Effect of Mn co-doping on the structural, optical and magnetic properties of ZnS:Cr nanoparticles

ZnS and Zn0.97Mn0.03S, Zn0.97Cr0.03S and Zn0.94Mn0.03Cr0.03S nanoparticles were synthesized by chemical co-precipitation method using ethylene diamine tetra acetic acid (EDTA) as stabilizer. energy-dispersive spectroscopy (EDS) confirmed the presence of Mn and Cr in the samples in near stoichiometric ratio. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) studies showed that Mn and Cr dopants entered the ZnS cubic lattice as substituents. The band-gap was found to be in the range of 3.81-4.09 eV from diffusion reflectance spectral (DRS) studies. In PhotoLuminescence (PL) spectra a sulfur-vacancy related PL band around 430 nm, a PL band associated with the T-4(1) -> (6)A(1) transition of Mn2+ and PL peaks associated with Cr were observed. Electron paramagnetic resonance (EPR) spectra exhibited resonance signals characteristic of Mn2+ and Cr3+. Vibrating sample magnetometer (VSM) studies revealed that ZnS: Cr nanoparticles exhibited room temperature ferromagnetism and in ZnS: Cr nanoparticles co-doped with Mn a suppression of room temperature ferromagnetism was noticed. (C) 2012 Elsevier B.V. All rights reserved.