Impurity Band Effects in Thermoelectric Materials
Impurity Band Effects in Thermoelectric Materials
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DOI：
10.1007/s11664-012-2108-4
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发表时间：
2012-08-01
影响因子：
2.1
通讯作者：
Goldsmid, H. J.
中科院分区：
文献类型：
--
作者：
Goldsmid, H. J.
考虑了引入杂质带改善功率因数的可能性。杂质带中载流子对塞贝克系数和电导率的贡献用费米能量和杂质能级相对于主带边缘的位置来表示。令人惊讶的是，发现杂质带的存在通常带来的好处很少，事实上，当它位于主带边缘附近时，功率因数可能会显着降低。我们的发现与观察结果一致，即PbTe的优点数字通过深层铊态的存在而得到改善。他们还指出，对于Bi2Te3，通过反掺杂对非化学计量的补偿可能不会产生最高的功率因数。
The possibility of improvement of the power factor through introduction of impurity bands is considered. The contributions to the Seebeck coefficient and electrical conductivity from carriers in an impurity band are expressed in terms of the Fermi energy and the position of the impurity levels relative to the edge of the main band. Surprisingly, it is found that the presence of an impurity band generally brings little benefit, and in fact, when it lies near the edge of the main band, the power factor may be significantly reduced. Our findings are consistent with the observation that the figure of merit of PbTe is improved by the presence of deep-lying thallium states. They also indicate that, for Bi2Te3, compensation for nonstoichiometry by counterdoping may not yield the highest power factor.