Oxygen and nitrogen doped diamond-like carbon thin films: A comparative study

DLC films were deposited on Si substrates using direct ion beam deposition method, followed by investigating the influence of O۲ and N۲ doping on their electrical and structural properties. The films were doped with oxygen and nitrogen under flow rates of ۵ and ۴۰ sccm (standard cubic centimeters per minute). The structure of the films was studied by Raman spectroscopy.  Result showed that by increasing oxygen incorporation, sp۲ content decreases, sp۳ content increases, and the C-C bonding loses its order. As the size of the sp۲-rich cluster increased with N۲ content, the disorder in the DLC samples decreased, leading to a decrease in the FWHM of the G peak. The water contact angle measurement showed that an increase in oxygen flow ratio results in a decrease in contact angle from ۸۲.۹° ± ۲.۱° to ۵۰° ± ۳°. With increasing nitrogen flow rate from ۵ to ۴۰, the contact angle of DLC thin films increased from ۷۸° to ۱۱۰°.

Keywords:

Si substrates , Direct ion beam , DLC films , Raman spectroscopy , water contact angle