| Atomic oxygen plays important roles in most case as a reaction partner in both volume and surface processes, such as plasma etching and surface treatment, oxidation of high-temperature superconductor thin films. High-density oxygen atoms are often generated from oxygen molecules by different kinds of electrical discharges. Among various electrical discharge techniques, dielectric barrier discharges is characterized by its low cost and simple setup.In all kinds of oxygen atom-involved applications, it is essential to determine the atomic oxygen density as functions of the operation parameters. Atomic oxygen density can be determined by optical spectrometry techniques and titration method. Among the ordinarily-used optical techniques, vacuum ultraviolet absorption spectroscopy (VUVAS) and two-photon laser-induced fluorescence technique (TPLIF) are able to determine the atomic oxygen in its ground state at certain circumstances. Optical emission spectroscopy (OES), characterized by its simplicity of instrumentation and non-disturbance to the discharge system, can only deal with emissions from excited species. However, the ground state atomic oxygen density can be determined by comparing the optical emission intensity of oxygen atom with that of the actinometer.This paper reported the experimental measurement of O2 dissociation fraction in DBD (dielectric barrier discharges) O2/Ar plasmas using optical emission spectrometry, and the relationships between the intensity at 777nm and gas flow,voltage and pressure are obtained.when the voltage is 7kV and the gas flow of O2 is 1000sccm, the O2 dissociation fraction decreased from 2.8% to 0.7% as the pressure increase from 50Torr to 200Torr. The influences of operational parameters on the production of atomic oxygen were also discussed.
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