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10 June 1996 Deposition and analysis of carbon and silicon clusters generated by laser-induced gas phase reaction
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Proceedings Volume 2802, Laser Chemistry, Biophysics, and Biomedicine; (1996)
Event: International Conference on Coherent and Nonlinear Optics, 1995, St. Petersburg, Russian Federation
Laser driven gas-phase synthesis in a flow reactor was employed for the production of carbon and silicon cluster beams starting from gaseous compounds. It is based on a CO2-laser-induced decomposition of molecular gases containing carbon and silicon, such as C2H2 and SiH4. By introducing a skimmer into the reaction zone, the generated clusters are transferred to the free molecular flow and analyzed with a time-of-flight mass spectrometer. The carbon clusters are characterized by a bimodal distribution. In the region of lower masses C(subscript n clusters were observed up to n equals 19 with the progression n equals 1. In the higher mass fullerenes were observed C60 and C70. Also observed were two types of silicon: clusters with number of atoms up to 12 and also large ones with number of atoms 700 - 1000 which corresponds to nanometer-size. These clusters were deposited on a silicon or sapphire target at room temperature. Micro-Raman spectroscopy techniques were used for characterization of these deposits. In particular for silicon two features in the Raman spectrum were evident: one broad band and a sharp peak which correspondently were attributed to silicon amorphous and crystalline phase and that nanocrystallites deposited on the substrate consist of about 800 atoms (quantum dots with a size of about 3 nm). Thus, the present studies show that the laser-driven nucleation in a flow reactor is a powerful technique to produce fullerenes and silicon quantum dots and other nano- size semiconductors or high-temperature evaporated materials.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
M. Ehbrecht, H. Ferkel, Friedrich Huisken, L. Holz, Yu. N. Polivanov, V. V. Smirnov, and O. M. Stelmakh "Deposition and analysis of carbon and silicon clusters generated by laser-induced gas phase reaction", Proc. SPIE 2802, Laser Chemistry, Biophysics, and Biomedicine, (10 June 1996);

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