Optical properties of amorphous Se90-XIn10SbX thin film alloys

Journal article

Authors/Editors

Muiva, Cosmas

Research Areas

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Publication Details

Author list: Muiva CM, Mwabora JM, Sathiaraj TS, King JG

Publisher: Elsevier

Place: LAUSANNE

Publication year: 2016

Journal: Journal of Alloys and Compounds (0925-8388)

Journal acronym: J ALLOY COMPD

Volume number: 689

Start page: 432

End page: 438

Number of pages: 7

ISSN: 0925-8388

eISSN: 1873-4669

Languages: English-Great Britain (EN-GB)

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Abstract

Ternary thin film alloys of Se90-XIn10SbX (x = 1, 4, 10, 15 and 20) were synthesised by flash evaporation of the pre-melt quenched bulk samples under a vacuum of 10(-5) Torr. Optical absorption analysis pointed to indirect allowed transitions as the mechanism of excitation across the energy gap. The optical band gap (E-g) was evaluated on the basis of Wemple-Didomenico single oscillator model and Tauc's extrapolation method in the spectral region where the absorption coefficient, alpha >= 10(4) cm(-1). The refractive index (n), complex dielectric constant (epsilon), band tailing parameter (B), plasma frequency (omega(p)), single oscillator parameters (E-o and E-d) and lattice dielectric constant (epsilon(L)) were deduced for each alloy. The compositional dependence of optical and dielectric parameters was explained on the basis of chemical bond approach. The observed shift in the trends of E-g, E-d, epsilon(L) and omega(p) values at the composition where Sb = 4 at% was correlated to the usual chemical threshold at this composition. (C) 2016 Elsevier B.V. All rights reserved.

Keywords

Amorphous materials, Dielectric properties, Optical properties, thin films, Vapour deposition

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