Fabrication Of Al Doped ZnO Micro-Nanosturctures And Their Photocatlytic Activities

The research of semiconductor nanomaterials has been attracting great attention due to their unique physical and chemical properties and promising applications in nanodevices. ZnO is a wide direct band gap semiconductor material that has good optoelectronic and piezoelectric dual properties. It has many potential applications in room-temperature （RT） ultraviolet laser, light-emitting diodes, sensors, transducers, biomedical sciences and photocatalysis. Therefore, ZnO nanostructures with different dimensions have been extensively studied. Recently, two-dimensional （2D） and （3D） nanomaterials with high surface areas and large pore volumes have been studied by some research groups. The aim of this work is to prepare 2D and 3D ZnO semiconductor nanostructures by effective hydrothermal process. Our works and results are as follows:1. The controlled synthesis of 2D Al³⁺ doped ZnO hexagonal nanoplates was achieved via a facile one-step hydrothermal approach. The morphologies and RT PL properties of nanoplates are derived from characterization by scanning electron microscopy and photoluminescence spectroscopy, respectively. The thicknesses of nanoplates can be controlled by Al³⁺ concentration. The photoluminescence spectra clearly showed blue-shift with the increasing of Al³⁺ content. Meanwhile, the resonant Raman spectrum of samples was measured by RT. The observation of multiple LO phonon scattering indicates the high crystalline quality of 2D ZnO nanoplates.2. We exploit a simple one-step hydrothermal approach to directly ZnO nanorod array on Al-doped ZnO nanoplate surface, free of template, surfactant, and pretreated substrates. A two-stage nucleation-growth process should account for the assembly process. We have studied the effects of Al³⁺ on the morphology of sample. The photoluminescence mechanism of the sample is discussed.3. The porous flower-like ZnO nanostructures which exhibited the high surface area and high production was synthesized by the hydrothermal method. The influence of different atmosphere on the photocatalytic systems of the final samples was studied. We have also analyzed the characteristics of flower-like ZnO nanostructures annealed in three different ambients: nitrogen gas, oxygen gas and air by XPS and PL spectra in details.