Abstract
► The present work deals with the incorporation the optical properties of amorphous Se with SbSn. ► High accuracy determination of the film thickness and the complex index of refraction. ► The allowed non-direct electronic transitions are mainly responsible for the photon absorption in the investigated films. ► The changes in the refractive index were discussed in terms of the single-oscillator model (Wemple–DiDomenico relationship). ► The obtained results were discussed in terms of the chemical-bond approach.
Different compositions of Se
100−
x
(SbSn)
x
(0
≤
x
≤
14
at.%) glasses were prepared by the well-known melt quench technique. Thin films of these glasses were prepared by thermal evaporation onto ultrasonic cleaned glass substrate. Transmittance spectra of these films were measured in the wavelength range 400–2500
nm by using Jasco double beam spectrophotometer. A straight forward analysis proposed by Swanepoel, based on the maxima and minima of the transmittance spectra, allows to accurate determination of the film thickness and the complex index of refraction. Increasing SbSn content at the expense of Se atoms is found to affect the refractive index and the extinction coefficient of these films. The refractive indexes were discussed in terms of the single-oscillator Wemple–DiDomenico model. The compositional dependence of the optical band gap for the Se
100−
x
(SbSn)
x
(0
≤
x
≤
14
at.%) thin films is discussed in terms of the chemical-bond approach.