Study of structural, optical, and paramagnetic properties of Zn1-xCoxS nanoparticles prepared via co-precipitation

Co-doped ZnS (Zn1-xCoxS) nanoparticles were successfully synthesized by the chemical co-precipitation method. X-ray diffraction (XRD) patterns showed that nanoparticles were polycrystalline in nature with the cubic crystal structure. A reduction in the lattice parameter for Co-doped ZnS nanoparticles was observed, indicating that Co(2+)ions are incorporated into the ZnS matrix. The average crystallite size of prepared nanoparticles calculated using Scherrer's formula and found to be 2-3 nm. The crystallite size and microstrain of samples were investigated by the W-H analysis method. EDX spectra of doped samples confirmed the presence of the elements Zn, S, and Co. The field emission-scanning electron microscope (FE-SEM) images of nanoparticles are spherical with agglomeration. UV-visible measurements revealed that the optical bandgap of Zn1-xCoxS nanoparticles decreased with increasing cobalt concentration. Magnetic properties showed a paramagnetic-like behavior in all samples prepared at room temperature.