F. Massines - Academia.edu (original) (raw)

Papers by F. Massines

It was recently shown that homogeneous dielectric barrier discharges can be generated in the medi... more It was recently shown that homogeneous dielectric barrier discharges can be generated in the medium frequency range at atmospheric pressure. The present paper discuss the advantages of the medium frequency range over the low frequency (30 to 300 kHz) and high frequency (3 to 30 MHz) ranges, namely the capability of tuning the secondary emission via the control of the Townsend-like and glow-like modes.

The aim of this work is to develop a new method to coat thermosensitive materials with a nanocomp... more The aim of this work is to develop a new method to coat thermosensitive materials with a nanocomposite thin film. It is based on the coupling of an atmospheric pressure plasma and of an aerosol formed from a suspension of nanoparticules (Nps) in a liquid. The plasma dissociates the liquid molecules to create reactive species which interact with the NPs in the gas bulk or at the surface to make a nanostructured thin film. This method could work in roll to roll configuration and be therefore useful for inline coating of large twodimensional substrates like polymer films. The atmospheric pressure plasma is a low temperature plasma generated in argon at atmospheric pressure by a dielectric barrier discharge i.e. by applying an AC high voltage on electrodes separated by a gas gap and covered by a solid dielectric. It has been developed to create dense thin films by AP-PECVD (Atmospheric PressurePlasma Enhanced Chemical Vapor Deposition). High quality thin films like water or oxygen barri...

Les films de poly-terephthalate d'ethylene (PET) assembles par collage sont utilises pour rea... more Les films de poly-terephthalate d'ethylene (PET) assembles par collage sont utilises pour realiser des ballons stratospheriques destines au transport de charges utiles scientifiques. Afin d'utiliser un adhesif satisfaisant les specifications de ce type d'applications, on peut modifier la surface de ces films par un Traitement plasma avant assemblage. Suite aux resultats presentes lors des JADH'95 qui montraient l'efficacite de la decharge luminescente a la pression atmospherique (DLPA) dans l'helium par rapport a la decharge couronne dans l'air, nous avons cherche a determiner si les differences observees etaient dues au regime de decharge ou a l'atmosphere de traitement. Pour cela nous avons etudie une decharge couronne dans l'helium. L'evaluation de l'efficacite de chacun des traitements a ete faite par des mesures d'angle de contact, d'ESCA et des tests mecaniques sur des assemblages PET-EVA avec anhydride maleique-PET.

Journal of Physics D: Applied Physics, 2016

In this paper, we investigate DBDs in the medium frequency range (MF, 0.3–3 MHz). More precisely,... more In this paper, we investigate DBDs in the medium frequency range (MF, 0.3–3 MHz). More precisely, for a 2 inter-dielectric gap in helium at atmospheric pressure, the frequency is varied from 1.0 to 2.7 MHz. The generated discharge shows similarities with both the low-frequency atmospheric-pressure glow discharge (APGD) and the atmospheric pressure capacitively coupled radio-frequency (CCRF) discharge. In the frequency range under investigation, two diffuse discharge modes can be observed depending on the voltage applied between the electrodes. At low applied voltage, the discharge emissions are barely visible and are concentrated in the center of the gas gap similarly to CCRF discharges in the Omega\Omega Omega mode where the electron density is concentrated in the bulk. Ohmic heating is the main power transfer mechanism. At higher applied voltage, the discharge emissions are 10 times more intense and are closer to the dielectric surfaces similarly to the more common radio-frequency α mode. These two discharge modes can be observed in the same experimental conditions with the amplitude of the applied voltage as sole control parameter. The gas temperature obtained from N2 impurities rotational spectrum increases from room temperature to about 500 K while the power density rises from 10−1 to 101 W cm−3 when the applied voltage is increased. In addition, when the discharge transits back and forth from the Omega\Omega Omega to the α mode, a hysteresis is observed. The transition from the Omega\Omega Omega to the α mode occurs abruptly with a large RMS current increase while the transition from the α to the Omega\Omega Omega mode is rather smooth with no significant discontinuity in the RMS current.

Plasmas and Polymers, 2000

The aim of this paper is to show the possibility to synthesize silicon-based deposits on a polypr... more The aim of this paper is to show the possibility to synthesize silicon-based deposits on a polypropylene substrate, using a glow dielectric barrier discharge at atmospheric pressure, and to correlate the gas phase behavior with the properties of the thin film deposits. The discharge is generated in a mixture of nitrous oxide and silane, diluted in nitrogen. The influence of

Journal of Applied Physics, 1998

The aim of this paper is to confirm the existence of atmospheric pressure dielectric controlled g... more The aim of this paper is to confirm the existence of atmospheric pressure dielectric controlled glow discharge and to describe its main behavior. Electrical measurements, short time exposure photographs, and numerical modeling were used to achieve this task. Experimental observations and numerical simulation are in good agreement. Therefore, the analysis of the calculated space and time variations of the electric field together with the ion and electron densities helps to explain the discharge mechanisms involved, showing the main role played by the electron as well as helium metastable density just before the discharge is turned on.

