The effect of substitution of Sb with Zn on the optical and physical properties of Se90Sb10-xZnx (x = 0, 2, 4, 6, 10 at. %) thin films

Abstract

In the present study, the effect of substitution of Sb with Zn on the optical properties of Se90Sb10-xZnx (x = 0, 2, 4, 6, 10 at. %) thin films is discussed. Bulk samples are prepared using a conventional melt-quench technique. Amorphous thin films of the compositions are synthesized using thermal evaporation technique. Normal incidence transmission spectra of films is obtained in the spectral range of 400–1100 nm. The envelope method is applied to calculate the refractive index, followed by Cauchy's extrapolation. Spectral distributions of extinction coefficient, absorption coefficient and dielectric loss factor are obtained. Wemple-Didomenico single oscillator model is employed to study refractive index dispersion. The absorption coefficient is of the order of 104 cm−1, and the band-gap is calculated using Tauc’s extrapolation for the indirect transition. The increase in band gap with Zn addition is explained on the basis of chemical bond approach. Topological studies show that the system is in a rigid region The glass transition temperature, mean bond energy and density of the system is also increasing with the increase in Zn content. An effort is made to discuss all the parameters in terms of change in bond length, bond energy and connectedness of the glassy network.