Preparation Of Zno Bouquet-like Whiskers And Nanorods With The Morphology Control

ZnO is a new generational multifunctional II -VI compound semiconductor with a wide and direct band gap. ZnO nanostructures show great promising applications in opto-electric devices, surface acoustic wave devices, piezoelectricity materials, field emitters, sensors, ultraviolet Lasers, solar cells and so on.In this dissertation, ZnO nano-material with diversity of structures and morphologies, including nanorod clusters, rod-like whiskers, needle-like whiskers and multi-pod-needle-like whiskers, and whisker/nanorod arrays ZnO, were obtained via a simple hydrothermal route by using zinc salts (or znic) and hydrazine hydrate (N2H4 H2O) at various conditions. The formation of ID ZnO nanorod or whisker clusters is discussed with growth unit model of anion coordination polyhedra. Our results show that all ZnO obtianed possess hexagonal wurtzite structure identified by XRD. The formation of ZnO nucleus can be controlled by Na2SeO4 as oxidant and the single-rod-like ZnO whiskers have been synthiesized via this strategy. In the solution, N2H4 acts as OH" supplier, complex and reducing agent. The concentration of N2H4 -H2O strongly affects the state of zinc cation in the precursors solution, which results in the changes of the solution uniformity and physical-chemistry conditions, and ulteriorly affects the morphologies of as-grown ZnO. Temperature and holding times have different effects on ZnO morphologies at various conditions. Organic solvent can shield the faces of ZnO crystals. Surfactant is important factor of controlling morphologies of synthesized ZnO, which changed the form of the growth unit and has great effects on the process of ZnO nucleus and the properties of ZnO crystal faces. Room-temperature photoluminescence spectra of the ZnO samples show a strong V-UV emission as well as a blue-green emission.