Composition and temperature dependence of the low-frequency Raman scattering in Ge-As-S glasses

Boulmetis, YC; Perakis, A; Raptis, C; Arsova, D; Vateva, E; Nesheva, D; Skordeva, E

dc.contributor.author	Boulmetis, YC	en
dc.contributor.author	Perakis, A	en
dc.contributor.author	Raptis, C	en
dc.contributor.author	Arsova, D	en
dc.contributor.author	Vateva, E	en
dc.contributor.author	Nesheva, D	en
dc.contributor.author	Skordeva, E	en
dc.date.accessioned	2014-03-01T01:20:01Z
dc.date.available	2014-03-01T01:20:01Z
dc.date.issued	2004	en
dc.identifier.issn	0022-3093	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/15814
dc.subject	Free Volume	en
dc.subject	High Frequency	en
dc.subject	Raman Scattering	en
dc.subject	Raman Spectra	en
dc.subject	Temperature Dependence	en
dc.subject	Low Frequency	en
dc.subject.classification	Materials Science, Ceramics	en
dc.subject.classification	Materials Science, Multidisciplinary	en
dc.subject.other	Composition	en
dc.subject.other	Defects	en
dc.subject.other	Germanium compounds	en
dc.subject.other	Mathematical models	en
dc.subject.other	Phonons	en
dc.subject.other	Raman scattering	en
dc.subject.other	Specific heat of solids	en
dc.subject.other	Stoichiometry	en
dc.subject.other	Stress analysis	en
dc.subject.other	Ternary systems	en
dc.subject.other	Thermal effects	en
dc.subject.other	Binary chalcogenide glasses	en
dc.subject.other	Boson peak frequency	en
dc.subject.other	Glass composition	en
dc.subject.other	Temperature dependence	en
dc.subject.other	Glass	en
dc.title	Composition and temperature dependence of the low-frequency Raman scattering in Ge-As-S glasses	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.jnoncrysol.2004.06.032	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.jnoncrysol.2004.06.032	en
heal.language	English	en
heal.publicationDate	2004	en
heal.abstract	The Raman spectra of `stoichiometric' (GeS2)(X)(As2S3)(1-x) glasses are presented for various compositions (x = 0.40, 0.60, 0.80, 0.83, 0.90) and compared to that of the `non-stoichiometric' Ge0.30As0.10S0.60 glass (in which there is excess of Ge with regard to the stoichiometric system). The study is focused on the variation of the low-frequency Boson peak with glass composition and temperature. The ratio of intensity of the as-recorded Boson peak to that of the high frequency main molecular band remains almost composition-independent for all glasses, except for the non-stoichiometric one. This ratio is considerably larger in the latter glass, implying a higher degree of disorder which is attributed to an increased number of defects. In the (GeS2)(x)(As2S3)(1-x) glasses, there is evidence of a shift of the Boson peak towards the lower frequencies with increasing Ge-content, indicating an increase of the correlation length of the medium range structure. On the other hand, the non-stoichiometric glass displays a lower Boson peak frequency than any (GeS2)(x)(As2S3)(1-x) glass, implying, again, a higher correlation length of the medium range structure. Both these results, i.e., the shifts towards the lower frequencies, are interpreted in terms of the higher free volume displayed by the Ge-rich glasses. In the case of the stoichiometric (GeS2)(0.83)(As2S3)(0.7) (or Ge0.25As0.10S0.65) glass and the non-stoichiometric Ge0.30As0.10S0.60 one, Raman spectra have also been measured over the temperature range 20-295K and shown significantly different dependence. Comparison of the intensity variation of the BP with temperature further confirms the higher degree of disorder of the non-stoichiometric glass. Finally, the reduced BP intensities of the glasses show almost the same spectral profiles over the entire temperature range, thus displaying universal lineshape behavior with temperature. (C) 2004 Elsevier B.V. All rights reserved.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	Journal of Non-Crystalline Solids	en
dc.identifier.doi	10.1016/j.jnoncrysol.2004.06.032	en
dc.identifier.isi	ISI:000225555600026	en
dc.identifier.volume	347	en
dc.identifier.issue	1-3	en
dc.identifier.spage	187	en
dc.identifier.epage	196	en