Influence of top layer on the linear and nonlinear optical parameters of Ag(Te)/As50Se50 bilayer thin films

Sahoo, D and Priyadarshini, P and Alagarasan, D and Ganesan, R and Varadharajaperumal, S and Naik, R (2021) Influence of top layer on the linear and nonlinear optical parameters of Ag(Te)/As50Se50 bilayer thin films. In: Indian Journal of Physics .

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Abstract

The present paper illustrates the influence of the top Ag and Te thin layer on the linear and nonlinear optical properties of Ag(Te)/As50Se50 bilayer thin films. The As50Se50 and Ag(Te)/As50Se50 bilayer thin films were prepared by thermal evaporation technique under high vacuum conditions. The X-ray diffraction study showed no structural changes, whereas the UV�Visible spectroscopy data showed the changes in optical properties due to top layer deposition. From the recorded optical transmission data, the optical parameters, such as absorption coefficient, extinction coefficient, optical bandgap, Tauc parameter, Urbach energy, linear refractive Index, oscillator energy, dispersion energy, high-frequency dielectric constant and carrier concentration, were evaluated. The transmittance decreased and the absorption coefficient increased along with the increase in extinction coefficient. The optical bandgap decreased due to the increase in defect states and the degree of disorder. The dispersion of the refractive index was analyzed by the single oscillator Wemple�Di Domenico model. The third-order nonlinear susceptibility (�(3)) and nonlinear refractive index (n2) were calculated from the linear optical parameters using semi-empirical relations. The linear, nonlinear refractive index and (�(3) change was found to be more in Te/As50Se50 film than that of Ag/As50Se50 film as compared with the host As50Se50 film. The surface morphology was investigated by field emission scanning electron microscopy. The tuning of optical properties by simple layer deposition on the host matrix can be used in various optoelectronic applications. © 2021, Indian Association for the Cultivation of Science.

Item Type:	Journal Article
Publication:	Indian Journal of Physics
Publisher:	Springer
Additional Information:	The copyright for this article belongs to Springer
Keywords:	Bandgap; Nonlinear properties; Optical properties; Refractive index; Thin films Bandgap; Nonlinear properties; Optical properties; Refractive index; Thin films
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering Division of Physical & Mathematical Sciences > Physics
Date Deposited:	31 Dec 2021 06:01
Last Modified:	31 Dec 2021 06:01
URI:	http://eprints.iisc.ac.in/id/eprint/67692

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