Structural, optical and magnetic properties of (Cu, Ni) co-doped ZnS nanoparticles

Abstract

Un-doped and (Cu, Ni) co-doped ZnS nanoparticles have been successfully synthesized by chemical co-precipitation method using zinc acetate [Zn (CH3COO)2·2H2O], sodium sulfide (Na2S), Nickel Chloride [NiCl2·6H2O] and Copper acetate tetra hydrate [Cu (CH3COO)2·4H2O] as raw materials under the capping agent (PVP). The XRD results show that the prepared samples are in cubic blended structure. The average crystalline sizes of pure and (Cu, Ni) co-doped ZnS are found to be around 2–3 nm. The crystal structure of the ZnS does not change with the co-doping of Cu and Ni, but crystalline size increases by increasing Cu from 3 to 5 mol% at 3 mol% of Ni as constant. These results have been confirmed by transmission electron microscopy (TEM). The crystalline size of the samples from TEM is 3–5 nm, which is in good agreement with the XRD results. The Raman studies reveal that the obtained peaks at 270, 350, 260 and 470 cm− 1 are good agreement with standard Raman transverse optical mode (TO) and longitudinal optical mode (LO), and suggest that the pure and co-doped samples have cubic blended structure. SEM and TEM micro graphs of the (Cu, Ni) co-doped nanoparticles are spherical in shape with agglomeration. The EDAX spectra show the chemical composition of samples are in stoichometric proportion to ZnS. Optical absorption spectra show the absorption edge at 310 nm. Photoluminescence (PL) has been studied with excitation wavelength of 306 nm. The un-doped and (Cu, Ni) co-doped sample exhibit sharp emission peaks at 438, 450 and 466 nm with decreasing intensity. The magnetic measurements reveal that (Cu, Ni) co-doped nanoparticles exhibit room temperature ferromagnetism (RTFM).