Exploration of the impact of indium-doping on the microstructural, dispersion, linear, and nonlinear optical properties of the ZnS thin films

Abstract

Good quality pure and indium-doped ZnS layers (containing 4, 9, and 12 wt% In) were produced using an economical nebulizer spray pyrolysis technique. The XRD observations indicate a cubic structure for the examined indium-doped ZnS layers. The crystallite size decreased from 54.58 to 23.68 nm with the augmentation of indium content from 4 to 12 wt%. The optical band gap of the studied layers decreased from 3.53 to 2.94 eV as the indium was introduced into ZnS, although the Urbach energy values enhanced from 0.78 to 0.86 eV with the rise in indium doping from 4 to 12 wt%. Furthermore, the refractive index of the examined layers increased from 2.63 to 3.81 with the augmentation of indium content from 4 to 12 wt%. Investigating nonlinear optical properties involves augmenting the nonlinear refractive index of indium-doped ZnS layers by increasing the indium concentration from 4 to 12 wt%. The study of the optoelectrical parameters reveals enhancements in optical conductivity, optical carrier concentration, electrical conductivity, optical dielectric constants, and relaxation time through an increased indium ratio. The indium-doped ZnS exhibited n-type conductivity.