Interpretation of the change in optical constants of different compositions of Ge-Se-In in terms of cohesive energy

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• 作者：E.R. Shaaban ; ^{esam_ramadan2008@yahoo.com}
• 关键词：A. Chalcogenides ; A. Thin films ; B. Vapour deposition ; C. X-ray diffraction ; D. Optical properties
• 刊名：Journal of Physics and Chemistry of Solids
• 出版年：2012
• 期刊代码：69_00223697
• 类别：ch
• 出版时间：September, 2012
• 卷：73
• 期：9
• 页码：1131-1135
• 文件大小：798 K

摘要

Compositional dependencies of the optical and physical properties of as-deposited amorphous Ge_xSe_90鈭?em>xIn₅ films (with 5鈮?em>x鈮?0 at%), prepared by thermal evaporation have been studied. The optical energy gap is derived from Tauc's extrapolation in the strong absorption region in terms of transmission and reflection spectra. The relationship between the optical gap and chemical composition of the Ge_xSe_90鈭?em>xIn₅ (with 5鈮?em>x鈮?0 at%) amorphous system is discussed in terms of the chemical bond approach. The refractive index, n and film thickness, d have been determined by an envelope method using transmission spectra. It is observed that the refractive index, n of Ge_xSe_90鈭?em>xIn₅ thin films increases with increasing x, over the entire spectral range, which is related to both the increased density and average coordination number.