Isoelectronic substitution in Si(SxSe1−x)2 glasses
| Autor: | R. K. Grasselli, J.H. Harris, M. Tenhover, H. Scher, M. A. Hazle |
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| Rok vydání: | 1985 |
| Předmět: |
Work (thermodynamics)
Chemistry Alloy Substitution (algebra) engineering.material Composition (combinatorics) Condensed Matter Physics Electronic Optical and Magnetic Materials Crystallography symbols.namesake Chalcogen Molecular vibration Materials Chemistry Ceramics and Composites Tetrahedron engineering symbols Raman spectroscopy |
| Zdroj: | Journal of Non-Crystalline Solids. 69:249-259 |
| ISSN: | 0022-3093 |
| DOI: | 10.1016/0022-3093(85)90027-4 |
| Popis: | The atomic structure of Si(S x Se 1− x ) 2 glasses has been investigated using Raman spectroscopy. Relatively sharp well-defined modes occur for all compositions ( x ) that permit a quantitative analysis of the Raman spectra. Polarized A 1 vibrational modes are observed in the bond stretching region that correspond to the symmetric vibrations of Si(S 4− N Se N ) ( N = 0, 1, 2, 3, 4) tetrahedral units. The intensities of these lines smoothly change as the relative amounts of S and Se are varied in the alloy glasses. The description of the atomic structure of the Si-alloy glasses that emerges from this work is the Random Chalcogen Site Model (RCSM). In this model, the glassy network consists of extended, edge-sharing tetrahedral chains in which the chalcogen sites are randomly occupied by S and Se. This description of the structure of the Si-based glasses accurately accounts for the intensities and positions of the observed Raman lines. A splitting is observed in the A 1 mode that corresponds to the vibrations of the N = 2 tetrahedral units. This is shown to be a consequence of the medium range order present in these glasses. The changes in the relative intensities of the two N = 2 A 1 modes as a function of composition suggest that a refinement of the RCSM is necessary. The present results provide strong evidence for the edge-sharing tetrahedral chain model of the structure of glassy SiS 2 and SiSe 2 and illustrate an example of isoelectronic substitution in glasses. |
| Databáze: | OpenAIRE |
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