| Summary: | 碩士 === 國立清華大學 === 化學工程學系 === 95 === The present research focuses on the preparation and applications of the one-dimensional (1-D) nanostructures of cadmium selenide (CdSe) and zirconium dioxide (ZrO2) fabricated via the vapor phase based deposition processes. First, for the preparation of the CdSe nanowires, we developed a PVD process with the VLS growth mechanism. SEM, XRD, TEM, PL, and UV-vis analyses were conducted and the plausible growth mechanism of the 1-D CdSe nanowires was proposed and discussed. Second, for the application of the cadmium selenium nanowires, a low molar ratio of Mn was doped into the CdSe nanowires to produce CdSe based diluted magnetic semiconductor (DMS) nanowires. The Mn content (0.4、0.8 and 1.4 mol%) was found to affect the magnetic property of the present DMS nanostructure. For example, the blocking temperature (TB) and the coercivity of the ferro-
magnetism state increase with increasing Mn doping concentration. For the preparation of ZrO2 nanorod array, we developed an MOCVD process. When the furnace temperature was above 700℃,the monoclinic and tetragonal phases would both exist in the product nanorod array. Lastly, the additive Y2O3 was doped into the ZrO2 nanorod array to prepare yttria-stabilized-zirconia (YSZ) nanorod arrays. The Y content of 0.8(monoclinic)、13(tetragonal)、20 and 45 mol % was determined by TEM-EDS. The oxygen ion conductivity of the YSZ nanorod array with Y2O3 content of 10 mol% is only 18-31% for the empirical equation 8- YSZ nano-powders because the activation energy of the YSZ nanorod array is larger than the empirical equation. The more compact YSZ nanorod structure, the compact sinter between Pt electrode and YSZ nanorod structure and optimal co-doping system can be used to improve the oxygen ion conductivity in the future.
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