Mechanical and thermal processing effects on crystal defects and thermoelectric transport properties of Bi2(Se,Te)3 compounds
Mechanical and thermal processing effects on crystal defects and thermoelectric transport properties of Bi2(Se,Te)3 compounds
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DOI：
10.1016/j.jallcom.2013.03.190
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发表时间：
2013-09
影响因子：
6.2
通讯作者：
Meng-Pei Lu;C. Liao
中科院分区：
文献类型：
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作者：
Meng-Pei Lu;C. Liao
带电晶体缺陷通常起着电子给体或受体的作用，对碲化铋化合物的热电性能有很大的影响。本文研究了球磨、压制和热处理对Bi2(Se，Te)3化合物各种晶体缺陷布居和电/热输运性质的影响。研究发现，在机械球磨过程中，Bi2(Se，Te)3中引入了大量的施主Te空位，导致了较高的电子浓度和较低的载流子迁移率。为了提高Bi2(Se，Te)3化合物的热电功率因数，同时保持较低的热导率，通过调整晶体缺陷布居和载流子散射机制，提出了一种由压前和压后两步退火组成的两步退火法。
Charged crystal defects generally play the roles of electron donor or acceptor and affect thermoelectric properties of bismuth telluride compounds profoundly. In this study the effects of ball milling, pressing and thermal annealing on populations of various crystal defects and electrical/thermal transport properties of Bi2(Se,Te)3compounds are investigated. It has been found that abundant donor-type Te vacancies are introduced during mechanical milling process, leading to high electron concentration and reduced carrier mobility for cold-pressed Bi2(Se,Te)3. A two-step annealing method consisting of pre-press and post-press annealing is presented for improving thermoelectric power factor while retaining low thermal conductivity of Bi2(Se,Te)3compounds by tweaking crystal defect population and carrier scattering mechanism.