Synthesis And Characterization Of Different Morphology ZnO Nanomaterials

ZnO nanomaterials have attracted great attention at home and abroad in recent years,due to their important potential applications in solar cells, field effect transistors, gas sensors,biologic sensors, short-wave light emitting devices, short wave laser, and other aspects ofphotoelectric devices. Zinc oxide(ZnO) is an importantⅡ-Ⅵdirect wide band gap compoundsemiconductor material with a bandgap width(3.37ev), high exciton binding energy(60 meV) atroom temperature, whose excellent performance have been used in photoelectric devices,piezoelectric devices, thermal power devices, and other fields. Because the morphology andstructure of ZnO nano-materials have much effect on the properties and characteristics of thismaterial, recently, the researchers are committed to fabricate the special morphology ZnOnanostructure and have successfully synthesized ZnO nanostructures with different dimensionvarious morphologies, including to nano wires, nano rods, nano tubes, nano flowers , nanobelts by means of different methods.In this paper, we synthesized different morphologies of ZnO nanostructure by means ofsol-gel and chemical solution growth methods, whose morphologies have rod, sheet, flower,sphere. The morphology, structure, elemental compositions and performance of the ZnOnanostructures were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscope (TEM), the selected-area electron diffraction (SAED),energy dispersive X-ray spectrum (EDS), fourier transform infrared spectra (FTIR), Ultravioletabsorption spectroscopy(UV) and photoluminescence spectrum (PL).Finally, The formationmechanism of the special ZnO nanostructure were discussed. The main results are as follows:1. Synthesized one-dimensional ZnO nanorod arrays by sol-gel and chemical solutiongrowth methodsFirst, we have prepared ZnO seeds films on Ag-deposited glass substrates by sol-gelmethod. Based on the fabricated, zinc nitrate dihydrat (Zn(NO3)2 6H2O) and HMT were used asthe main materials, we have synthesized well-aligned and closely arranged ZnO nanorod arrays by chemical solution growth methods on the ZnO seed substrates. Results show that, the ZnOnanorods are single crystalline and have hexagonal wurtzite structure, average diameter is about100-300nm, long approximately is 2μm. The ZnO seeds films played a vital role in thewell-aligned growth of ZnO nanorod arrays, and the growth mechanism of ZnO nanorods wereillustrated at last.2. Fabricated two-dimensional ZnO nanosheets by chemical solution growth methodsWe successfully synthesized two-dimensional ZnO nanosheets by chemical solutiongrowth methods on Zn/Si(111)、ZnO/glass、Si(111) substrates. Testing results show that,fabricated ZnO nanosheets have hexagonal wurtzite structure and are single crystalline ZnO,thickness is about 50-100nm, the size of is about 1-2μm, distribution is interlaced. We comparedthat the different films have an effect on the morphology of ZnO nanosheets, analysed thegrowth mechanism of nanosheets.3. Synthesized 3-D flower-like ZnO nanostructures by sol-gel and chemical solutiongrowth methodsWe adopted a progress involved sol-gel and chemical solution growth methods to prepare3-D flower-like ZnO nanostructures on different substrates. Analysis indicated that theflower-like ZnO nanostructures consist of many hexagonal wurtzite structure and singlecrystalline ZnO nanorods, and have a strong broadband absorption in ultraviolet area, and PLspectrum has a strong blue emission at 421nm and two weak green emissions at 521nm and560nm. We analyzed the luminescence mechanism in detail. Finally we discussed the formationmechanism of the flower -like ZnO nanostructures.4. Prepared ZnO nanospheres by sol-gel methodZnO nanospheres were synthesized successfully by sol-gel method on glass substrates.SEM and TEM study shows ZnO nanospheres are composed of 20 to 30 nm polycrystalline ZnOnanoparticles. PL spectrum at room temperature exist a strong ultraviolet emission peak at398nm and a very sharp blue light peak at 482 nm, and a wide green light peak at 500 nm. Itsluminous mechanism and the formation mechanism of the ZnO nanospheres are discussedbriefly.