Effects of Oxygen Addition and Treating Distance on Surface Cleaning of ITO Glass by a Non-Equilibrium Nitrogen Atmospheric-Pressure Plasma Jet

Effects of oxygen addition and treating distance on cleaning organic contaminants on stationary and non-stationary (1-9 cm/s) ITO glass surfaces by a parallel-plate nitrogen-based dielectric barrier discharge (DBD) are investigated experimentally; the DBD is driven by a 60 kHz bipolar quasi-pulsed power source. The results show that two regimes of favorable operating condition for improving the hydrophilic property of the surface (reducing the contact angle from 84 degrees to 25-30 degrees) are found. The measured spatial distribution of NO-gamma UV emission, O(3) concentration and OES spectra are shown to strongly correlate with the measured hydrophilic property. At the near jet downstream locations (z < 10 mm), the metastable N(2)(A(3)Sigma(+)(mu)) and photo-induced dissociation of ozone play dominant roles in cleaning the ITO glass surface; while at the far jet downstream locations (z > 10 mm), where the ratio of oxygen to nitrogen is lower, only the long-lived metastable N(2)(A(3)Sigma(+)(mu) ) plays a major role in cleaning the ITO glass surface.