Nickel Sub-lattice Effects on the Optical Properties of ZnO Nanocrystals

Nano-crystalline undoped and Ni doped ZnO (Ni-ZnO) nano-particles with compositional formula NixZn1-xO (x=0, 1, 3 and 5 mol %) were synthesized using sol-gel method. As nickel incorporated in to the ZnO matrix results were analyzed using different techniques such as XRD, SEM, EDS, UV-VIS and FT-IR techniques. X-ray diffraction (XRD) result reveals the formation of hexagonal wurtzite structure of all samples, while extra peak appears at 42.5o due to Ni sub-lattice in doped samples informs about the presence of doped species. In addition, the surface morphology of undoped ZnO has also been studied and discussed using scanning electron microscopy (SEM). Moreover, the energy bandgap of undoped and doped ZnO has also been measured using UV-VIS spectrometer. It is observed that the doping of sub-lattice affects the structure as well as the energy bandgap. Hence, by Ni- doping in ZnO nano-particles, the energy bandgap of Ni-ZnO can be tuned for various optical applications. The lattice parameters and crystallite sizes have also been determined using XRD and it has been observed that they changes with the increase of Ni amount. The crystal vibrational study has also been performed using FT-IR spectroscopy which gives the presence of the host as well as doped sub-lattice.