Synthesis and characterization of nanocrystalline zinc sulphide by wet chemical route

Nanometer-sized ZnS crystallites were synthesized by a wet chemical synthesis process. Thin films of these nanocrystallites were also prepared on glass substrates and annealed in vacuum at various temperatures. The nanocrystalline powders were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies. The thin films were characterized by UV-visible optical absorption spectroscopy. XRD and TEM data confirmed the nano sizes of the crystallites. Also they showed the typical interplanar spacings (d value) corresponding to the cubic phase of ZnS. Band gap value increased in the nanomaterial than the bulk value. Sizes of the nanocrystallites were also determined from the band gap shift. Annealing of the thin films modified the band structure and particle sizes were increased.