Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5360188 | Applied Surface Science | 2009 | 5 Pages |
Abstract
Se90Te10âxAgx (0 â¤Â x â¤Â 6) compositions were prepared by quenching technique. Thin films with different thicknesses of the obtained compositions were deposited on dry clean glass substrates by thermal evaporation technique. Energy dispersive X-ray spectroscopy (EDX) indicates that samples are nearly stoichiometric. X-ray diffraction patterns indicate that they are in the amorphous state. The optical constants, the refractive index n and the absorption index k, have been calculated from transmittance T and reflectance R through the spectral range of 400-2500 nm for the studied films with different thicknesses (165-711 nm). From the analysis of refractive index n data, high frequency dielectric constant Éâ was determined. Both Éâ and n are found to decrease with the increase of Ag content. The optical band gap Egopt is calculated for all compositions from the absorption coefficient analysis. The effect of the Ag addition on the obtained optical parameters has been discussed. The analysis of absorption index k data, revealed the existence of allowed indirect transitions for all compositions. It is indicated also that Egopt increase with increasing Ag content.
Keywords
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Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
A.E. Bekheet, N.A. Hegab, M.A. Afifi, H.E. Atyia, E.R. Sharaf,