| Summary: | 碩士 === 國立中山大學 === 電機工程學系研究所 === 104 === In this study, the Sb2Te3 thermoelectric thin films were deposited on polyimide substrates by thermal evaporation method. The effects of substrate temperature and Ag doping on the microstructures and thermoelectric properties of Sb2Te3 thin films were investigated. Besides, the annealing processes were carried out to investigate the characteristics of the thermoelectric films.
The structures of the thin films were analyzed by XRD and SEM, respectively. The thin films deposited at room temperature showed an amorphous phase. As the substrate temperature was increased, the XRD intensity of Sb2Te3 thin films increased and the defects and carrier mobility were reduced. Therefore, the Seebeck coefficient increased and the conductivity decreased at first. The optimized power factor of the Sb2Te3 p-type thin films was found to be about 3.57 μW/cmK2 at the substrate temperature of 125°C. For the Sb2Te3 thin films with Ag doping, the maximized value of power factor of 4.07 μW/cm·K2 could be obtained at the doping concentration of 5.37wt%, and the substrate temperature of 125°C.
After the thermal annealing processes, the results showed that the maximized value of power factor of 14.62 μW/cmK2 for undoped Sb2Te3 thin films could be obtained at substrate temperature of 125°C and annealing temperature of 250°C (60 minutes). In the Ag-doped Sb2Te3 thin films, the results showed that the maximized value of power factor of 10.24 μW/cmK2 could be obtained at substrate temperature of 125°C and annealing temperature of 200°C (60 minutes).
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