Synthesis of ZnO nanorods and nanorod arrays through hydrothermal methods

The ZnO nanorod clusters and arrays respectively have been prepared via simple hydrothermal method and CTAB-assisted hydrothermal method at 180°C by using zinc salts, metal zinc, hydrazine hydrate (N₂H₄·H₂O) and so on. The microstructures of the as-synthesized samples have been studied by means of X-ray diffraction, scanning electron microscope, field-emission scanning electron microscope and high-resolution transmission electron microscopes. The mean sizes of as-grown nanorods, which possess hexagonal structure, are about 40-80 nm in diameter. The formation of ZnO nanorod clusters or arrays and the importance of N₂H₄·H₂O are discussed with growth unit model of anion coordination polyhedra. Room-temperature photoluminescence spectra of as-grown samples show a strong UV emission, as well as various intensity blue-green emissions.