INDIUM INCORPORATION EFFECTS ON OPTICAL PROPERTIES OF QUATERNARY CHALCOGNIDE Se-Zn-Te-In FILMS

Amorphous semiconducting thin films of Se90-xZn5Te5Inx (x=0, 2, 4, 6, 8 and 10 at. %) are deposited on glass substrates by thermal evaporating technique with thickness about of 1000 nm. The transmittance spectra are investigated by Swanepoel method to compute the optical coefficients and parameters in the spectral region of (400–2500) nm, such as absorption coefficient α, extinction coefficient k, optical band gap, Eg and refractive index, n. The optical absorption edge is described by using the non-direct transition model in terms of Tauc relation. The obtained values of both n and k were found to be dependent of the In content in the investigated samples. Also, other parameters have been computed like the real, (εr) and imaginary (εi) parts of complex dielectric constants. The dispersion parameters (dispersion energy, Ed, oscillation energy Eo) were discussed according to the single oscillator Wemple–DiDomenico model. The non-linear refractive index, n2 was computed by using Tichy-Ticha and Fourier-Snitzer relationships.