| Summary: | 碩士 === 國立彰化師範大學 === 光電科技研究所 === 95 === The purpose of the current study was to find out the most suitable conditions for the even-synthesized and highly-stabilized ZnO powder through various treatments. The various treatments manipulated in the study were through Sol-Gel method to synthesize ZnO Nanocrystals in different heating rates, synthesizing time, and the adding amount of capping agent (PVP).Moreover, techniques such as XRD, SEM, TEM, PL were also included in the study to measure the structures, surface state, and optic properties of ZnO Nanocrystal.According to the results of XRD, the samples were with the Wurtzite structures, with the particle size ranging between 3 ~ 4 nm. As for SEM, the results showed that the ZnO secondary particles were aggregated particles, with the particle size ranging from 200 ~ 500 nm. The pictures of TEM also proved that the real size of secondary particles ranged between 3 ~ 4 nm, and they were gathered by ZnO Nanocrystals. Its exact size was in accordance with the one calculated by X-ray diffraction. In the PL measurement, crystals were unstable under the excite of He-Cd laser, and the PL property would changed and emission effectiveness was lowered as time went by. Both the quality of X-ray diffraction and emission effectiveness had significant promotion after the change of process variables such as the addition of capping agent, which redeemed its surface state.In the study of PL spectrum, the impurity bound exciton of ZnO QDS( ~ 7.5 nm) was found out to be 18.31meV, while the activation energy of it was 94.5meV. In addition, three equations, Vashni, O'Donnell, and Pässler were employed to fit the different bandgaps in different temperature of quantum dots, blocks, and nanoparticles. Therefore, the found parameters may provide help to the further studies on ZnO.
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