IEEE Transactions on Plasma Science, 2009

Abstract In this paper, homogeneous and dense silicon-based coatings have been deposited from hex... more Abstract In this paper, homogeneous and dense silicon-based coatings have been deposited from hexamethyldisiloxane (HMDSO: Si 2 O (CH 3) 6) on patterned silicium in a Townsend dielectric barrier discharge operating at atmospheric pressure. A brief ...

The goal of this work is to help in the understanding of the processes which control the transiti... more The goal of this work is to help in the understanding of the processes which control the transition from filamentary dielectric barrier discharge (DBD) to Townsend DBD (also noted APTD for Atmospheric Pressure Townsend Discharge). The approach consists in comparing the influence of the adding of rather similar additives on the stability of the N2 APTD. These additives are O2 and N2O. According to the literature the maximum concentration allowing an APTD is only 400 ppm for O2 [1] when it is more than 1200 ppm for N2O. In order to understand the mechanisms taking place in such processes, it is important to study the chemical kinetic occurring in the gas phase. To do so, Laser-Induced Fluorescence (LIF) has been developed here for the study of dielectric barrier discharges at atmospheric pressure. One photon LIF is used to measure the absolute concentration of NO and Two-photons Absorption LIF (TALIF) is used to measure [N] and [O] in N2/O2 and N2/N2O mixtures. A 0D model allows to determine the dominant reaction leading to N formation in N2. After a description of the electrical behaviour of the discharge in the two gas mixtures, the absolute density of atomic nitrogen N, atomic oxygen O and nitric oxide NO, in their ground state, are reported and discussed to try to understand the influence of reactive gases on DBD.

This work is the first step of a study of antireflecting and passivating properties of Hydrogenat... more This work is the first step of a study of antireflecting and passivating properties of Hydrogenated Silicon Nitride films (SiNx:Hy) made with a new atmospheric pressure PECVD process. Photovoltaic properties are correlated with physico-chemical ones. Films are deposited with a laboratory scale system of Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition (AP-PECVD) using Ar, SiH4 and NH3 gas mixtures. According to experimental parameters such as the ammonia to silane ratio and the substrate temperature, the surface passivation is determined on FZ silicon wafer by photoconductance decay measurements. The evolution during the days following the deposit realization is also studied. The refractive index and the extinction coefficient are determined from ellipsometry measurements. The chemical composition of the SiNx:Hy is studied by Fourier Transformed InfraRed spectroscopy (FTIR), Secondary Ion Mass Spectroscopy (SIMS), X-ray Photoelectron Spectroscopy (XPS), and Elastic Rec...

An experimental study of dielectric barrier discharge operated under a pulsed radiofrequency (RF)... more An experimental study of dielectric barrier discharge operated under a pulsed radiofrequency (RF) regime is presented. Various systems are compared in atmospheric pressure helium. The effect of different power sources and different matching networks on electrical and optical behaviour of the discharge are compared. Results are analysed according to positive and negative feedback. Furthermore, optical diagnostic shows that the region with the most dissipated energy varies with the power sources and the electrode length. Insights are given on the kind of discharges that would be optimal for thin film coating.

The transport of TiO2 nanoparticles (NPs) in cold dielectric barrier discharge at atmospheric pre... more The transport of TiO2 nanoparticles (NPs) in cold dielectric barrier discharge at atmospheric pressure (APDBD) is studied by using a laser light scattering technique. TiO2 nanoparticles are injected in the discharge by means of a nebulizer coupled to a spray chamber which is used to prevent NPs agglomerations to reach the plasma. The influence of both the carrier gas (N2) flow and the type of nebulisation chamber used on the transport of TiO2 NPs is reported in this work. Furthermore, a correlation between diffusion measurements and coverage of TiO2 on the substrate can be found.

Plasma Sources Science and Technology, 2019

This work is a contribution to a better understanding of dual frequency discharge at atmospheric ... more This work is a contribution to a better understanding of dual frequency discharge at atmospheric pressure. Based on experiments and numerical modeling, it is focused on radio frequency (5 MHz)low frequency (50 kHz) plane/plane dielectric barrier discharge in a Penning mixture (Ar-NH3). The discharge is in the α-RF mode, biased by a LF voltage having an amplitude ranging from 0 to 1300 V. When the LF amplitude increases, there is a threshold (around 600 V for a 2 mm gap) from which the light intensity (experiment) and the ionization level (modelling) drastically increase. In this work the physics of the RF-LF DBD below and above this threshold is studied. Depending on the respective RF and LF polarity, the net voltage applied to the gas is alternatively enhanced or reduced which induces an increase or a decrease of the ionization level. In all cases the ion drift to the cathode due to the LF voltage results in an ion loss and a production of secondary electrons. For a LF voltage amplitude lower than 600 V, the ions loss to the cathode is higher than the ions creation related to the secondary electrons. The consequence is a decrease of the plasma density. This density oscillates at a frequency equal to 2LF: it is maximum each time the LF voltage amplitude is equal to 0 and minimum when the LF voltage amplitude is maximum. For a LF voltage amplitude higher than 600 V, when the LF and RF polarity are the same, the secondary electrons emission is high enough to counterbalance the ion loss, to enhance the bulk ionization and the discharge becomes a γ-RF. The gas voltage is controlled by the dielectric

