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P: Plasmaphysik
P 25: Staubige Plasmen 2
P 25.2: Talk
Wednesday, March 29, 2006, 15:00–15:15, 1004
Micro-Raman spectroscopy on a-C:H nanoparticles — •Suk-Ho Hong and Jörg Winter — Experimentalphysik II, Ruhr-Universität Bochum, Universitätsstr. 150, Bochum 44780
We present the Raman spectra of amorphous hydrogenated carbon nanoparticles prepared in an Ar-CH4 hydrocarbon plasma. The measured Raman spectra are compared with that of both soft polymer-like and hard diamond-like a-C:H films deposited from pure CH4 plasma. The film properties were studied by Rutherford Backscattering and spectroscopic ellipsometry. It is shown the plasma characteristics are continuously changed from a “presursor-rich” state to a “precursor-depleted” state during the particle formation process. As a result, the net flux of the carbon atoms to the surface of the nanoparticles (growth rate) decreases linearly as a function of time as the nanoparticles are growing up. Also, hydrogen content in nanoparticles increases as a function of nanoparticle size. The particle growth process is then examined by a simple ballistic model. It is found that the volume polymerization process, i.e. the growth of the nanoparticles at a large particle size (≥100 nm) is essentially the same as the surface polymerization process occurring at a surface of a substrate.