Optical emission spectroscopy in atmospheric pressure dielectric barrier discharges in CF_4/noble gas mixtures - The relation between optical emission and CF_4 decomposition

摘要

Atmospheric pressure nonthermal plasma in Ar/CF_4 mixtures radiates continuous spectra which originate from the CF_4 decomposition. Therefore, the optical emission spectroscopy will be an effective method to monitor the in-situ plasma-assisted CF_4 decomposition process. In this work, we have investigated the electrical and optical characteristics of dielectric barrier discharges in CF_4 diluted by noble gases. In Ar/CF_4 discharges, peculiar orange emission from CF_3 radicals generated by the reaction between metastable Ar atom and CF_4 were observed. By using the relative density of metastable Ar atom estimated from N_2 second positive band, the spatial distribution of CF_4 density along the gas flow direction was obtained.