Low pressure Plasma Enhanced Chemical Vapour Deposition is commonly used to deposit insulators on temperature sensitive substrates. In these processes, the ion bombardment experienced by films during its growth is known to have benefits but also some disadvantages on material properties. In the present paper, we investigate the influence of this bombardment on the structure and the electrical properties of SiO2-like film deposited from oxygen/hexamethyldisiloxane radiofrequency plasma in continuous and pulsed modes. First, we studied the ion kinetics thanks to time-resolved measurements by Langmuir probe. After, we showed the ion bombardment in such plasma controls the OH bond content in deposited films. Finally, we highlight the impressive reduction of fixed charge and interface state densities in films obtained in pulsed mode due to a lower ion bombardment.

A complete PECVD process for the plasma polymerization of miniature proton exchange membranes (PEM) is presented. Styrene and trifluoromethane sulfonic acid are used as plasmagen precursors in a capacitive coupled low pressure discharge. The process is monitored by impedance probe measurements to ensure stability and reproducibility. FTIR analyses show that such membranes are mainly made up of a polystyrene-like matrix with grafted sulfonic acid groups, which proportion is tuneable as a function of the plasma parameters. The best results in term of deposition rate, monomer structure retention and PEM performances are obtained under pulsed plasma conditions, enhancing radical processes compared to continuous plasma. Because of their thinness and cross-linked structure, such membranes exhibit a similar proton conduction ability and a methanol permeability reduced by a factor 150 compared to Nafion$^{\circledR}$. SEM observations show a good compatibility of plasma polymerized membranes whatever the substrate is. Consequently, PECVD process enables their better integration in micro fuel cells compared to conventional spin coating method.

Microplasmas refer to electric discharges created in very small geometries able to operate in DC mode at high pressure without glow to arc transition. The recent and considerable interest in microplasmas is due to their unique properties in term of discharge stability and power loading. A microplasma configuration which has proven to be stable at atmospheric pressure and up to a power density of some 100 kW/cm3 is the Micro Hollow Cathode Discharge (MHCD) developed by Schoenbach and coworkers. MHCDs are created by applying a voltage between two closely spaced hollow electrodes separated by a dielectric layer. The thickness of the dielectric and the diameter of the hole are both on the order of some 100's microns. These MHCDs can be used as plasma cathodes for generating a diffuse discharge between the MHCD cathode and a third positively-biased electrode placed some distance away. This is the so-called Micro Cathode Sustained Discharge (MCSD) configuration, which can be operated as a non self-sustained discharge. In that mode, the MCSD appears as a unique tool for producing, at high pressure, large fluxes of O2(a1Δg) metastable states which cannot be efficiently produced in classical self-sustained discharges. Based on experimental works performed by our group and on modeling studies done by Pitchford and coworkers at Toulouse University, this paper summarizes the properties of the plasmas generated by the MHCD and the MCSD, with an emphasis on the new fascinating opportunities for the production of O2(a1Δg) metastable states by electrical discharges in high pressure rare gas-oxygen mixtures.

Recently, the bactericidal efficiency of a low-pressure plasma process using a pure N2 flowing post discharge was demonstrated [Eur. Phys. J. Appl. Phys. 34, 143 (2006)]. In order to use this process for the decontamination of medical fiberscopes and endoscopes and more generally for the industrial decontamination of hollow bodies, the ability of the nitrogen atoms (which are believed to be the main decontamination agent) to flow in low diameter tubes (between 2 and 8 mm i.d.) without massive destruction is checked. The dependence of the N-atom concentration with the length, the internal diameter and the material of the tubes is studied and quantified. It is shown that the N-atom concentrations measured at the outlet of a polyamide tube of 6 m in length and of a 0.2 m long stainless steel tube are sufficient enough to provide high inactivation levels.

The ion swarm data such as reduced mobilities, diffusion coefficients and reaction rates of N4+ in N2, O2 and dry air (80% N2, 20% O2) have been determined from a Monte Carlo simulation using calculated and measured elastic and inelastic cross sections. The elastic cross sections used have been determined from a semi-classical JWKB approximation based on a rigid core potential model. The inelastic cross section of N4+ in N2 has been deduced from the measured experimental rates whereas for N4+ in O2 the measured inelastic cross sections have been extended to low and high energies by appropriate approximations. Then the cross sections sets have been validated from comparison of calculated and measured ion swarm data. From the cross sections sets obtained in pure N2 and O2, the ion swarm data for N4+ in dry air are then calculated for a large E/N range [1–104] Td. Finally, the influence of N4+ ions on the streamer development was analyzed with a 2D fluid model in the case of dry air at atmospheric pressure for a point-to-plane electrode configuration.

This work is an assessment of recent developments on microwave plasmas at atmospheric pressure and their applications in the field of surface treatment. A special attention is paid to the question of the accuracy of data at high temperature (above 2000 K) and to the non-locality of the energy dissipation in argon and helium plasmas.

This experimental work deals with the exposition of Pinus Pinaster wood samples to a DBD afterglow. Electrical parameters like duty cycle and injected energy in the gas are being varied and the modifications induced by the afterglow on the wood are analysed by several macroscopic and microscopic ways like wettability, XPS analyses and also soaking tests of treated wood in a commercial fungicide solution. Soaking tests show that plasma treatment could enhance the absorption of fungicide into the wood. The wettability results point out that the plasma treatment can inflict on the wood different surface properties, making it hydrophilic or hydrophobic, when varying electrical parameters. XPS analyses reveal several chemical modifications like an increase of the O/C ratio and the presence of carboxyl groups on the surface after plasma treatments.

This paper presents an experimental analysis of the electrical and optical behaviour of positive point-plane corona discharges. The measurements of the instantaneous corona current and the current-voltage characteristics are used with the imagery analyses (CCD and streak camera) to determine the streamer properties such as the streamer morphology and velocity with the primary and secondary streamer developments. These analyses are performed first in synthetic air as a function of operating parameters such the applied voltage. Then the effect of gas mixtures (several proportions of N2, O2 with or without CO2) is analysed. When the gas concentration is varied the discharge morphology, the shape and amplitude of the corona current are significantly affected due to the variation of the gas electronegativity following its composition and concentration.

This paper deals with the optical study of a DBD plasma afterglow generated in nitrogen at atmospheric pressure. Spectroscopic analyses allow identifying active species of this afterglow like molecular species in different energy levels: N2, NO and N2O(1S). By using the NO titration method, the N and O(1S) densities have been estimated to be respectively, 5.9 × 1014 cm−3 and 2 × 1010 cm−3, in an afterglow guided in a quartz tube of 1 cm in diameter.