Sn1−xGexTe的高温高压合成及热电性能

周绪彪; 李尚升; 李洪涛; 宿太超; 杨曼曼; 杜景阳; 胡美华; 胡强

doi:10.11858/gywlxb.20210805

Sn_1−xGe_xTe的高温高压合成及热电性能

doi: 10.11858/gywlxb.20210805

1.
河南理工大学材料科学与工程学院，河南焦作　454000
2.
中华人民共和国上海海关，上海　200135

基金项目: 河南省高等学校青年骨干教师培养计划（2018GGJS057）；中华人民共和国海关总署科研计划项目（2019HK014）

详细信息

作者简介:
周绪彪（1998－），男，硕士研究生，主要从事热电材料研究. E-mail：124423641@qq.com

通讯作者:
李尚升（1966－），男，博士，副教授，主要从事超硬及多功能材料研究. E-mail：lishsh@hpu.edu.cn

中图分类号: O521.2
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出版历程
- 收稿日期: 2021-05-30
- 修回日期: 2021-06-15

Synthesis and Thermoelectric Properties of Sn₁₋_xGe_xTe by High Temperature and High Pressure

1.
Institute of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, Henan, China
2.
Shanghai Customs District P.R.China, Shanghai 200135, China

摘要

摘要: 在众多热电材料中，SnTe具有与PbTe相同的晶体结构且不含重金属Pb，近年来引起了人们的广泛关注。目前，本征SnTe的热电性能并不特别优异，存在以下问题：大量本征Sn空位导致载流子浓度过高，从而降低了电输运性能；价带中的轻带与重带能量劈裂较大，且带隙过窄，不利于通过重带参与电运输提高Seebeck系数；晶格热导率较大。利用高温高压方法快速合成了Ge掺杂的SnTe合金，系统研究了不同Ge含量对SnTe的微观结构和热电性能的影响。结果表明：Ge掺杂能够有效地调控SnTe材料的电运输性能；Ge掺杂使样品的微观结构发生变化，样品晶粒细化，且析出纳米第二相，晶界和纳米相对声子的散射作用降低了热导率；样品Ge_0.2Sn_0.8Te在700 K时的热电优值达到0.35。
- 热电材料 /
- 高压 /
- SnTe
Abstract: In many thermoelectric materials, SnTe has the same crystal structure as PbTe, but does not contain heavy metal Pb, which has attracted extensive attention in recent years. At present, the thermoelectric properties of intrinsic SnTe are not particularly excellent. There are some disadvantages: a large number of intrinsic Sn vacancies lead to high carrier concentration, which worsens the electrical transport performance; the energy splitting between the light band and the heavy band in the valence band is large and the band gap is too narrow, which is not conducive to the Seebeck coefficient participating in the electrical transport through the heavy band; the lattice thermal conductivity is large. In this study, SnTe doped with Ge was prepared under high pressure and high temperature conditions. The results show that the band structure and the electrical transport properties of SnTe can be tuned effectively by Ge doping. At the same time, Ge doping can modulate the microstructure of the SnTe, which induced the formation of fine grains and second nanophases then reduced the thermal conductivity. The maximum figure-of-merit is 0.35 at 700 K for Ge_0.2Sn_0.8Te.
- thermoelectric /
- high pressure /
- SnTe

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图 1 高压合成Ge_xSn_1−xTe样品的XRD谱

Figure 1. XRD patterns of Ge_xSn_1−xTe synthesized under high pressure

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图 2 高压合成的Ge_xSn_1−xTe的SEM图像：(a) x = 0，(b) x = 0.1，(c) x = 0.2，(d) x = 0.3

Figure 2. SEM patterns of Ge_xSn_1−xTe synthesized under high pressure: (a) x = 0, (b) x = 0.1, (c) x = 0.2, (d) x = 0.3

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图 3 SnTe (a)和Ge_1/3Sn_2/3Te (b)的能带结构

Figure 3. Band structures of SnTe (a) and Ge_1/3Sn_2/3Te (b)

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图 4 Ge_xSn_1−xTe的热电性能：(a) Seebeck系数，(b) 电阻率，(c) 热导率，(d) 品质因子

Figure 4. Electrical properties of Ge_xSn_1−xTe: (a) Seebeck coefficient, (b) resistivity, (c) thermal conductivity, (d) quality factor

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