| Summary: | 碩士 === 國立中正大學 === 化學工程研究所 === 102 === This study was to investigate the properties of three-dimensional Bi2Te3-based thin films prepared by potentiostatic electrodeposition technique onto three-dimensional polystyrene templates which were formed on stainless steel substrates via blade coating method. Temperature were fixed at 30oC and agitated at a speed of 340 rpm during electrodeposition process. A hot pressing-annealing method was applied after electroplating process to enhance thermoelectric properties. In order to obtainthe optimal operational conditions, these films were used for electrochemical, compositional and thermoelectrical analysis. It was found that p-type Bismuth-Antimony-Telluride and n-type Bismuth-Telluride-Selenium thin films which were deposited at a constant potential of -0.2V and -0.06V vs. Ag/Ag Clare the closest to ideal composition. The thermoelectrical analysis results show that both Seebeck coefficient and electrical resistivity were reduced after hot pressing treatment. That could be attributed to the raising pressure and temperature which forced atoms to rearrange during hot pressing-annealing process. The treatment will further reduce the lattice defects and make structure tighter. Although thermal conductivity would also increased by this phenomenon but it is almost disproportionate compared to electrical resistivity drop, and the Seebeck coefficient decreases. The carrier concentration and mobility presented down ward and upward trend respectively with processing time extend. In terms of performance, the maximum power factorof the films studies is 555μW/K2m for p-type Bismuth-Antimony-Telluride and 397μW/K2m forn-type Bismuth-Telluride-Selenium. Both of these two samples were prepared under the conditions of 290oC and 195kgf/cm2 after current assisted hot pressing-annealing treatment for 60 min.
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