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 4T1 → 6A1 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.

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► ZnS:(Cr, Mn) nanoparticles were synthesized by chemical co-precipitation method.
► Synthesized ZnS:(Cr, Mn) nanoparticles were in cubic phase.
► In PL spectra blue and orange emissions were observed in ZnS:(Cr, Mn) nanoparticles.
► FTIR spectra excludes that intact EDTA simply coexists with the ZnS nanoparticles.
► Room temperature ferromagnetism was observed in Mn co-doped samples.