Structure and dynamics of Ge-As-S chalcogenide glasses monitored by low-frequency Raman scattering

Boulmetis, YC; Raptis, C; Arsova, D

dc.contributor.author	Boulmetis, YC	en
dc.contributor.author	Raptis, C	en
dc.contributor.author	Arsova, D	en
dc.date.accessioned	2014-03-01T02:43:34Z
dc.date.available	2014-03-01T02:43:34Z
dc.date.issued	2005	en
dc.identifier.issn	1454-4164	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/31475
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-22644432700&partnerID=40&md5=fb916f5ef602a397da212229a80e7dbe	en
dc.subject	Boson peak	en
dc.subject	Chalcogenide glasses	en
dc.subject	Glassy network dynamics	en
dc.subject	Phase transitions	en
dc.subject	Raman spectroscopy	en
dc.subject	Temperature dependence	en
dc.subject.classification	Materials Science, Multidisciplinary	en
dc.subject.classification	Optics	en
dc.subject.classification	Physics, Applied	en
dc.subject.other	NON-CRYSTALLINE SOLIDS	en
dc.subject.other	MEDIUM-RANGE ORDER	en
dc.subject.other	BOSON PEAK	en
dc.subject.other	AMORPHOUS SOLIDS	en
dc.subject.other	TEMPERATURE	en
dc.subject.other	TRANSITION	en
dc.subject.other	FORMERS	en
dc.subject.other	SPECTROSCOPY	en
dc.subject.other	TOPOLOGY	en
dc.subject.other	ALLOYS	en
dc.title	Structure and dynamics of Ge-As-S chalcogenide glasses monitored by low-frequency Raman scattering	en
heal.type	conferenceItem	en
heal.language	English	en
heal.publicationDate	2005	en
heal.abstract	The Raman scattering spectra of several "stoichiometric" (GeS2)(x)(As2S3)(1-x) glasses have been measured over temperatures ranging from 20 K, through the respective glass transition temperature T-g and up to a temperature close to melting point. For comparisons, similar temperature-dependent Raman spectra have been obtained for the "non-stoichiometric" Ge0.30As0.10S0.60 glass which is rich in Ge in relation to the above stoichiometry. All glasses studied belong to the stress-rigid network regime (mean coordination number r >= 2.475). Emphasis is given on the study of the low-frequency Boson peak (BP) and, in particular, its variation with composition and temperature which is related to the dynamics of the glassy network. The relative intensity of the BP to the high-frequency main molecular band is practically composition-independent in the stoichiometric glasses, but in the non-stoichiometric one is much larger, thus reflecting the higher degree of disorder in the latter. The Boson peak frequency decreases with increasing Ge-content in the (GeS2)(x)(As2S3)(1-x) glasses, while that of the Ge0.30As0.10S0.60 glass is the lowest than any stoichiometric composition, implying a higher correlation length of the medium-range order for the latter glass. The temperature dependence of the BP up to the respective Tg is manifested by either a slight smooth softening with increasing temperature, or by an almost temperature-independent frequency over this range of temperatures (20 K - T-g). As T-g is approached, all glasses show discontinuous (abrupt) changes in their BP characteristics (intensity and frequency), signifying the transition to a less rigid network regime. Further increase of temperature results in a sharp drop of the BP intensity for most glasses, which implies a transition to a more ordered network. The results confirm the close correlation between the BP and the medium-range order in network glasses. Also, it has been shown that monitoring the spectral characteristics of the BP constitutes a reliable technique for detecting critical phenomena in rigid glassy networks around T-g.	en
heal.publisher	NATL INST OPTOELECTRONICS	en
heal.journalName	Journal of Optoelectronics and Advanced Materials	en
dc.identifier.isi	ISI:000229987500008	en
dc.identifier.volume	7	en
dc.identifier.issue	3	en
dc.identifier.spage	1209	en
dc.identifier.epage	1216	en