Influence of exposure time of LASER radiations on structural, optical, nonlinear optical and dielectric results of Sb_2Se_3 nanofilms

摘要

Sb_2Se_3 thin films which prepared using thermal evaporation were irradiated using LASER beam with different times of exposure (t_(expos)). X-ray diffraction (XRD) results showed that the structure of these samples had changed from amorphous structure to polycrystalline structure with (t_(expos))). The surface topography of these samples were studied using scanning electron microscopy (SEM). The measured optical parameters such as transmission (T) and reflection (R) were effected by these radiations. The determined optical energy gap (E_g) increases with (t_(expos)). The values of oscillating energy (E_o) and dispersion energy (E_d) increased with (t_(expos)). The dielectrical results such as dielectric loss (ε~) and dielectric tangent loss (ε~()) were affected and increase with (t_(expos)). The determined values for both real part of optical conductivity (σ_1) and imaginary part of optical conductivity (σ_2) increase also with (t_(expos)). The nonlinear optical parameters such as, nonlinear refractive index (h_2) and third-order nonlinear optical susceptibility (χ~((3))). The nonlinear results affected with (t_(expos)). Finally, the density of states and Fermi level position for these samples were determined optically.