Oxygen doping effect on wettability of diamond-like carbon films

DLC films were deposited on Ge substrates using direct ion beam deposition method, followed by investigating the influence of O _2 doping on their morphological, electrical, and structural properties. The films were doped with oxygen under flow rates of 5, 10, 20, and 40 sccm (standard cubic centimeters per minute). The structure of the films was studied by Raman spectroscopy. Result showed that by increasing oxygen incorporation, sp ^2 content decreases, sp ^3 content increases, and the C-C bonding loses its order. The hydrophilicity of the layers was analyzed by the contact angle measuring experiment. The results showed that by increasing the O _2 flow ratio from 5 to 40 sccm, the percentage of O _2 increases from 1.1 to 3.9%. The water contact angle measurement showed that an increase in oxygen flow ratio results in a decrease in contact angle from 82.9° ± 2.1° to 50° ± 3°