Compositional variation of short- and intermediate-range structure and chemical order in Ge-As sulfide glasses: A neutron diffraction study
Journal of Physical Chemistry C, cilt.112, sa.18, ss.7263-7269, 2008 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 112 Sayı: 18
- Basım Tarihi: 2008
- Doi Numarası: 10.1021/jp7115388
- Dergi Adı: Journal of Physical Chemistry C
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Sayfa Sayıları: ss.7263-7269
- Boğaziçi Üniversitesi Adresli: Hayır
Özet
The structures of chalcogenide glasses in the Ge-As-S system with Ge:As =1:1 and with S concentration varying between 33.3 and 70.0 atom% have been studied using neutron diffraction. Ge and As atoms are primarily heteropolar bonded to S atoms in stoichiometric and S-excess glasses. Formation of homopolar As - As bonds at low and intermediate levels of S-deficiency results in violation of chemical order and in the formation of As-rich structural moieties. Ge takes part in metal-metal bonding, predominantly via the formation of Ge - As bonds, only in the highly S-deficient glasses once all the As atoms are used up in homopolar bonding. Incorporation of tetrahedrally coordinated Ge into the structure disrupts the topological continuity of the low-dimensional As-rich clusters and the GeS2 network. These intermediate-range order structural orderings are manifested in the compositional dependence of the intensity, position, and width of the first sharp diffraction peak in the structure factor. © 2008 American Chemical Society.