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Characterization of deposits produced by TEA CO2 pulsed laser ablation of silicon mono- and dioxide
Authors:Vladislav D?ínek  Karel Vacek  Gleb Yuzhakov  Sergej Naumov
Institution:a Institute of Chemical Process Fundamentals, Academy of Sience of the Czech Republic, Rozvojová 135, 162 05 Praha 6, Suchdol, Czech Republic
b Leibnitz-Institut für Oberflächenmodifizierung e.V. (IOM), Permoserstraße 15, D-04318, Leipzig, Germany
Abstract:Silicon based deposits were prepared by TEA CO2 pulsed laser ablation (PLA) of SiO and SiO2 targets in the atmosphere of selected gases (N2, He, Ne, Ar, Kr). These deposits possess high specific area of several hundreds m2 per gram. Owing to the high specific area, some chemical groups and hydrogen related radical were detected by means of FTIR and EPR analyses and theoretical calculations: silyl (E′ center) triple bond; length of mdashSiradical dot, silylen double bond; length as m-dashSi:, silanon double bond; length as m-dashSidouble bond; length as m-dashO, POL (peroxy linkage) triple bond; length of mdashSiOOSitriple bond; length of mdash and/or NBOHC (non-bridging oxygen hole center) SiOradical dot, POR (peroxy radical) triple bond; length of mdashSiOOradical dot and dioxysilirane double bond; length as m-dashSi(O)2. In SiO2 deposits the concentration of silyl triple bond; length of mdashSiradical dot resp. POR triple bond; length of mdashSiOOradical dot was determined to be 5.8 × 1018/g resp. 6.2 × 1019/g. In SiO deposits the ratio double bond; length as m-dashSi:]:triple bond; length of mdashSiradical dot] = (3.1-5.7) × 1019/g: (5.3-9.8) × 1019/g was measured. Estimated concentration of triple bond; length of mdashSiradical dot] in deposits was increased nearly five times in comparison with SiO target. After exposure of the SiO deposits to H2 EPR doublet with hyperfine splitting of 7.7 mT was observed. The best agreement between calculated theoretical and experimental values was found for the model (HO)3SiO]2HSiradical dot. FTIR measurements and calculations of the silanol theoretical model clusters enabled us to discuss the chemical surroundings of the silanol and to determine the defects in the deposits.
Keywords:D110  E230  L105  S210
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