Tao Qirui, Deng Rigui, Li Junjie, Yan Yonggao, Su Xianli, Poudeu Pierre F P, Tang Xinfeng
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
Laboratory for Emerging Energy and Electronic Materials (LE3M), Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States.
ACS Appl Mater Interfaces. 2020 Jun 10;12(23):26330-26341. doi: 10.1021/acsami.0c03225. Epub 2020 May 29.
Cd-containing polycrystalline BiSbTe samples with precisely controlled phase composition were synthesized by conventional melting-quenching-annealing technique and a melt-spinning method. The pseudo ternary phase diagram for Cd-Bi/Sb-Te in the region near BiSbTe was systematically studied. Cd serves as an acceptor dopant contributing holes, whereas for samples doped with CdTe, the combined effects of the substitution of Sb/Bi with Cd and the formation of Sb/Bi antisite defects leads to the increase in hole concentration. Moreover, upon doping with Cd, the lattice thermal conductivity decreases significantly owing to the intensified point defect phonon scattering. The sample with Cd content of 0.01 attains the maximum of 1.15 at 425 K. The utilization of melt-spinning method brings about the in situ nanostructured CdTe and grain size refinement, which further reduce the lattice thermal conductivity while preserving excellent electrical performance. As a result, a higher of 1.30 at 425 K is realized with CdTe content = 0.005.
通过传统的熔融淬火退火技术和熔体纺丝法合成了具有精确控制相组成的含镉多晶BiSbTe样品。系统研究了BiSbTe附近区域Cd-Bi/Sb-Te的伪三元相图。Cd作为受主掺杂剂提供空穴，而对于掺杂CdTe的样品，Cd取代Sb/Bi以及形成Sb/Bi反位缺陷的综合作用导致空穴浓度增加。此外，掺杂Cd后，由于点缺陷声子散射增强，晶格热导率显著降低。Cd含量为0.01的样品在425 K时达到最大值1.15。熔体纺丝法的应用实现了原位纳米结构的CdTe和晶粒细化，在保持优异电学性能的同时进一步降低了晶格热导率。结果，CdTe含量为0.005时，在425 K时实现了更高的1.30。
