INFLUENCE OF LOW CONCENTRATION OF Co IONS ON THE OPTICAL AND STRUCTURAL PROPERTIES OF ZnS NANOPARTICLES

Abstract

Zinc sulfide (ZnS) nanoparticles doped with cobalt ions (Co²⁺) have been prepared by the chemical bath deposition method (CBD) from homogeneous solutions of zinc acetate, cobalt acetate, thiourea and tri-sodium citrate as a complexion agent. The optical, and structural characteristics of Zn(_1-x) Co_x S (0.0≤ x ≤0.2) films have been investigated using photoluminescence (PL), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The PL spectrum of the thin films nanoparticles showed two emission peaks, the first at λ = 335 nm, refer to band to band transition and the second is at around λ = 660 nm. The intensity of the PL peaks in the red region increases with the increase of Co²⁺ concentration, the maximum intensity recorded was for x = 0.2 of Co²⁺doped. X-ray diffraction showed that the average size of ZnS doped Co is about 1.5 - 2.5nm, and three diffraction peaks corresponds to the cubic crystalline ZnS. The SEM micrographs showed variation in diffracted morphology with Co²⁺concentration, and the surface of the films became smoother with the rise of the Co²⁺ doping, the thickness of the films was estimated to be in the range of 223.3 - 461.2 nm.