Linear and nonlinear optical properties of amorphous Se–Te–Sn–Cd films.

This research work reports the rigorous studies of the various optical properties of Cadmium containing amorphous thin films (TFs) of multicomponent Se–Te–Sn system. The optical characteristics of prepared TFs are analyzed by using the experimental spectral data of reflection/transmission in the range 4000 Å to 25000 Å. Knowing the spectral variation of the dispersion parameters, we have determined the optical band gap E g o p t and Urbach tail E e. After the addition of Cd, The Urbach energy E e value decreases for the parent Se–Te–Sn sample. The values of the optical bandgap for the present samples are found in the range from 1.24 eV to 1.43 eV with a reversal in trend at x = 4. The indirect optical transition is found in the current study that is confirmed by the transition power factor m. The high dielectric constant (ε ∞), as well as single-oscillator dispersion parameters, are also determined. The dependence of real ε′ and imaginary ε′′ components of optical dielectric constant, relaxation time τ, dissipation factor tan δ , and the optical/electrical conductivities (σ opt and σ ele) on photon energy hν were also studied for multi-components SeTeSnCd (STSC) system. The nonlinear optical characteristics of TFs are examined in terms of their susceptibility and nonlinear refractive index. A discussion has been also discussed about the potential values of the CB- and VB- bands, along with their location. We have observed an excellent agreement between the values of Tauc's constant B determined by Tauc's relation that is obtained by empirical fitting. The present glasses have been found useful for optoelectronic applications after their comparison with different cadmium-containing binary and ternary systems reported by other researchers. [Display omitted] [ABSTRACT FROM AUTHOR]