Experimental and modeling study of ZnO:Ni nanoparticles for near-infrared light emitting diodes.

This work is devoted to the synthesis and study of the different properties of ZnO nanoparticles (NPs) doped with the Ni element. We have used a simple co-precipitation technique for the synthesis of our samples and various structural, morphological and optical techniques for their analysis. Energy-Dispersive X-ray spectroscopy (EDX) confirms the stoichiometry of the samples. The X-Ray Diffraction (XRD) patterns reveal the hexagonal wurtzite phase of polycrystalline ZnO with a P 63 mc space group. Debye Scherrer and Williamson-Hall methods show that the average size of crystallites is around 40 nm. Transmission electron microscopy (TEM) images confirm the XRD results. The optical spectrum of Zn 0.95 Ni 0.5 O shows the presence of near-band-edge (NBE) ultraviolet emission. The absorption defect bands appearing near the blue-green region and near infrared emission are attributed to the Ni 2+ intra-3d luminescence. The electronic structure of the Ni 2+ doped ZnO NPs confirms the T d site symmetry of Ni 2+ in the ZnO host crystal and leads to a perfect correlation between calculated and experimental energy levels.