Journal of Applied Physics, 2017

Diffuse dielectric barrier discharges in atmospheric-pressure helium can be sustained over a wide... more Diffuse dielectric barrier discharges in atmospheric-pressure helium can be sustained over a wide range of excitation frequencies (from, but not restricted, 25 kHz to 15 MHz). The aim of the present paper is to identify the specific characteristics of the discharge modes that can be sustained in this frequency range, namely, the atmospheric-pressure Townsend-like discharge (APTD-L) mode, the atmospheric-pressure glow discharge (APGD) mode, the X mode, the hybrid mode, and the RF-a mode. This is achieved experimentally, by measuring the density of helium metastable atoms, which are known to play a driving role on the discharge kinetics. This density is measured by means of two absorption spectroscopy methods, one using a spectral lamp and the other one using a diode laser as a light source. The first one provides the time-averaged atom densities in the singlet He(2 1 S) and triplet He(2 3 S) metastable states, while with the second one we access the timeresolved density of He(2 3 S) atoms. Time-averaged measurements indicate that the He(2 3 S) density is relatively low in the APTD-L, the X and the RF-a modes (<4 Â 10 16 m À3) slightly higher in the APGD mode (2-7 Â 10 16 m À3), and still higher (>1 Â 10 17 m À3) in the hybrid mode. The hybrid mode is exclusively observed for frequencies from 0.2 to 3 MHz. However, time-resolved density measurement shows that at 1 MHz and below, the hybrid mode is not continuously sustained. Instead, the discharge oscillates between the X and the hybrid mode with a switching frequency about the kilohertz. This explains the significantly lower power required to sustain the plasma as compared to above 1 MHz.

Nondestructive Characterization of Materials II, 1987

A polymer can be defined as a large molecule made of a number of repeating units. Actually many n... more A polymer can be defined as a large molecule made of a number of repeating units. Actually many natural organic substances, such as hevea rubber, cellulose, starch, leather, proteins... are polymers. The hypothesis, that these materials are made of very long chains and that they owe their specific properties to this peculiar structure, was first put forth by Kekule in 1877. Since then, the macromolecular theory has been substantiated by its numerous success, both scientific — one of the most exhilarating being the discovery of the double helix structure for the DNA molecule by Crick, Watson and Wilkins (1953) — and industrial, with the advent of totally synthetic polymers which today represent an important portion of industrial materials.

Plasmas and Polymers, 2001

Dielectric barrier discharge (DBD) is the discharge involved in corona treatment, widely used in ... more Dielectric barrier discharge (DBD) is the discharge involved in corona treatment, widely used in industry to increase the wettability or the adhesion of polymer films or fibers. Usually DBD's are filamentary discharges but recently a homogeneous glow DBD has been obtained. The aim of this paper is to compare polypropylene surface transformations realized with filamentary and glow DBD in different

Surface and Coatings Technology, 2005

The aim of this study is to contribute to the understanding of the thin film growth mechanism usi... more The aim of this study is to contribute to the understanding of the thin film growth mechanism using an Atmospheric Pressure Townsendlike Discharge (APTD). Films obtained in dielectric barrier discharges fed with N 2 and small admixtures of hexamethyldisiloxane (HMDSO) and nitrous oxide (N 2 O) as oxidizer gas have been investigated. Results are compared to those obtained with SiH 4 , in similar conditions. The discharge dissipated power and the feed composition ([N 2 O]/[HMDSO] ratio) on film properties have been investigated by means of Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS) and Ellipsometry. The film thickness homogeneity and deposition rate have been measured by means of a profilometer and an ellipsometer at the same time. Then silicon oxide thin film properties obtained with SiH 4 and HMDSO containing APTD are compared. Concerning chemical composition results are similar. In the two cases, a rather low adding of N 2 O allows to get SiO x layer without N and C incorporation. Si-OH bounds are always observed. The relative contribution of homogeneous and heterogeneous growth mechanisms is very dependent on the nature of the precursor. Because of its high reactivity, SiH 4 induces particles formation in the plasma. These particles are efficiently included in the coating, decreasing drastically the layer density. Thin films made with HMDSO are always dense.