Structural, optical and electronic characteristics of Cu and Mg-doped nano MnS sample prepared by molten salt solid state reaction

Abstract

Nano Mn0.95M0.05S (M ≡ Cu, Mg) samples were produced using molten salt solid state reaction method. Rietveld analysis of X-ray diffraction data was applied to investigate the percentage of phases developed and their structural parameters in the obtained samples. Analysis evidenced the incorporation of Cu and Mg into the MnS lattice. Diffraction patterns of pristine and Mg-doped samples exhibited biphasic MnS structure of hexagonal γ-MnS (wurtzite) and cubic β-MnS (zincblende) phases, while the Cu-doped sample exhibited only cubic phase for MnS; both doped samples contained a minor Mn3O4 phase. The selected area electron diffraction confirmed the formed phases in the prepared samples. The characteristic vibrational bands in each sample were investigated using Fourier transform infrared technique. The direct optical band gap of MnS, Cu or Mg-doped MnS are (3.04, 3.17), (3.52, 3.88) and (3.5, 3.91) eV respectively. The effect of doping on full width at half maximum, intensity and emitted colors of the photoluminescence spectra was studied. The effect of doping on the absorbance, refractive index, extinction coefficient, static dielectric constant and electric properties of MnS (hexagonal wurtzite structure) was explored using the density functional calculation. The emitted colors from doped nano MnS especially with Cu could be effectively used in LEDs applications.