Synthesis and characterization of the chemically deposited SnS_1−x Se_x thin films: structural, linear and nonlinear optical properties

Abstract

This article reported the synthesis of tin sulfide selenide (SnS_1−x Se_x) thin films with different compositions (0 ≤ x ≤ 1) using a cost-effective chemical bath deposition technique. The structural properties of the chemically synthesized SnS_1−x Se_x thin films were analyzed by means of the X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The XRD results demonstrate that all the chemically synthesized SnS_1−x Se_x thin films are polycrystalline and displayed an orthorhombic phase corresponding to the different compositions. The compositional elements of the SnS_1−x Se_x thin films were investigated via an energy dispersive X-ray analysis (EDAX). The optical study on the SnS_1−x Se_x thin films displayed that the chemically deposited SnS_1−x Se_x films exhibited a direct allowed optical transition and by increasing the Se content the magnitudes of the direct bandgap were decreased from 1.41–1.23 eV while the Urbach energy was increased. The effect of composition on the skin depth δ, absorption coefficient α, linear refractive index n and the static refractive index n_o of the SnS_1−x Se_x thin films was studied. Additionally, the results displayed that there is an improvement in the magnitudes of the nonlinear refractive index n₂, optical conductivity, third-order nonlinear optical susceptibility $\chi^{\left( 3 \right)}$ and the electrical conductivity of the SnS_1−x Se_x thin films occurred by increasing the selenium content.