Eur. Phys. J. Plus (2022) 137: 358
https://doi.org/10.1140/epjp/s13360-022-02564-3

Regular Article

On the structural and optical aspects of GeTeSeGa thermally evaporated chalcogenides thin films for infrared applications

¹ Department of Physics and Materials Science, Jaypee University of Information Technology, 173234, Waknaghat, Solan, India
² Applied Science Department, National Institute of Technical Teachers Training and Research, Sector 26, 160019, Chandigarh, India

^a ektasharmaphy@gmail.com

Received: 31 December 2021
Accepted: 6 March 2022
Published online: 18 March 2022

Abstract

The transparency of GeTeSeGa chalcogenide glasses in the NIR region makes them a promising candidate for low transmission loss application. The present study investigates the effect of substituting selenium by gallium on the optical parameters of Ge₁₀Te₈₀Se_10−xGa_x (x = 2, 6, 10) chalcogenides thin films in the near-infrared range (1000 nm–2600 nm). The thermal evaporation technique at room temperature has been used to prepare the films. Two fundamental optical constants, optical band gap and refractive index, have been obtained using the Tauc extrapolation approach and Swanepoel method. The absorption coefficient, refractive index, and extinction coefficient have been analysed using the single transmission spectra. The results indicate that as Ga content increased from 2 to 10 at%, the parameters such as absorption coefficient, extinction coefficient, the real and imaginary part of dielectric constant, and optical conductivity increased, while optical band gap ($E_g^{\mathit{opt}}$) and oscillator strength decreased. $E_g^{\mathit{opt}}$ decreases from 0.934 to 0.790 eV. The nonlinear parameters have also been analysed. The high nonlinear refractive index and third-order nonlinear susceptibility may make these materials applicable for high-speed communication fibres. These results indicate that the investigated samples may be suitable for several optoelectronic applications.