Effect of Nitrogen Doping on the Structure and Optical Band Gap of Fluorinated Diamond-Like Carbon Films

Radio-frequency plasma-enhanced chemical vapor deposition technology was applied to the manufacture of nitrogen-doped fluorinated diamondlike carbon films under different nitrogen flow ratios. Atomic force microscopy, Fourier transform infrared absorption spectroscopy, X-ray photoelectron spectroscopy, and ultraviolet-visible spectroscopy were performed to determine the surface morphology, microscopic structure, and optical properties of the films. The spectra of the films were analyzed using a Gaussian peak-fitting algorithm. The films manufactured using this technology were compact and even. As the nitrogen flow ratio increased, the surface roughness of the films decreased. Nitrogen doping was favorable for graphite phase formation in the films. Moreover, the number of sp(2) structures increases. The optical band gap initially increased and then decreased as the nitrogen flow ratio increased slightly. (C) 2013 The Japan Society of Applied Physics