Structural and thermoelectric properties of fine-grained Bi0.4Te3.0Sb1.6 thin films with preferred orientation deposited by flash evaporation method
Structural and thermoelectric properties of fine-grained Bi0.4Te3.0Sb1.6 thin films with preferred orientation deposited by flash evaporation method
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DOI：
10.1016/j.tsf.2007.12.130
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发表时间：
2008-07
期刊：
影响因子：
2.1
通讯作者：
M. Takashiri;K. Miyazaki;H. Tsukamoto
中科院分区：
文献类型：
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作者：
M. Takashiri;K. Miyazaki;H. Tsukamoto
研究了p型细晶Bi{sub 0.4}Te{sub 3.0}Sb{sub 1.6}薄膜的结构和热电性能。该膜通过闪蒸法沉积，并且在c轴方向上表现出优选的取向。通过优化沉积条件，我们可以获得表面清洁的薄膜。然后，为了提高具有优选取向的结晶度以及薄膜的热电性能，将它们在氢气环境中在大气压和200至350 ℃的温度下退火。C.用扫描电子显微镜和X射线衍射仪分别对薄膜的横截面结构和结晶度进行了研究。在室温下测量了电导率、塞贝克系数和热电功率因数。我们证实，晶粒生长和结晶沿着c轴的增强退火温度的增加。在本研究中观察到的p型Bi{sub 0.4}Te{sub 3.0}Sb{sub 1.6}薄膜的最高性能具有300 ℃的退火温度。在平均晶粒尺寸为88 nm时，热电功率因数为34.9 {mu}W cm{sup-1} K{sup-2}。我们认为合成条件减少了晶界和缺陷处潜在散射点的数量，从而提高了热电功率因数。
Structural and thermoelectric properties of p-type fine-grained Bi{sub 0.4}Te{sub 3.0}Sb{sub 1.6} thin films are investigated. The films are deposited by a flash evaporation method and exhibit a preferred orientation in the c-axis direction. By optimizing deposition conditions, we achieve thin films with clean surfaces. Then in order to enhance the crystallinity with preferred orientation, as well as the thermoelectric properties of the thin films, they are annealed in hydrogen ambient at atmospheric pressure and at temperatures ranging from 200 to 350 deg. C. The cross-section microstructure and crystallinity of the thin films are investigated by scanning electron microscopy and X-ray diffraction, respectively. The electrical conductivity, Seebeck coefficient, and thermoelectric power factor are measured at room temperature. We confirm that the grain growth and the crystallization along the c-axis are enhanced as the annealing temperature increases. The highest performance of p-type Bi{sub 0.4}Te{sub 3.0}Sb{sub 1.6} thin films observed in this study have an annealing temperature of 300 deg. C, resulting in a thermoelectric power factor of 34.9 {mu}W cm{sup -1} K{sup -2} at the average grain size of 88 nm. We consider that the synthesis conditions reduce the number of potential scattering sites at grain boundaries and defects, thus improving the thermoelectric power factor.