Anisotropic optical properties of ZnS thin films with zigzag structure

Abstract

ZnS sculptured thin films produced by thermal evaporation method using the glancing angle deposition technique at different deposition angles (0, 30, 60, 70 and 80${^{\circ }}$) are reported. The structural and optical properties of the prepared samples are investigated systematically using X-ray diffraction (XRD) and UV–VIS spectroscopy techniques. The XRD studies show cubic structure for the prepared films and deposition angle dependence of lattice constants, intrinsic stress, tensile stress and dislocation density. The obtained transmittance spectra in the range 380–850 nm for both s- and p-polarized light at normal incidence angle are used to study the s- and p-refractive indices and in-plane birefringence of the ZnS films. The maximum birefringence is evaluated at incident flux angle $\alpha = 70{^{\circ }}$. Both the refractive index and packing density of the films decrease with increasing deposition angle, which confirm the structural inhomogeneity and porosity nature of the films.