Optical properties and new vibrational modes in carbon films

Gioti, M; Papadimitriou, D; Logothetidis, S

dc.contributor.author	Gioti, M	en
dc.contributor.author	Papadimitriou, D	en
dc.contributor.author	Logothetidis, S	en
dc.date.accessioned	2014-03-01T01:15:45Z
dc.date.available	2014-03-01T01:15:45Z
dc.date.issued	2000	en
dc.identifier.issn	0925-9635	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/13717
dc.subject	amorphous carbon films	en
dc.subject	ellipsometry	en
dc.subject	Raman spectroscopy	en
dc.subject	sputtering	en
dc.subject.classification	Materials Science, Multidisciplinary	en
dc.subject.other	TETRAHEDRAL AMORPHOUS-CARBON	en
dc.subject.other	RAMAN-SPECTROSCOPY	en
dc.subject.other	DIAMOND FILMS	en
dc.subject.other	SCATTERING	en
dc.subject.other	DEPENDENCE	en
dc.subject.other	GRAPHITE	en
dc.title	Optical properties and new vibrational modes in carbon films	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S0925-9635(00)00244-2	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0925-9635(00)00244-2	en
heal.language	English	en
heal.publicationDate	2000	en
heal.abstract	The optical properties and vibrational modes of amorphous carbon (a-C) films were studied by spectroscopic ellipsometry (SE) and Raman spectroscopy. The films were prepared by sputtering, at various energies E-i (low to high), of the argon species bombarding the film surface during deposition. The SE spectra were analysed by the Tauc-Lorentz model to describe the dielectric function is an element of(omega) of the bulk films and to determine their optical gaps. The calculated is an element of(omega) revealed fundamental differences in the electronic structure and C-C bonding of the a-C films and can be described, in general, with two oscillators: one at similar to 4 eV, attributed to the pi-->pi(*) (sp(2) bonds), and one in the range 10-15.5 eV, attributed to the average of sigma-->sigma' (sp(3) bonds) and high-energy (sp2 bonds) absorption. A strong optical absorption at similar to 1.2 eV appears only in films developed with high E-i (greater than or equal to 130 eV). The Raman spectra of the a-C films show the following behavior with increasing E-i: (1) the strengths of disordered 'D' and graphite'G' peaks are gradually reduced and finally disappear; (2) three peaks (at similar to 1250, 1295 and 1330 cm(-1)) appear, reinforced at high E-i; and (3) at high E-i two well-defined peaks at similar to 1556 and 2330 cm(-1) are also detected. All of the above indicate the formation of a more ordered amorphous network with increasing Ei, and a new crystalline structure is formed at high E-i. (C) 2000 Elsevier Science S.A. All rights reserved.	en
heal.publisher	ELSEVIER SCIENCE SA	en
heal.journalName	DIAMOND AND RELATED MATERIALS	en
dc.identifier.doi	10.1016/S0925-9635(00)00244-2	en
dc.identifier.isi	ISI:000087382400103	en
dc.identifier.volume	9	en
dc.identifier.issue	3-6	en
dc.identifier.spage	741	en
dc.identifier.epage	745	en