The present monograph is specially focused on flowing plasmas and afterglows devices containing N2. Several plasmas devices are presented and discussed to retain the results of plasmas that produce the highest density of active species.
The plasmas were produced in glow discharges obtained by direct current (DC), high frequency (RF, microwaves) and arcs at low and high gas pressures, in static gas pressure after outgazing at high ultimate pumping (10-8 Torr) and in flowing conditions at low gas pressure (10-3 Torr) to avoid the air impurities.
The most relevant active species in flowing plasmas are the rare gas metastable atoms and the atoms and radicals coming from dissociated molecules (N2, H2, O2, CH4).
There is an interest of rare gas – molecules mixtures to obtain plasmas with high energy electrons in He and long residence times in Ar.
For the first gas laser, the interest was focused on rare gas metastable atoms in He and Ar plasmas. Then for plasma chemistry and surface treatments, the N, H, O and C-atoms, NH and CN radicals were studied in flowing plasma afterglows.
Concerning the surface treatments, the nitriding of TiO2 thin films and the sterilization of medical instruments are focused on the plasmas setups which are producing the most high density of active species.
To control the production of the plasma and afterglow active species, it will be emphasized the optical emission spectroscopy which is a low cost diagnostics well adapted to industrial plasma reactors.
To obtain quantitative measurements of the active species densities, it is reported the diagnostics by optical absorption (resonant absorption for rare gas metastable atoms), by NO titration for N and O – atoms and by laser induced fluorescence (LIF, TALIF) for N, O and H-atoms.
This last sophisticated laser method is of interest to choose the kinetics reactions allowing to interpret the results by the line ratio intensity of the optical emission spectroscopy.
The present monograph is conduced in the order of DC glow discharges, Arc plasmas, RF and then microwave plasmas and afterglows. A comparison of RF and HF flowing plasmas and afterglows is discussed from similar setups in Ajou and Laplace Universities.
For each studied plasma device, results are given on optical spectroscopy including LIF for the measurement of N and H active species densities.
