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P: Plasmaphysik
P 25: Staubige Plasmen 2
P 25.6: Vortrag
Mittwoch, 29. März 2006, 16:00–16:15, 1004
The role of atomic hydrogen in dust formation from plasmas in C2H2 — •Olivera Stepanovic, Johannes Berndt, and Jörg Winter — Institut für Experimentalphysik II, Ruhr-Universität Bochum
Although a formation of dust particles is intensively investigated for years and models for the mechanism of the growth process and possible precursors in hydrocarbon plasmas are available in the literature, the chemical picture of the dust formation is still not well understood. Hydrogen, in both forms, as atomic (H) and molecular, appears as an important constituent in hydrocarbon plasmas and plays an important role. Here we present the results about the role of H atoms in the dust formation investigated in a double plasma experiment. The experiment consists of two parts: rf 13.56 MHz acetylene plasma and 144.1 MHz H2 plasma as an additional hydrogen fraction in the precursor gas. The H2 plasma can be operated in the fully recombined mode injecting just the H atoms (and possibly excited H2 molecules) into the acetylene plasma. Under some conditions complete suppress of the dust formation in presence of H atoms is observed. We investigated this phenomenon by laser light scattering and mass spectroscopy. The change in the plasma behaviour and the chemical composition in presence of H atoms are observed. This work was partially supported by the DFG in the frame of SFB 591 and by BMBF in the frame of the project FKZ 13N 8049.