Proceedings of Engineering and Technology Innovation (Jul 2019)
Hydrothermally Grown ZnO Nanoflowers on a Template-Assisted Ordered Seed Array
Abstract
1-D nanostructure arrays recently attract much attention because of their unique optical, structural, and electronic properties in the field of materials science, microelectronics, and optoelectronic engineering. Zinc Oxide (ZnO) nanoflowers were synthesized by a facile hydrothermal method on a template-assisted deposited ZnO seed array. The ZnO thin film was prepared via a sol-gel spin-coating process on a concave sapphire substrate first. Then an Al layer and an optically clear resin film were individually deposited on the ZnO thin film. After a lift-off process, a convex ZnO seed array film was formed. Finally, ZnO nanoflowers were synthesized by the hydrothermal method at 90oC for 10 to 60 min. The structural, morphological and optical properties of the ZnO nanoflowers were investigated. The XRD results indicate that the ZnO nanoflowers were polycrystalline with a hexagonal wurtzite-type structure with a (002) preferential orientation. The FE-SEM micrographs exhibited the diameter and length of ZnO nanorods increased with the increasing growth time from 10 to 60 min. The 105-nm diameter and 1150-nm length nanorods were obtained with 60-min growth time. Photoluminescence spectra showed a sharp emission peak (IUV) at approximately 380 nm and its intensity increased with the growth time. A weak emission band (IVIS) at 450–550 nm was also observed and the IUV/IVIS increased with the growth time. This result indicates that the defects were reduced and the crystal quality was enhanced with the growth time. The prepared ZnO nanoflowers can be applied to various optoelectronic and sensing devices.
