Optical properties of quaternary a-Ge15-x Sbx Se50 Te35 thermally evaporated thin-films: refractive index dispersion and single oscillator parameters

The present research is allocated to study the essential optical properties and parameters, of thin-film samples of quaternary Ge15-xSbxSe50Te35 glassy matrices (0 <= x <= 15 at. wt. %) such as: the single effective oscillator-dispersion parameters, dielectric characteristics and some non-linear optical constants. The current study is a continuation of a previous work, which has been published before. Bulk glasses are synthesized using conventional melt quench, while thin films are deposited via thermal evaporation method. X-ray diffraction patterns expose the amorphous nature of all prepared bulk and film samples. Energy dispersive of X-ray analysis also reveals a good match between the calculated and the measured compositional element percentages of all the samples. The optical and dielectric properties of film samples are studied depending upon transmittance, T and reflectance, R spectrophotometric measurements. Optical refractive index (n) and extinction coefficient (k) are used to estimate many crucial dielectric and opto-electrical parameters. An increase in the values of the normal refractive index, static refractive index, single oscillator energy, lattice-dielectric constant, high-frequency dielectric constant, charge carrier concentration, volume energy loss functions, third order susceptibility is found. On the contrary, dispersion energy, oscillator strength, surface energy loss function, plasma frequency and electronegativity values are found to decrease as the Sb-percentage in the Ge-Sb-Se-the network increases. The interrelationships among investigated parameters have been extensively studied and discussed. The present film samples can be employed in the nonlinear optical applications and devices.