Hydrothermal Synthesis Of ZnO Nanostructures And Characterization

Zinc oxide is Ⅱ-Ⅵ semiconductor materials. ZnO have a wide direct band gap of3.37eV and a large exciton-binging energy of60meV at room temperature. ZnO has broadapplication prospects in many areas for its catalytic, electrical, optoelectronic andpiezoelectric properties. ZnO is widely used in LED, LCD displays, solar cells, gas sensors,varistors, surface acoustic wave devices, etc. Recently, many researchers have successfullyaccomplished a variety of zinc oxide nanostructures. These structures play an important rolein the preparation of optoelectronic devices. Therefore, how to controll the morphology andthe size of ZnO and to lower industrial production costs are the key points. This thesis mainlystudies the controllability of ZnO nanostructures by adopting hydrothermal method. Due to itssimple equipment, low growth temperature, controllability of morphology and size, thehydrothermal method has been widely used to prepare ZnO thin film in laboratory.This thesis adopts hydrothermal method to grow ZnO nanostructures. We use scanningelectron microscopy, X-ray diffraction and PL spectra techniques to characterize the samples.Firstly, we synthesize the well-aligned ZnO nanorods on Si substrate. The average length ofZnO nanorods is5μm and the diameter of nanorods is about400nm. The results of XRDindicate that ZnO nanorods have good crystal quality. And the PL spectra shows that theyhave excellent optical properties. Secondly, we synthesize the well-aligned ZnO nanotaperson FTO substrate. The average length of nanotapers is6μm. The results of XRD show thatthey have good crystal quality. And the PL spectra certifies that they have good opticalproperties. Finally, we adopt one step hydrothermal method for preparing ZnO nanorods onthe FTO substrate. SEM shows that the average length of nanorods is only3~4μm, thediameter is also fine. This thesis also discusses the principle of homogeneous nucleation.