| Summary: | 碩士 === 義守大學 === 材料科學與工程學系碩士班 === 96 === Copper oxide thin films were prepared by spin coating. These thin films were obtained from the mixed 2M Cu(NO3)2 and 1M CuSO4 aqueous solutions, with different additives, 1M LiNO3 plus 1M Al(NO3)3, respectively. Through controlling different heat treatments, various pHs in the mixed solution, and some minor additives such as Li+ and Al3+, the formation mechanisms and physical properties of CuO and Cu2O were studied. From experimental results, it showed the optimal compositions for obtaining excellent CuO or Cu2O were located at the chemical precursors with 40 mol% CuSO4 + 60 mol% Cu(NO3)2, and pure Cu(NO3)2, and sintering temperature of these samples was at 900℃.
In the chemical precursor with pure Cu(NO3)2 system, the Cu2O phase was easily obtained in the sample with Al3+ additive after firing under the Ar atmosphere. In the same sintering conditions, sintered specimens with the Li+ additive only contained CuO, but not Cu2O. Except that, the intensity of Cu2O diffraction peak was increasing with the increasing amount of Al3+ in the sintered samples.
As to the microstructures before and after sintering, the morphologies of precipitate were highly agglomerated as the pH value in the initial solutions increased. However, after sintering, the morphologies of oxide films were gradually uniformly distributed for the specimens at high pHs. During heating cycle, the surface morphology of heat-treated thin film charged from agglomerated powder to fine particle, and further became a melter liquid to form a continuous, and defect-free flat surface. Most sintered spin-coated film containing Cu2O showed coral-like microstructure with nano-tuble. However, this type of microstructure was not observed in the sintered specimen containing CuO, and its surface morphology was block-like type.
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