Unraveling the nonlinear optical behaviors of indium selenide thin films prepared by spin coating method

Abstract

We report the nonlinear optical properties of solution-processed indium selenide thin films. The films were synthesized by spin coating method at various annealing temperatures using thiol-amine cosolvents. During annealing, a facile mechanical stress on the thin films resulted in a transformation from β -In3Se2 to γ -In2Se3 phase. The X-ray diffraction (XRD) study confirmed the polycrystalline nature of both phases. The Scanning Electron Microscope (SEM) study revealed the uniform and smooth surface morphologies of the films. The linear optical properties including extinction coefficient, refractive index, dielectric function, and dispersion parameters for both β -In3Se2 and γ -In2Se3 phases were investigated. The dispersion parameters were calculated using the Wemple-DiDomenico model. Third-order nonlinear susceptibility and nonlinear refractive index of both phases were calculated to find their potential in nonlinear optical applications.