Effect of grain size on thermoelectric properties of n-type nanocrystalline bismuth-telluride based thin films
Effect of grain size on thermoelectric properties of n-type nanocrystalline bismuth-telluride based thin films
复制标题
DOI：
10.1063/1.2990774
复制
发表时间：
2008-10-15
影响因子：
3.2
通讯作者：
Tsukamoto, H.
中科院分区：
文献类型：
--
作者：
Takashiri, M.;Miyazaki, K.;Tsukamoto, H.
研究了晶粒尺寸对n型碲化铋基纳米晶薄膜热电性能的影响。我们制备的纳米晶薄膜的平均晶粒尺寸为10，27，和60 nm的闪蒸方法，然后通过氢退火过程。在室温下测量热电性能，即通过微分3 Ω法的热导率、电导率和塞贝克系数，并用于评价品质因数。当平均晶粒尺寸为10 nm时，最小热导率为0.61 W m（-1）K-1。我们还估计了纳米晶薄膜的晶格热导率，并将其与晶界上声子散射的简化理论进行了比较。对于纳米晶粒，纳米薄膜的晶格热导率随着晶粒尺寸的减小而迅速减小，与理论计算结果相一致。品质因数也随着晶粒尺寸的减小而减小，这归因于晶界处缺陷数量的增加。(C)2008年美国物理学会。[DOI 10.1063/1.2990774]
The effect of grain size on the thermoelectric properties of n-type nanocrystalline bismuth-telluride based thin films is investigated. We prepare the nanocrystalline thin films with average grain sizes of 10, 27, and 60 nm by a flash-evaporation method followed by a hydrogen annealing process. The thermoelectric properties, in terms of the thermal conductivity by a differential 3 omega method, the electrical conductivity, and the Seebeck coefficient are measured at room temperature and used to evaluate the figure of merit. The minimum thermal conductivity is 0.61 W m(-1) K-1 at the average grain size of 10 nm. We also estimate the lattice thermal conductivity of the nanocrystalline thin films and compare it with a simplified theory of phonon scattering on grain boundaries. For nanosized grains, the lattice thermal conductivity of nanocrystalline thin films decreases rapidly for smaller grains, corresponding to the theoretical calculation. The figure of merit is also decreased as the grain size decreases, which is attributed to the increased number of defects at the grain boundaries. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.2990774]