Extrinsic doping of the half-Heusler compounds
Extrinsic doping of the half-Heusler compounds
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DOI：
10.1088/0957-4484/27/33/334002
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发表时间：
2016-08-19
期刊：
影响因子：
3.5
通讯作者：
Madsen, Georg K. H.
中科院分区：
文献类型：
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作者：
Stern, Robin;Dongre, Bonny;Madsen, Georg K. H.
控制p型和n型掺杂是提高热电材料功率因数的关键手段。在本工作中，我们提供了半赫斯勒化合物的缺陷热化学的详细了解。我们计算了n型TiNiSn和p型TiCoSb热电材料中本征和外征缺陷的形成能。它显示了在线存储库的合并如何减少这些计算中的工作量。在TiNiSn中，我们发现Ni-和ti -间隙缺陷对TiNiSn载流子浓度起着至关重要的作用。此外，我们发现外源掺杂Sb可以显著提高载流子浓度，这与实验结果一致。对于TiCoSb，我们发现Sc-Ti， Fe-Co和Sn-Sb是可能的p型掺杂剂。虽然实验工作主要集中在Sb位的sn掺杂，但目前的结果强调了在所有晶格位上p掺杂TiCoSb的可能性。
Controlling the p- and n-type doping is a key tool to improve the power-factor of thermoelectric materials. In the present work we provide a detailed understanding of the defect thermochemistry in half-Heusler compounds. We calculate the formation energies of intrinsic and extrinsic defects in state of the art n-type TiNiSn and p-type TiCoSb thermoelectric materials. It is shown how the incorporation of online repositories can reduce the workload in these calculations. In TiNiSn we find that Ni- and Ti-interstitial defects play a crucial role in the carrier concentration of TiNiSn. Furthermore, we find that extrinsic doping with Sb can substantially enhance the carrier concentration, in agreement with experiment. In case of TiCoSb, we find Sc-Ti, Fe-Co and Sn-Sb being possible p-type dopants. While experimental work has mainly focussed on Sn-doping of the Sb site, the present result underlines the possibility to p-dope TiCoSb on all lattice sites.