Vapor-phase Synthesis, Characterization And Physics Properties Of Quasi-one-dimensional Nanomaterials

Research on one-dimensional nanostructure has been one of the most important fields and focus of nanomaterials because of their contribution to the understanding of the basic concepts and potential technological applications. One-dimension nanostructure are ideal systems for investigation the dependence of electrical transport, optical properties and mechanical properties on size and dimensionality. They are expected to play an important role as both interconnects and functional components in the fabriction of nanoscale electronic and optoelectronical devices. The successful syntheses of one-dimension nanomaterials are the foundation to research on the properties of one-dimension nanomaterials. Based on the comprehensive analysis of fabrication methods of one-dimension nanostructures and combined with the present conditions in our laboratory, we focused on the synthesis of :(1) Znic oxide nanowires , tetragonal znic oxide and znic sulfide by simple physics evaporation, and the properties and characterization of them have been measured and analyzed. (2) MgS-ZnS core-shell nanoconstructure by two-step method and the characterization of the product. (4) silicon oxide nanowires by soften template method and the characterization of the product.The content of the thesis listing as follows:1. znic oxide nanowires and tetragonal znic oxide nanostructure have been fabricated by simple evaporation znic oxide powder and metallic znic. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations reveal that these nanowires are uniform diameter. The Raman spectra demonstrate that broaden and asymmetry peak in large wave-number caused by effect of lattice dilatation.2.znic sulfide nanowires doped with Au have been synthesized by CVD method at the present of Au film. SEM and TEM observations reveal that the nanowires are uniform. The higher synthesis temperature caused the lager diameter. Also the denser vapor caused the rougher nanowires' surface. EDS spectra demonstrate that Au existed in the nanowire body. This phenomenon suggests that Au atom was doped into nanowires. PL measurement shows that the nanowires have emission peaks at 446nm and 520nm,respectively.(3) MgS-ZnS core-shell nanostructure have been synthesized by two-step CVDmethod. SEM and TEM observation reveal that the diameter of nanowire diminished during the process of reaction with Mg evaporation. The core of nanocable is single crystal znic sulfide and the shell of nanocable is polycrystalline MgS.(4) silicon oxide nanowires have been synthesized by heating mixture of metal Ga and Si powder. The dissolvability of Si diminishes with the drop of temperature. The low melt metal Ga serves as the soft template for the growth of silicon oxide. PL investigation shows that the nanowires have two strong emission peaks at 420nm and 480nm and relative weak peak at 804nm, respectively. The former two emission peaks may caused by defect center such as silicon vacancy. What caused 804nm peak is unknown.With all above work related to the synthesis of one-dimension nanostructures, we get some progress in the fabrication science and technology of one-dimension nanomaterials.