Enhancing the thermoelectric figure of merit through the reduction of bipolar thermal conductivity with heterostructure barriers
Enhancing the thermoelectric figure of merit through the reduction of bipolar thermal conductivity with heterostructure barriers
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DOI：
10.1063/1.4892653
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发表时间：
2014-08-04
影响因子：
4
通讯作者：
Shakouri, Ali
中科院分区：
文献类型：
--
作者：
Bahk, Je-Hyeong;Shakouri, Ali
在本文中，我们从理论上提出，当少数载流子被异质结构势垒选择性阻挡时，通过抑制双极热导率，可以显著提高具有小禁带的半导体材料在本征掺杂区域附近的热电优值。这一方案在纳米材料中特别有效，在纳米材料中，晶格热导率因边界上声子散射的增加而降低，因此包括双极项的电子热导率限制了优值系数zT。结果表明，当晶格热导率低至0.3W/mK时，p型PbTe的ZT可以提高到3以上，n型PbTe的ZT可以在900K和少数载流子阻断下提高到2以上。
In this paper, we present theoretically that the thermoelectric figure of merit for a semiconductor material with a small band gap can be significantly enhanced near the intrinsic doping regime at high temperatures via the suppression of bipolar thermal conductivity when the minority carriers are selectively blocked by heterostructure barriers. This scheme is particularly effective in nanostructured materials where the lattice thermal conductivity is lowered by increased phonon scatterings at the boundaries, so that the electronic thermal conductivity including the bipolar term is limiting the figure of merit zT. We show that zT can be enhanced to above 3 for p-type PbTe, and above 2 for n-type PbTe at 900 K with minority carrier blocking, when the lattice thermal conductivity is as low as 0.3 W/m K. (C) 2014 AIP Publishing LLC.