| Summary: | 碩士 === 淡江大學 === 物理學系碩士班 === 103 === We have performed x-ray absorption near edge structure (XANES) to study Ni doped thermoelectric CoSb3. Co and Ni L3 - edge XANES results indicate that there is a charge transfer from Ni 3d to Co 3d orbitals. The charge transfer, which increases with Ni concentration, may have provided more conduction electrons to the system resulting an increased electronic conductivity. Also observed is that, at low doping concentration, the number of Co 3d unoccupied states are correlated with thermopower. In addition, we have study a series of CoSb3 samples sintered at 540°C, 560°C and 580°C. Our results indicate that the Co 3d unoccupied states and the conductivity decrease with increasing sintering temperature. Sintering temperature over 560°C CoSb3 becomes n-type semiconductor, and the number of Co 3d unoccupied states are correlated with thermopower.
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