| Summary: | 碩士 === 長庚大學 === 光電工程研究所 === 101 === Due to its unique properties, including high electron mobility, wide and direct bandgap and large exciton binding energy, Zinc oxide (ZnO) nanostructures have been considered promising candidates for optoelectronic and microwave device applications. Although the fabrication of well defined nanostructures is far-reaching, it is surmised that the development of techniques for preparation of micro-ZnO with novel microstructures would be most salient in the near future. In this work, ZnO crystals were grown on a Si substrate by the hydrothermal method using an aqueous solution of zinc nitrate (Zn(NO3)2) and ammonium hydroxide (NH3OH). Careful adjustment of the amount of ammonia can considerably facilitate to organize the highly ordered ZnO nanostructures. In order to investigate the symmetry properties in response to the change in the nanostructures, measurements of X-ray diffraction (XRD), scanning electron microscope (SEM) and temperature-dependent photoluminescence (PL) were performed on the samples. With adjustment of ammonia concentration in the solution, the morphologies of the obelisk, flower-like, homocentric bundles, and nanorod ZnO were observed by SEM. As far as the group properties of the samples studied were concerned, the correlation between the PL and the invariant theory were investigated as a function of temperature by examining the luminescent intensity, full-width at half-maximum (FWHM) , and thermal activation energy.
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