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Bousquet, A., Cartry, G. & Granier, A. (2007) Investigation of O-atom kinetics in O-2, CO2, H2O and O-2/HMDSO low pressure radiofrequency pulsed plasmas by time-resolved optical emission spectroscopy. Plasma Sources Sci. Technol. 16 597–605.
Added by: Laurent Cournède (2016-03-10 22:02:29) |
| Type de référence: Article DOI: 10.1088/0963-0252/16/3/020 Numéro d'identification (ISBN etc.): 0963-0252 Clé BibTeX: Bousquet2007 Voir tous les détails bibliographiques  |
Catégories: PCM Mots-clés: cross-sections, deposition, excitation, helicon plasmas, induced fluorescence, oxygen-atoms, recombination, sio2, Surface, tetraethoxysilane Créateurs: Bousquet, Cartry, Granier Collection: Plasma Sources Sci. Technol. |
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In the present paper, O-atom kinetics is investigated in low pressure (around 0.7 Pa) O-2/hexamethyldisiloxane pulsed plasmas by time-resolved optical emission spectroscopy. In order to distinguish direct O-atom excitation by electron impact from dissociative excitation of O-2, CO, CO2 and H2O molecules formed in O-2/HMDSO plasmas, measurements were first carried out in pure O-2, CO2 and H2O plasmas. From these measurements it was concluded that direct O-atom excitation by electron impact was the dominant mechanism and that actinometry could be used to monitor O-atom kinetics provided molecular oxygen dissociative excitation is taken into account. Second, the surface O-atom loss coefficient measured in oxygen pulsed plasmas is in agreement with the literature (10(-1)) and is five times higher than the one measured in CO2 pulsed plasma (2 x 10(-2)). This latter result is attributed to competition effect at surface sites between CO and O. Finally, we point out the influence of water molecule wall adsorption on O-atom kinetics in H2O and O-2/HMDSO pulsed plasmas. During the post-discharge, H2O and/or OH molecules adsorbed at the reactor walls strongly reduce the O-atom loss coefficient. During the discharge, ion bombardment enhances desorption of molecules leading to an increase in the O-atom loss coefficient.
Added by: Laurent Cournède |