Structural and optical properties of Ca²⁺ doped ZnS nanoparticles

In this work, we synthesized undoped ZnS and Ca²⁺ doped ZnS nanoparticles by chemical precipitation method. The structural and optical properties of the prepared nanoparticles have been analyzed using X-ray diffraction, Field emission scanning electron microscope, UV-vis-NIR spectrophotometer and Fluorescence spectroscopy. XRD patterns showed that the ZnS and ZnS:Ca nanoparticles have zinc blende structure with the crystallite sizes of about 7-8 nm range. The value of optical band gap has been found to be in the range 4.41-4.06 eV. Room temperature photoluminescence (PL) spectrum of the undoped sample exhibits emission in the blue region with multiple peaks under UV excitation. Ca²⁺ doped ZnS samples shows enhanced visible light emissions under the same UV excitation wavelength of 310 nm.