| Atmospheric pressure glow discharge (APGD) represents one of the highlighted research areas in low-temperature plasma physics, primarily because it offers a low cost and chamber-free route for numerous industrial applications. It is well known that the APGD can be used for surface modification, functional film deposition, ozone generation and biological decontamination and so on. In order to achieve a stable and large-gap atmospheric pressure glow discharge, many plasma sources were investigated. Among them, radio frequency (13.56 MHz) discharge has been the most frequently used one. In the capacitively coupled discharge conditions, a desired large gap APGD was achieved.In this paper, the electrical characteristics and the optical emission spectrum of different gas gap Ar APGD between bare electrodes, single barrier and double barrier were studied. The effect of the ratio of O2, N2 and Air mixed in Ar APGD in single barrier and double barrier are emphasized, and got the following conclusions:The differential conductivities was changed from positive to negative with O2 ratio increasing in Ar single barrier RF-DBD, which is different from in N2 mixed Ar, O2 mixed Ar or in double barrier discharge.The Lissajous plot was first proposed to use for the explanation the RF-DBD, and the somewhat blunt vertices of the RF-DBD parallelogram might indicate that the RF-DBD does not have a well-defined charging/discharging transition, and some electrons (called electron seeds) might still exist in the plasma body in each discharge cycle upon the reversal of electric field. The effect of surface temperature of the electrode in Ar+O2 gas mixture with single barrier layer discharge was observed, and it is noticed that the cold electrodes are very important for the glow discharge.As an application, this paper carried out a simple silicon oxide film deposition studies. With HMDSO as the monomer, SiOx thin films can be obtained by using the radio-frequency dielectric barrier discharge at atmospheric pressure.
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