Microstructures and properties of Ag-DLC films prepared by magnetron reactive sputtering

To clarify the effects of silver (Ag) atom content on antibacterial rate and the performance of silver-containing diamond-like carbon (DLC) films, Ag-DLC films were deposited on the glass using magnetron reactive sputtering. The watt of input energy was applied as main process parameter to obtain 1~2 μm thick films. The basic properties such as hardness, electric resistivity and surface roughness were evaluated by hardness tester, 4 points-probe resistivity tester and atomic force microscope (AFM), respectively. The X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectroscope and transmission electron microscope (TEM) were used to examine the microstructures and bonding characteristic and growth morphologies of DLC films. Antibacterial test and contact angle test were undertaken to analyze the antibacterial ability of silver-containing DLC films. The results indicate that, with increasing the input power, the thickness, silver content, I_D/I_G of the films and surface roughness increase, while the hardness and electric resistivity decrease. Antibacterial tests show that, with increasing the input power, the antibacterial ability against E.coli increases. The antibacterial rate of 98% is obtained in the films with 19.77%(atom fraction) silver content when the input power is 200 W.