The effects of nitrogenation on the electrochemical properties of nanocrystalline diamond films

The effect of the nitrogenation on the electrochemical properties of nanocrystalline diamond films produced by microwave plasma CVD in CH4–Ar–H2–N2 gas mixtures was studied systematically, using cyclic voltammetry and electrochemical impedance spectroscopy measurements, for the first time. Differential capacitance, kinetic parameters of reactions in [Fe(CN)6]3-/4-redox system and potential window were found to be sensitive to the nitrogen concentration in the process gas. With its increase (from 0 to 25%), a transition of the NCD film behavior from “poor conductor” to metal-like character takes place. The heavily N-doped nanocrystalline diamond films have satisfactory electrochemical properties to be used as electrodes.