Preparation Of ZnO Nanostructure Via A Hydrothermal Etching Of Zinc Foil And The Study Of Its Photoluminescence Behavior

Zinc oxide is a new direct and wide band gap ofâ…¡-â…¥group semiconductor material. For its semiconductor features and unique nature from nanodimensional, zinc oxide nano-materials shows great potential application in the field of LCD displays, solar cells, water treatment, protective coatings, gas sensing components, solid-state lighting and UV light emitting devices. In recent decades, although the effort had been made to the preparation of ZnO nano materials, there are still many problems to be solved. At present, effective control of morphology, structure, optical properties for ZnO nano materials is the investigation focus.In this paper, the morphology control and photoluminescence of ZnO nanostrucutres are the main research object. Low-temperature clean hydrothermal method was used for the preparation of ZnO nanomatrieals with rod-like, tube-like, pencil-like and flower-like morphology and some influencing factors of ZnO morphology. Structure and properties were studied including temperature, reaction time and so on. Finally, different morphologies of nano-ZnO microstructures and phase composition were characterized by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. The optical properties of nano-ZnO were tested by fluorescence spectroscopy. The main contents of this paper could be summarized as follows:1. A facile synthesis method was devolped for the preparation of ZnO nanostructure with low energy consumption. Only water and zinc foil were used as the starting materials for the preparation of ZnO nano structures with rod-like, tube-like, pencil-like andflower-like morphologie in the absence of any surfactants. The results showed that all samples are the hexagonal structure and two factors of reaction time and temperature played key roles in the control of crystallization and their morphologies for ZnO nanostructures. Room temperature photoluminescence (PL) spectra results showed that the samples possessed two emission peaks:one emission peak was at about 392nm in the ultraviolet region; the other was a relatively weak one at about 532nm in the green area. In addition, some samples were also found to have a blue emission peak with central wavelength at about 473nm.2. A kind of PVP/ZnO composite nanostructure was obtained. Sheet-like ZnO nanostructures with hexagonal blende structure were prepared by the hydrothermal etching of Zn foil using PVP as the surfactant, whose room temperature PL spectra only showed a strong UV emission peak at 380nm without other emission peaks. A possible reason for the photoluminescence behavior was speculated to be from the fact PVP was favorable to the improvement of ZnO nanostructure crystalline, and thus, high quality ZnO nanostructures without defects were obtained.3. The self-supporting ZnO nanostructure arrays were obtained. ZnO nanostructures arrays supported with ZnO foil was prepared by subsequent low temperature annealing of the remaining zinc. With the increase of annealing time, the grain sizes were found to be enhanced gradually. The PL intensity was firstly increased and then decreased. The enhanced PL intensity at the initial step should be from the improved crystalline due to the annealing, while the forthcoming reduction of PL intensity was believed to be from the large number of defects generated from the giant stress generated during the oxidation of Zn foil.