LO-TO splittings in plasma-deposited siloxane films

dc.creatorTrasferetti, BC
dc.creatorDavanzo, CU
dc.creatorde Moraes, MAB
dc.date2003
dc.dateOCT 2
dc.date2014-11-16T19:17:25Z
dc.date2015-11-26T16:24:56Z
dc.date2014-11-16T19:17:25Z
dc.date2015-11-26T16:24:56Z
dc.date.accessioned2018-03-28T23:05:45Z
dc.date.available2018-03-28T23:05:45Z
dc.identifierJournal Of Physical Chemistry B. Amer Chemical Soc, v. 107, n. 39, n. 10699, n. 10708, 2003.
dc.identifier1520-6106
dc.identifierWOS:000185609600005
dc.identifier10.1021/jp027694d
dc.identifierhttp://www.repositorio.unicamp.br/jspui/handle/REPOSIP/52705
dc.identifierhttp://www.repositorio.unicamp.br/handle/REPOSIP/52705
dc.identifierhttp://repositorio.unicamp.br/jspui/handle/REPOSIP/52705
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1268519
dc.descriptionThe present work presents LO and TO functions in the mid-infrared region for thin films deposited from glow discharge plasmas of tetramethylsilane (TMS) diluted either in Ar or O-2 or in mixtures of these two gases. These functions were calculated through the Kramers-Kronig analysis of transmittance spectra of the films supported on KBr disks. To correlate structural aspects of the films with the observed LO-TO splittings, a group frequency analysis based on the literature was made. Such an analysis indicated that the films deposited from the TMS Ar mixture were formed mainly by a polycarbosilane skeleton, whereas those deposited from TMS-O-2 and TMS-O-2-Ar were formed by a random network of four types of distorted tetrahedra: (CH3)(3)SiO0.5, (CH3)(2)SiO, (CH3SiO1.5), and SiO2. From the LO-TO splitting for the asymmetrical stretching mode of Si-O-Si groups, the density and the presence of defects in samples obtained from TMS-O-2 and TMS-O-2-Ar mixtures were evaluated. The number of defects increased as the Ar-to-O-2 flow rate decreased. We also report for the first time LO-TO splittings for bands related to the bending of CH3 and to the stretching of the Si-C bond in Si(CH3)(x) groups. The knowledge of such splittings is very important for a correct evaluation of the infrared reflection -absorption spectra taken at oblique incidence of thin films containing Si-O bonds and Si(CH3)(x) groups deposited on metals.
dc.description107
dc.description39
dc.description10699
dc.description10708
dc.languageen
dc.publisherAmer Chemical Soc
dc.publisherWashington
dc.publisherEUA
dc.relationJournal Of Physical Chemistry B
dc.relationJ. Phys. Chem. B
dc.rightsfechado
dc.sourceWeb of Science
dc.subjectInfrared-reflectance Spectra
dc.subjectChemical-vapor-deposition
dc.subjectGel-derived Silica
dc.subjectThin-films
dc.subjectVibrational-spectra
dc.subjectSi/sio2 Interface
dc.subjectAb-initio
dc.subjectSpectroscopy
dc.subjectOxygen
dc.subjectAbsorption
dc.titleLO-TO splittings in plasma-deposited siloxane films
dc.typeArtículos de revistas


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