Atmospheric pressure plasma processes

Carr, J. W., 2001, Atmospheric Pressure Plasma Processing for Damage-Free Optics and Surfaces, Engineering Research Development and Technology -FY-99. Lawrence Livermore National Laboratory, p. 3 1... 

Barreto, M.C., Bonis, J., Thomas, M., Hansel, R., StoU, M., Klages, C.-P, 2012. Reduction of Plasticizer Leaching from PVC by Barrier Coatings Deposited Using DBD Processes at Atmospheric Pressure. Plasma Processes. Polym. 9, 1208-1214. 

Zhu, L., Wang, C., Qiu, Y, 2007. Influence of the amount of absorbed moisture in nylon fibers on atmospheric pressure plasma processing. Surf. Coat. Technol. 201, 7453-7461. 

Girard-Lauriault, P.-L., Desjardins, P., Unger, W.E.S., Lippitz, A., Wertheimer, M.R., 2008. Chemical characterisation of nitrogen-rich plasma-polymer films deposited in dielectric harrier discharges at atmospheric pressure. Plasma Processes Polym. 5, 631—644. 

Atmospheric pressure plasma processes applicable to solar cell processes are therefore dry etching, surface cleaning, etching, and activation. Layer reductions using hydrogen-based atmospheric glow discharge plasmas are also employable. 

Y. Kusano, Atmospheric Pressure Plasma Processing for Polymer Adhesion A Review. The J. of Adhesion 90 (9), 755-77 (2013). 

The probability for tliree-body collisions increases with increasing pressure making the use of an atmospheric pressure plasma desirable. The above process is used worldwide for ozone production for water purification. 

In a cascade process, one incident electron (e ) collides with a neutral atom ((S)) to produce a second electron and an ion ( ). Now there are two electrons and one ion. These two electrons collide with another neutral atom to produce four electrons and three ions. This process continues rapidly and — after about 20 successive sets of collisions — there are millions of electrons and ions. (The mean free path between collisions is very small at atmospheric pressures.) A typical atmospheric-pressure plasma will contain 10 each of electrons and ions per milliliter. Some ions and electrons are lost by recombination to reform neutral atoms, with emission of light. 

Atmospheric pressure plasmas, just like most other plasmas, are generated by a high electric field in a gas volume. The few free electrons which are always present in the gas, due to, for example, cosmic radiation or radioactive decay of certain isotopes, will, after a critical electric field strength has been exceeded, develop an avalanche with ionization and excitation of species. Energy gained by the hot electrons is efficiently transferred and used in the excitation and dissociation of gas molecules. In a nonequilibrium atmospheric pressure plasma, collisions and radiative processes are dominated by energy transfer by stepwise processes and three-body collisions. The dominance of these processes has allowed many... 

The fact that glow discharges have much lower atom number densities than atmospheric pressure plasmas is responsible for the fact that the measurement of fundamental parameters such as electron number densities, electron temperatures, etc. by techniques such as Thomson scattering is much more difficult than in the case of atmospheric pressure plasma discharges, and that this is only now becoming a field of active research. Moreover, the lower collision frequency, which causes large departures from local thermal equilibrium, is responsible for the fact that many more processes are significantly involved in the excitation mechanisms than in the case of atmospheric pressure plasmas. 

One of the critical factors affecting growth rates is the gas-phase temperature which can be reached in a CVD method. A comparison of the various CVD methods to each other demonstratesl that typical linear growth rates correlate positively with estimated gas-phase temperatures (Fig. 1), approaching 1 mm h in atmospheric pressure plasma arc-jet CVD with temperatures around 6000 to 7000 K. The partial pressures of various gas species in typical CVD processes have been calculated as a function of... 

A. Dissociation of molecular oxygen. This process is mostly investigated in strongly nonequilibrium atmospheric-pressure plasma conditions in relation to ozone synthesis (Section 6.5). Here we discuss the characteristics of thermal plasma decomposition of molecular... 

This process in stoichiometric SO2-O2 mixture was investigated in strongly non-eqnilibrinm plasma conditions of a microwave discharge (Baddur and Dandus, 1970), similar to the one mentioned earlier regarding CI2 synthesis. Optimal SO3 synthesis was achieved in these experiments at a pressnre of 10 Torr and a microwave discharge power of 250 W. The high efficiency of the process (6-141) was achieved in atmospheric-pressure plasmas where SO2 was only a small admixture to air (see Section 11.7). 

Neuhaus S, Padeste C, Spencer ND. Functionalization of fluropolymers and polyolefins via grafting of polyelectrolyte brushes from atmospheric-pressure plasma-activated surfaces. Plasma Process Polym 2011 8(6) 512—22. 

Matthews, S.R., McCord, M.G., Bourham, M.A., 2008. Poly(vinyl alcohol) desizing mechanism via atmospheric pressure plasma exposure. Plasma Process. Polym. 2 (9), 702-708. 

Wang, C.X., Qin, Y.P., 2007. Two sided modification of wool fabrics by atmospheric pressure plasma jet Influence of processing parameters on plasma penetration. Surf. Coat. Technol. 201, 6273-6277. 

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