Experimental study of a glow discharge of CH₂-C1₂

Low-pressure DC plasma discharges sustained in a glow discharge of CH₂-Cl₂ are studied. This plasma was generated at a pressure of 1.0 Torr, power of 20 W and a flow of 12 l/min. The diagnostic has been made by optical emission spectroscopy (OES) using a spectrometer. The principal species observed were: were at 339.61, 358.60 and 377.96 nm for C₂(c'¹Π_g-b¹Π_u); at 392.50 nm for C₃('Π_u-'Σ⁺_g); at 431.42 nm for CH(A²Δ-X²Π); at 778.28 nm for Cl; at 657.80 nm for C+; at 471.90 and 487.30 nm for H₂; at 380.61 nm for CH⁺A'Π-X'Σ) and at 317.73 nm for HCL⁺(A²ΣI-X²Π). In the study, special attention was given to the behavior of material deposition in the electrodes. The time dependence of material deposition in the electrodes was also investigated. When the discharge time of CH₂CL₂ plasma was increased, the mass deposition was increased. It can observe that the mass deposition display an increased behavior until 30 min, and then shows an saturation behavior. Fourier Transform Infrared (FTIR) spectroscopy was applied for the surface analysis. The variations of the size of the thin film may change the subsequent chemical reactions in the gas phase significantly. As the reaction time was increased signal from structural fragment containing chlorine atom were loosed, which can explain the behavior observed in the chlorine signal using emission spectroscopy measurements.