Characterization and optical investigation of diamondlike carbon prepared by electron cyclotron resonance plasma

Diamondlike carbon (DLC) films have been prepared on radio-frequency (rf) biased substrates maintained at low temperature (similar to 60 degrees C) using electron cyclotron resonance CH4-Ar plasma. The structures of the resultant films were characterized by Fourier transform infrared (FTIR), Raman, and ultraviolet/visible (UV/VIS) spectrometry. The studies revealed that the deposited structures were DLC films with sp(3)/sp(2) bond hybridization, extremely high hardness (> 3000 kgf/mm(2)), and high electrical resistivity (up to 10(14) Omega cm), The DLC films deposited on colorless (transparent) polymer plastics were examined to determine visible light transparencies and optical bandgaps. The results indicate that electron cyclotron resonance (ECR) plasma processing with low negative rf bias, low deposition temperature, and suitable CH4/Ar gas composition can form optically visible light transparent and hard protective DLC films on polymer plastic surfaces.