Berlin 2014 – scientific programme

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P: Fachverband Plasmaphysik

P 21: Plasma Technology II

P 21.3: Talk

Thursday, March 20, 2014, 11:30–11:45, SPA HS201

Carbon micro-crystals and micro-bubbles deposition using filamentary pulsed atmospheric pressure plasma — •Ramasamy Pothiraja, Nikita Bibinov, and Peter Awakowicz — Institute for Electrical Engineering and Plasma Technology, Ruhr-University Bochum, 44801 Bochum, Germany.

Thin plasma filaments are produced by propagation of ionization waves from spike-shaped electrode in quartz tube in argon/methane gas mixture at atmospheric pressure. Position of touching point of filaments on substrate surface can be controlled in our experiment by variations of substrate configuration and position on planar grounded electrode. Filament end-point on substrate surface is positioned in argon/hydrocarbon flow as well as in ambient air. Duration of plasma filament contact time on substrate is about one microsecond. Some carbon compounds are formed during this time at the touching points on the substrate surface. Micro-bubbles are produced if filaments touching points are under argon/hydrocarbon flow (away from ambient air). Under air conditions, micro-crystals are formed. Dimension of both compounds is approximately one micrometer (0.5 - 2 micrometer) and corresponds to about 10¹⁰ − 10¹² carbon atoms. Neither diffusion of neutral species nor drift of ions can be a reason for the formation of such big compounds during this short period of filament-substrate interaction. Possibly carbon ions are trapped in a plasma soliton, which are propagated with ionization wave, and transported to the substrate. Mechanism of this transport and characterization of materials formed under different gas conditions will be studied in the future.