Synthesis and Optical Property Studies of Undoped and Doped Zns (with Al & Ni) Nano-Particles


Rita Choudhury
Dr. Santanu Bardaloi


Undoped and doped Zinc Sulphide Nano particles with aluminium and nickel at different volume ratios using Polyvinyl alcohol matrix were synthesized by chemical route. These ZnS thin films posses a nanocrystalline structure, exhibit quantum size effects due to the small crystal size and produce a blue shift in the optical spectra. With the help of X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) Nanostructure is characterized. With the help of Scanning Electron Microscope (SEM) surface morphology is studied. We have prepared volume ratios of 5:2, 5:3 & 5:4 of ZnS, ZnS-Al and ZnS-Ni keeping pH = 1. In the volume ratio 5:2 absorption peak of undoped ZnS is found at 360 nm. After doping with Al the peak is found at 340 nm and doping with Ni it is found to be shifted to 290 nm. From PL studies excitation peaks of ZnS, ZnS-Al and ZnS-Ni are found at 540 nm, 510 nm and 460 nm. From UV and PL studies the effect of doping is well noticed and they support one another. But when volume ratios are changed to 5:3 and 5:4, no remarkable changes are noticed (from UV and PL studies). From TEM studies,   average particle sizes of ZnS, ZnS-Al and ZnS-Ni are found to be 10.5 nm, 9.9 nm and 10.01 nm, and from XRD studies it is found to be 6.9 nm. SAED patterns show a set of three well-defined rings corresponding to diffraction from different planes of Nano crystallites of ZnS, ZnS- Al and ZnS- Ni. .  X-ray Fluorescence studies show larger peak for Zn and S compared to dopant materials Al and Ni.