Half-Heusler(HH)semiconductors with high valence band degeneracy are promising p-type thermoelectric(TE)materials.However,effective p-type doping in HH semiconductors remains challenging,hindering further the explorat...Half-Heusler(HH)semiconductors with high valence band degeneracy are promising p-type thermoelectric(TE)materials.However,effective p-type doping in HH semiconductors remains challenging,hindering further the exploration of high-performance p-type TE materials.In this work,we conduct first-principles calculations to identify the dominant native defects and potential p-type dopants in three representative HH compounds,e.g.,NbFeSb,NbCoSn,and ZrNiSn.Our findings reveal that 4d interstitials underline the p-type dopability.By systematically investigating the extrinsic doping at the three Wyckoff positions in NbFeSb,NbCoSn,and ZrNiSn,respectively,we highlight that the pinned Fermi level serves as an indicator of p-type dopability.The calculation results identify Hf as a p-type dopant in NbCoSn under the Co-poor condition,which is further validated by experiments.A significantly improved p-type TE performance is obtained in Hf-doped NbCoSn.These results could guide the dopant selection and experimental optimization of the p-type TE performance of HH semiconductors.展开更多
基金supported by the National Key Research and Development Program of China(No.2023YFB3809400)the National Natural Science Foundation of China(Nos.52471239,92163203,and U23A20553)+2 种基金the Natural Science Foundation of Zhejiang Province(No.LR25E020005)the Fundamental Research Funds for the Central Universities(No.226-2024-00075)the 111Project(no.B16042).
文摘Half-Heusler(HH)semiconductors with high valence band degeneracy are promising p-type thermoelectric(TE)materials.However,effective p-type doping in HH semiconductors remains challenging,hindering further the exploration of high-performance p-type TE materials.In this work,we conduct first-principles calculations to identify the dominant native defects and potential p-type dopants in three representative HH compounds,e.g.,NbFeSb,NbCoSn,and ZrNiSn.Our findings reveal that 4d interstitials underline the p-type dopability.By systematically investigating the extrinsic doping at the three Wyckoff positions in NbFeSb,NbCoSn,and ZrNiSn,respectively,we highlight that the pinned Fermi level serves as an indicator of p-type dopability.The calculation results identify Hf as a p-type dopant in NbCoSn under the Co-poor condition,which is further validated by experiments.A significantly improved p-type TE performance is obtained in Hf-doped NbCoSn.These results could guide the dopant selection and experimental optimization of the p-type TE performance of HH semiconductors.
