Promising defect thermoelectric semiconductors Cu1-xGaSbxTe2 (x = 0-0.1) with the chalcopyrite structure
Promising defect thermoelectric semiconductors Cu1-xGaSbxTe2 (x = 0-0.1) with the chalcopyrite structure
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DOI：
10.1039/c2ta00157h
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发表时间：
2013-01-01
影响因子：
11.9
通讯作者：
Zhou, Hong
中科院分区：
文献类型：
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作者：
Cui, Jiaolin;Li, Yapeng;Zhou, Hong
通过计算在CuGaTe2中适当添加Sb的缺陷黄铜矿半导体Cu1-xGaSbxTe2的能带结构，我们证明Sb实际上主要占据Te而不是Cu晶格位置。这种占主导地位的占据增加了费米能级的态密度（DOS）和价带的有效质量，从而导致塞贝克系数的增加。当 x < 0.1 时，由于空穴简并态下浓度 n 和迁移率 mu 的细微变化，电导率 (sigma) 与 Sb 含量几乎没有关系。尝试添加 Sb 会导致晶格热导率 (kappa(L)) 降低，但随着 Sb 含量的增加，kappa(L) 的增强有限。因此，我们确定了其机制，提出对 kL 的双重影响是由额外的晶格失配和晶体结构畸变引起的。通过考虑上述所有对输运特性的影响，我们在 721 K 下获得了 Cu1-xGaSbxTe2 (x = 0.02) 样品的最高热电 ZT 值 (1.07 +/- 0.1)，这显示了在中间温度下应用的前景。
Through calculating the band structures of the defect chalcopyrite semiconductor Cu1-xGaSbxTe2 with the proper addition of Sb to CuGaTe2, we have demonstrated that Sb actually mostly occupies the Te rather than Cu lattice sites. Such a dominant occupation increases the density of states (DOS) at the Fermi level and the effective mass of the valence band, and thereby results in an increase in the Seebeck coefficient. The electrical conductivity (sigma) is hardly related to Sb content when x < 0.1, due to the subtle change in the concentration n and mobility mu at the degenerate state of holes. The attempted addition of Sb causes a decrease in the lattice thermal conductivity (kappa(L)), but as the Sb content increases there is a limited enhancement of kappa(L). We have thus determined the mechanism, proposing that the dual effect on the kL resulted from the extra lattice mismatch and crystal structure distortion. By considering all the effects mentioned above on the transport properties, we have attained the highest thermoelectric ZT value (1.07 +/- 0.1) of the sample Cu1-xGaSbxTe2 (x = 0.02) at 721 K, which shows promise for application in the intermediate temperatures.