Development and study of the structural and optical properties of hexagonal ZnO nanocrystals

ZnO is a promising member of the semiconducting materials of II-VI group. ZnO nanocrystals have shown potential applications in various novel technologies. In the present investigation of ZnO nanocrystals, a novel chemical route using Zinc acetate as organic precursor is being reported. ZnO nanocrystals were characterized using X-ray diffraction, scanning electron microscopy UV-visible (UV–vis) spectroscopy, and photoluminescence measurements. The X-ray diffraction studies reveal the typical hexagonal structure of ZnO nanocrystals along the preferred orientation of (101) and (100) planes. The optical bandgap of ZnO nanocrystals was found to be 3.50 eV from the absorbance spectrum, which is higher than that of the bulk ZnO material. A blueshift of 21 nm is observed in the excitonic transitions, which clearly indicates the formation of ZnO nanocrystals. Photoluminescence spectroscopy of the ZnO nanocrystals showed a strong emission peak at 365 nm near the band edge along with a weak green-yellow emission peak spanning the range of 450 to 600 nm. The blueshifting was also observed in the photoluminescence spectrum, in accordance with the UV–vis spectroscopy in contrast to the bulk ZnO material.