Positron Annihilation Study of Ternary Sb2Te3-xSex for Its Tuning Electrical and Thermal Properties
Positron Annihilation Study of Ternary Sb2Te3-xSex for Its Tuning Electrical and Thermal Properties
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三元 Sb2Te3-xSex 的正电子湮灭及其调节电学和热学性质的研究
DOI：
10.1007/s11664-016-5058-4
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发表时间：
2017
影响因子：
2.1
通讯作者：
Rui Xiong
中科院分区：
文献类型：
--
作者：
Wenwen Zheng;Dongwang Yang;Peng Bi;Chunqing He;Fengming Liu;Jing Shi;Yi Ding;Ziyu Wang;Rui Xiong
原子尺度的点缺陷在调节载流子浓度并最终影响电学和热学性质方面起着重要的作用。在这里，我们制备了三元Sb2Te3xSex合金，以研究内点缺陷与热电性能的密切关系。Sb2Te3晶格中Te原子的Se取代使电导率从2.29105 S/m降至6.49104S/m，原因是空穴浓度降低。下降的点缺陷，包括材料中的反位缺陷和空位，导致了载流子浓度的下降。三元Sb2Te3xSex的Seebeck系数随Se原子的掺杂而增大。同时，随着Se含量的增加，热导率呈下降趋势。结果表明，从相应的Sb2Te2.9Se0.1芯块开始，ZT值达到最大。正电子湮没测量表明，随着Se的加入，正电子平均寿命呈单调下降，表现为点缺陷的减少，这与热电性能一致。
Atomic scale point defects play important roles in tuning the carrier concentration and ultimately influencing electrical and thermal properties. Herein, we fabricated the ternary Sb2Te3xSex alloys to study the intimate relationship of internal point defects and thermoelectric performance. The Se substitution of Te atoms in the Sb2Te3 lattice decreased the electrical conductivity from 2.2 9 105 S/m to 6.4 9 104 S/m owing to the reduced holes concentration. The declined point defects, including antisite defects and vacancies in materials, gave rise to the decrease in carrier concentration. The Seebeck coefficient.of the ternary Sb2Te3xSex exhibited an increase with doping of Se atoms. Simultaneously, the thermal conductivity behaved a fallihg trend as well as increasing Se content. As a result, the ZT value reached the maximum from the corresponding Sb2Te2.9Se0.1 pellet. Positron annihilation measurement revealed that the average positron lifetime showed a monotonic decrease with Se addition, demonstrating the reduced point defects, which was in agreement with the thermoelectric performance.