Electrochemical characteristics of diamond-like carbon thin films

Diamond-like carbon (DLC) thin films are well known for their outstanding properties like high hardness, low coefficient of friction and good thermal conductivity. Doping of nitrogen (N) onto DLC films can further improve their properties like electrical conductivity, thus making them more suitable than the conventional DLC for many applications. Currently they are widely investigated by researchers in order to optimize their uses in the field of science and engineering. This report is geared towards the potentiality of using nitrogen doped DLC (N-DLC) thin films as film electrodes for heavy metal detection application in the water industry. In this project, nitrogen doped tetrahedral amorphous carbon (ta-C:N) thin films were deposited onto highly conductive silicon wafers using filtered cathodic vacuum arc (FCVA) deposition method with different nitrogen flow rates at 10, 20, 40 and 60 sccm N2. The film structure, surface morphology and electrochemical properties were investigated. The film structure of the films was examined using X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy followed by the surface morphology which was examined using atomic force microscopy (AFM). The electrochemical properties of the films were studied using an electrochemical workstation and an electrochemical cell. XPS results showed that an increase in nitrogen flow rate increases the concentration of nitrogen in the films. Raman spectroscopy revealed that an increase in nitrogen concentration actually increases the amount of sp2 bonds and reduces the amount of sp3 bonds in the films. AFM results illustrated that an increase in nitrogen concentration will increase the surface roughness of the films. Finally, the increase in nitrogen concentration reduces the electrochemical potential window of the N-DLC film electrodes but also increases the sensitivity of the surfaces of the film electrodes to trace heavy metal ions in solution.Bachelor of Engineering (Mechanical Engineering