Synthesis And Character Of ZnO Nanorod/Nanotube Arrays And Polymorphic Nanomaterials

As an important â…¡-â…£ semiconductor, zinc oxide (ZnO) is of considerable interest owing to its distinguished performance in electronics, optics, mechanics, and acoustics. ZnO with a band gap of 3.37 eV and large exciton binding energy of 60 meV at room temperature is a key technological material. Recent research has demonstrated that the creation of ZnO nanostructures in highly oriented and ordered arrays is of crucial importance for the development of novel nanodevices (e.g. short wave laser and Grartzel solar cells electrode). Especially, since the first report of ultraviolet lasing from ZnO nanowires (nanorods) at room temperature, substantial effort has been devoted to the development of novel synthetic methodologies for highly oriented and ordered ZnO nannowires (nanorods) arrays. Moreover, polymorphic nanomaterials (ZnO nanobelts, nanoneedles and nanoflowers) are of great importance because of their great potential for testing and understanding fundamental concepts and application. High-quality vertical ZnO nanowire arrays are grown using epitaxy, heteroepitaxy usually need expensive substrates (e.g.sapphire, monocrystalline silicon) and require expensive equipments and high temperature. Homoepitaxy with a textured ZnO thin film that is deposited on top of a nonepitaxial substrate (such as silicon or glass) to act as a nanowire nucleation layer.Solution approaches are appealing because of their simple equipment, low cost and good potential for scale-up. Here, ZnO nanowires, nanorods, nanotubes and polymorphic nanomaterials were synthesized by a simple solution method. The morphologies, phase structure and the photoluminescence properties of the prepared products were investigated by field emission scanning electron microscopy (FE-SEM), X-ray diffractometer (XRD), transmission electron microscope (TEM) and photoluminescence (PL) spectrum. The main contents of our work are as follows:1. Synthesis of oriented ZnO nanowire arrays using ZnO films as seedsThe high aspect ratio and oriented ZnO nanowire arrays were synthesized on a glass subatrate that coated with ZnO seeds film in an aqueous solution of zinc nitrate hydrate (Zn(NO₃)₂) and hexamethylenetetramine (HMT; (CH₂)₆N₄). And the effect of pretreatment of ZnO seeds film on the morphology of ZnO arrays was studied.2. Synthesis of ZnO nanorod arrays and rocket nanostructure using TiO₂ films as...