Effects of composition ratio of nano ZnS on structural and optical characteristics of Eu-doped maghemite$/$ZnS nanocomposite system

Abstract

Fe_1.96Eu_0.04O₃ (FUO)$/$ZnS nanocomposite system was prepared using sol gel and thermolysis procedures. Structural analysis and phase percentage determination of different phases in the composite system was performed using synchrotron and conventional X-ray diffraction and Fourier transform infrared techniques. TEM images indicated a homogeneous particle morphology of spherical shape and narrow particle size distribution, 15–20 nm for the FUO phase and 2–3.5 nm for ZnS phase. SAED pattern of FUO confirmed the formation of cubic phase with space group $P4_{3} 32$. X-ray photoelectron spectroscopy analysis revealed that Zn, Eu and Fe ions in the nanocomposite system exhibited 2 + , (2 + / 3 +) and 3 + oxidation states, respectively. The effect of ZnS ratio on the optical characteristics, optical conductivity, electrical and nonlinear optical parameters of the nanocomposite was explored using the diffuse reflectance measurements. The direct optical band gap was reduced from 2 eV for FUO sample to 1.96 eV as the amount of ZnS in the (1–x) FUO/xZnS system became 50%. In the visible range, the optical conductivity σ_opt for all samples attained maximum values and the refractive index acquired minimum values (< 2) and slightly changed by the ZnS content.