Study of As - Se - Te glasses by neutron-, X-ray diffraction and optical spectroscopic methods

M. Fábián, E. Sváb, V. Pamukchieva, A. Szekeres, P. Petrik, S. Vogel, U. Ruett

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Abstract

The atomic structures of amorphous As 40Se (60-x)Te x (x = 10 and 15) and As 40Se 60 glasses have been investigated by neutron and high energy X-ray diffraction methods. The two datasets were modeled simultaneously by reverse Monte Carlo (RMC) simulation technique. The RMC simulations revealed a glassy network built-up from As(Se, Te) 3 pyramids in which Te atoms substitute Se atoms. The As - Se correlation function shows a strong and sharp first peak at 2.4 Å and two broad and much less intense peaks at 3.7 and 5.6 Å, related to 1st, 2nd and 3rd neighbor distances of the As - Se bonds, respectively. They are an evidence for existence of short and medium ordering in the studied glasses. The similarity of Θ Te - As - Te and Θ Se - As - Se bond distributions suggests that Te atoms have a similar role in the structure formation as Se atoms. The FTIR spectra analysis revealed impurity bonds of Se - H, As - O, Se - O, and Te - O in the glasses which contributed to enhanced absorption in visible spectral range. From the ellipsometric data analysis the optical constants and the energetic parameters of the studied glasses were established. The compositional variation of these parameters is explained in terms of chemical bonds formation and change in the density of charged defects.

Original languageEnglish
Pages (from-to)860-868
Number of pages9
JournalJournal of Non-Crystalline Solids
Volume358
Issue number4
DOIs
Publication statusPublished - Feb 15 2012

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Keywords

  • Disordered solids
  • Neutron diffraction
  • Optical properties
  • RMC simulation
  • X-ray diffraction

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Materials Chemistry

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