Room temperature investigations on optical and magnetic studies of Co_xZn_1−xS nanorods

In this report, structural optical and magnetic properties of Co_xZn_1−xS (x=0, 0.01, 0.05 and 0.1) nanorods have been investigated at room temperature. The average diameter and length of as synthesized nanorods, analyzed using transmission electron microscopy (TEM), are ∼10 nm and ∼100 nm, respectively. The crystal structure of Co_xZn_1−xS nanorods, studied using X-ray diffraction (XRD), indicates wurtzite structure with lattice parameters, a=3.84 Ǻ and c=6.25 Ǻ for Co_xZn_1−xS (x=0) nanorods which are found decreased with increased Co concentration in ZnS lattice. The band gap of Co-doped ZnS nanorods has been found to be blue shifted as compared to the undoped counterpart. Emission spectra indicate two peaks at 422 nm and 485 nm. Emission intensity increases in case of Co_xZn_1−xS (x=0.01, 0.05) nanorods, and quenches in Co_xZn_1−xS (x=0.1) nanorods. The ferromagnetization has been observed in case of Co-doped ZnS nanorods, whereas, undoped ZnS nanorods exhibit mixed diamagnetic-ferromagnetic behavior. The magnetization increases with increased Co concentration. - Highlights: • Cobalt doped wurtzite ZnS nanorods synthesized via solvothermal technique. • Absorption edge blue shifted with Co concentration. • PL intensity increased at lower Co concentration, but, decreased at higher concentration. • Strong ferromagnetic character indicated with increased Co content