Sol-gel derived nanostructured zinc oxide for bright luminescence in ultraviolet and visible spectral regions

Nanostructured pure zinc oxide powder with granular and rod shaped morphologies has been synthesized employing a sol-gel process using zinc acetate as the precursor material and diethanolamine as the sol stabilizer. The effect of sintering temperature (750, 850, 950, 1050 and 1150 degrees C) on different properties of ZnO has been examined. The present work describes the structural, morphological and photoluminescence characteristics of zinc oxide. X-ray diffraction study has elucidated the formation of wurtzite hexagonal crystalline structure with the crystallite size varying in the nano-scale range between 20-30 nm. The scanning electron micrographs have shown the surface structure to be highly porous. The samples have demonstrated the presence of round clusters (200-500 nm) of uniformly distributed polycrystalline grains. The excellent luminescence in these samples in the UV and visible regions (green emission) is attributed to their nanocrystalline characteristics. The best photoluminescence response is found in the 950 degrees C sintered sample due to the presence of optimum size nanoparticles (dia.: 40 nm) and nano-whiskers (length: 500 nm).