Optical studies of undoped and doped ZnS (with Ni & Al) nano-particles

Extensive studies are done on semiconductor nano-particles because of their potential applications in opto-electronic devices. Semiconductor nano crystallites electronic devices have potential applications with the growth of science and technology. Optical properties of undoped and doped ZnS (with Ni and Al) are studied. ZnS and its doped nano crystals are grown into polyvinyl alcohol matrix synthesized by chemical route. Nanostructure is characterized with the help of X-ray diffraction (XRD) and Transmission Electron microscope (TEM). Surface morphology is studied with the help of Scanning Electron Microscope. Average particle size of ZnS, ZnS-Ni and ZnS-Al are found to be 7.5nm, 10nm and 11nm. Optical absorption studies were carried out with UV-VIS Spectrophotometer and showed a strong absorbance at wavelength 297.2 nm with a tendency towards blue shift. Peak of photoluminescence(PL) Emission spectra is found around 510 nm at room temperature for undoped ZnS. Ni dependent emission is found at 440nm and Al dependent emission is found around 510nm, which implies successful doping. X-ray Fluorescence studies show larger peak for Zn and S compared to dopant materials Ni and Al. PL studies also confirm presence of dopant in the nano-crystallites. SAED patterns show a set of three well-defined rings corresponding to diffraction from different planes of Nano crystallites of ZnS, ZnS-Ni and ZnS-Al.