Characterization of deposits produced by TEA CO 2 pulsed laser ablation of silicon mono- and dioxide

Abstract

Silicon based deposits were prepared by TEA CO 2 pulsed laser ablation (PLA) of SiO and SiO 2 targets in the atmosphere of selected gases (N 2, He, Ne, Ar, Kr). These deposits possess high specific area of several hundreds m 2 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) Si , silylen Si:, silanon Si O, POL (peroxy linkage) SiOOSi and/or NBOHC (non-bridging oxygen hole center) SiO , POR (peroxy radical) SiOO and dioxysilirane Si(O) 2. In SiO 2 deposits the concentration of silyl Si resp. POR SiOO was determined to be 5.8 × 10 18/g resp. 6.2 × 10 19/g. In SiO deposits the ratio [ Si:]:[ Si ] = (3.1–5.7) × 10 19/g: (5.3–9.8) × 10 19/g was measured. Estimated concentration of [ Si ] in deposits was increased nearly five times in comparison with SiO target. After exposure of the SiO deposits to H 2 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] 2HSi . 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.