Influence of Synthesis Temperature on the Phases Developed and Optical Properties of Manganese Sulfide and Zinc Sulfide

Nano MnS and ZnS samples are prepared through a simple thermolysis procedure. The effect of synthesis temperature on the different phases formed and their percentages, and on the lattice parameters and crystallite size of MnS and ZnS is examined using Rietveld analysis for X-ray diffraction patterns. The minimum synthesis temperature at which MnS can be formed by the present simple procedure is 250 degrees C, while ZnS can be prepared at a lower temperature of 200 degrees C. For manganese sulfide, traces of Mn3O4 phase appear at 300 degrees C and increase with temperature, while ZnS resists oxidation until 500 degrees C; pure ZnO forms at 700 degrees C. The MnS and ZnS samples, obtained at all temperatures, are found to be biphasic; cubic and hexagonal. The nano nature of the samples and the particle morphology are investigated by high-resolution transmission electron microscopy. Fourier-transform infrared spectroscopy is applied to follow the characteristic vibration bands in both systems. The values of the different energy gaps depend on the crystallite size, phases' percentages, and the preparation temperature. The photoluminescence intensity and the emitted colors from MnS and ZnS depend on the synthesis temperature.