optically transparent and hard protective DLC films on PMMA plastics. [S0734-211X(99)02502-03].