Effect of Indium Doping Zinc Sulfide Nanostructures on the Physical and Sensing Properties via Chemical Spray Pyrolysis

Abstract

Indium-doped ZnS samples with doping levels of 0%, 1%, and 3% were fabricated using the chemical spray pyrolysis (CSP) method. XRD patterns confirmed the presence of a cubic zinc blend structure of both pure and Indium-doped ZnS samples. The crystallite size slightly increased with the concentration of indium, attributed to the substitution of indium within the ZnS lattice. AFM provided microscopic insights into the surface structure, allowing for the visualization and characterization of surface topographies. SEM images show transformation in ZnS films with Indium doping: flat islands to spherical nano-grains, indicating size reduction correlating with Indium concentration, influenced by ZnS-Indium interaction during synthesis. The optical parameters of nanostructures were investigated with doping and the incorporation of indium substitute for Zn ions. Indium doping in ZnS films increases resistance and alters gas sensing properties by affecting charge carrier mobility and adsorption efficiency. Higher Indium doping in ZnS films reduces sensitivity to NO2 gas due to changes in charge carrier mobility and film structure.