Effect of Vacancy Distribution on the Thermal Conductivity of Ga2Te3 and Ga2Se3
Effect of Vacancy Distribution on the Thermal Conductivity of Ga2Te3 and Ga2Se3
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DOI：
10.1007/s11664-010-1479-7
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发表时间：
2011-01
影响因子：
2.1
通讯作者：
Chang-Eun Kim;K. Kurosaki;M. Ishimaru;H. Muta;S. Yamanaka
中科院分区：
文献类型：
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作者：
Chang-Eun Kim;K. Kurosaki;M. Ishimaru;H. Muta;S. Yamanaka
本课题组将注意力集中在Ga2Te3作为天然纳米结构热电材料上。Ga_2Te_3基本上具有锌钛矿结构，但由于Ga和Te之间的价态失配，三分之一的Ga位是结构空位。已经证实，（1）Ga2Te3中的空位作为二维（2D）空位平面存在，并且（2）Ga2Te3表现出出乎意料的低热导率（κ），这很可能是由于2D空位平面的高效声子散射。然而，二维空位平面的尺寸和周期性对κ的影响尚不清楚。此外，还不清楚是否只有2D空位平面降低κ，或者点型空位是否也可以降低κ。在本研究中，我们试图通过控制退火条件来制备具有不同空位分布的Ga_2Te_3和Ga_2Se_3。通过透射电子显微镜表征样品的原子结构，并通过激光闪光法测量的热扩散率评估κ。讨论了空位分布对Ga_2Te_3和Ga_2Se_3的κ的影响。
Our group has focused attention on Ga2Te3as a natural nanostructured thermoelectric material. Ga2Te3has basically a zincblende structure, but one-third of the Ga sites are structural vacancies due to the valence mismatch between Ga and Te. It has been confirmed that (1) vacancies in Ga2Te3exist as two-dimensional (2D) vacancy planes, and (2) Ga2Te3exhibits an unexpectedly low thermal conductivity (κ), most likely due to highly effective phonon scattering by the 2D vacancy planes. However, the effect of the size and periodicity of the 2D vacancy planes onκhas been unclear. In addition, it has also been unclear whether only the 2D vacancy planes reduceκor if point-type vacancies can also reduceκ. In the present study, we tried to prepare Ga2Te3and Ga2Se3with various vacancy distributions by controlling annealing conditions. The atomic structures of the samples were characterized by means of transmission electron microscopy, andκwas evaluated from the thermal diffusivity measured by the laser flash method. The effects of vacancy distributions onκof Ga2Te3and Ga2Se3are discussed.