Microstructure and electrochemical properties of nitrogen-doped DLC films deposited by PECVD technique

Nitrogen-doped diamond-like carbon (N-DLC) films were synthesized by glow discharge plasmaenhanced chemical vapor deposition (PECVD) using a hybrid ion beam system. The influence of nitrogenincorporation on the microstructure and electrochemical properties of N-DLC films was investigated byscanning probe microscopy, Raman spectroscopy, X-ray photoemission spectroscopy and cycle voltam-metry. Regardless of the deposition parameters, the surface of all the deposited films is very smooth.Raman spectra show that ID/IG increases from 0.6 to 1.04 with the substrate bias voltage increases. XPSresults identify that carbon is bonded with nitrogen and the substrate bias makes no distinct contributionto the N content in the films, even the N-DLC film at bias of ?550 V has the lowest N–O bonds concen-tration and the highest C–N bonds concentration. The film electrodes show the wide potential windowsrange over 4 V, lower background currents in strong acid media. At the bias of ?550 V, the N-DLC filmelectrode not only exhibits the Ep at 209 mV and Iox /Ired at 0.8778 in K3 Fe(CN)6 solution, respectively, ppbut also illustrates a nearly reversible electrode reaction. The mechanism of electroproperties is discussed in terms of the atomic bond structures and diffusion process.