Thermoelectric properties of n-type nanocrystalline bismuth-telluride-based thin films deposited by flash evaporation
Thermoelectric properties of n-type nanocrystalline bismuth-telluride-based thin films deposited by flash evaporation
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DOI：
10.1063/1.2717867
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发表时间：
2007-04
影响因子：
3.2
通讯作者：
M. Takashiri;M. Takiishi;Saburo Tanaka;K. Miyazaki;H. Tsukamoto
中科院分区：
文献类型：
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作者：
M. Takashiri;M. Takiishi;Saburo Tanaka;K. Miyazaki;H. Tsukamoto
采用差分3ω法研究了n型碲化铋纳米晶薄膜（Bi2.0Te2.7Se0.3）的室温热导率。采用闪蒸法在玻璃衬底上生长纳米晶薄膜，然后在250℃下进行氢退火。利用原子力显微镜、x射线衍射和能量色散x射线光谱学研究了薄膜的结构。薄膜的平均晶粒尺寸为60 nm，平面导热系数为0.8 W / m k，并研究了薄膜的面内电导率和面内塞贝克系数。假设薄膜的面内导热系数与横面方向的导热系数相同，则薄膜的面内优值估计为ZT=0.7。与平均晶粒尺寸为30 μm且成分与薄膜基本相同的烧结体样品相比，纳米晶薄膜的性能降低了约50%。
The thermal conductivity of n-type nanocrystalline bismuth-telluride-based thin films (Bi2.0Te2.7Se0.3) is investigated by a differential 3ω method at room temperature. The nanocrystalline thin films are grown on a glass substrate by a flash evaporation method, followed by hydrogen annealing at 250 °C. The structure of the thin films is studied by means of atomic force microscopy, x-ray diffraction, and energy-dispersive x-ray spectroscopy. The thin films exhibit an average grain size of 60 nm and a cross-plane thermal conductivity of 0.8 W∕m K. The in-plane electrical conductivity and in-plane Seebeck coefficient are also investigated. Assuming that the in-plane thermal conductivity of the thin films is identical to that of the cross-plane direction, the in-plane figure of merit of the thin films is estimated to be ZT=0.7. As compared with a sintered bulk sample with average grain size of 30 μm and nearly the same composition as the thin films, the nanocrystalline thin films show approximately a 50% redu...