深圳大学学报理工版

采用熔炼-淬火-高能球磨-放电等离子体烧结工艺,制备GeTe-PbTe合金Ge0.75Pb0.25Te及Se替代合金Ge0.75Pb0.25Te0.5Se0.5,研究和比较它们的物相、微结构及热电性能. 结果表明:母合金Ge0.75Pb0.25Te由分别以GeTe和PbTe为基的两相组成, 具有调幅分解组织,而Se替代合金Ge0.75Pb0.25Te中50%Te的合金变成以GeTe为基的单一固溶体,且存在大量的较小孪晶组织,两种合金都表现为p型半导体导电特性,固溶的Pb和Se原子改善了化合物的载流子浓度及能带结构,导致合金的Seebeck系数大幅度增加,固溶的Se及Pb原子、孪晶组织和晶界形成多尺度的声子散射中心,导致合金具有极低的热导率,热电优值ZT大幅度提高,673 K下,从Ge0.75Pb0.25Te的0.45提高到Ge0.75Pb0.25Te0.5Se0.5的1.6.

The alloy Ge0.75Pb0.25Te and its Se substitution alloy Ge0.75Pb0.25Te0.5Se0.5 were prepared by reaction melting, quenching, high-energy ball milling and spark plasma sintering techniques. The phases, microstructures and thermoelectric properties for both alloys were investigated. Experimental results show that the alloy Ge0.75Pb0.25Te consists of both GeTe-based and PbTe-based phases with spinodal decomposition microstructures while the Se substitution alloy Ge0.75Pb0.25Te0.5Se0.5 is of the GeTe-based solid solution single phase with a lot of twinning microstructures. The alloys show a nature of p-type conduction. The solute Pb and Se atoms in the lattice modify the band structure of the compounds, leading to a considerable increase in Seebeck coefficient. The solute Pb and Se atoms, twinning microstructures and grain boundaries form panoscopic phonon scattering centers, result in an extremely low thermal conductivity of the alloy and a dramatic increase of its figure of merit ZT from 0.45 for the alloy Ge0.75Pb0.25Te to 1.6 for the alloy Ge0.75Pb0.25Te0.5Se0.5 at 673 K.

引言
1 背景介绍
2 实验方法
3 结果与讨论
4 结语

图1 Ge0.75Pb0.25Te(两相)及Ge0.75Pb0.25Te0.5Se0.5(单相)合金XRD 图谱<br/>Fig.1 Powder XRD patterns for the alloys Ge0.75Pb0.25Te(two phases)and

图1 Ge0.75Pb0.25Te(两相)及Ge0.75Pb0.25Te0.5Se0.5(单相)合金XRD 图谱
Fig.1 Powder XRD patterns for the alloys Ge0.75Pb0.25Te(two phases)and

图2 Ge0.75Pb0.25Te 合金XRD结构精修图<br/>Fig.2 Rietveld refinement for the XRD pattern of alloy Ge0.75Pb0.25Te

图2 Ge0.75Pb0.25Te 合金XRD结构精修图
Fig.2 Rietveld refinement for the XRD pattern of alloy Ge0.75Pb0.25Te

图3 Ge0.75Pb0.25Te合金的调幅分解微结构及元素线扫描<br/>Fig.3 Spinodal decomposition microstructures and EDX line scanning for Ge, Pb and Te elements of Ge0.75Pb0.25Te alloy

图3 Ge0.75Pb0.25Te合金的调幅分解微结构及元素线扫描
Fig.3 Spinodal decomposition microstructures and EDX line scanning for Ge, Pb and Te elements of Ge0.75Pb0.25Te alloy

图4 Ge0.75Pb0.25Te0.5Se0.5的孪晶组织及其电子衍射<br/>Fig.3 Twining microstructures and SAED along [11^-0] zone axis of Ge0.75Pb0.25Te0.5Se0.5 alloy

图4 Ge0.75Pb0.25Te0.5Se0.5的孪晶组织及其电子衍射
Fig.3 Twining microstructures and SAED along [11^-0] zone axis of Ge0.75Pb0.25Te0.5Se0.5 alloy

图5 Ge0.75Pb0.25Te及Se替代合金Ge0.75Pb0.25Te0.5Se0.5热电性能比较<br/>Fig.5 Comparison on the thermoelectric properties for the alloys Ge0.75Pb0.25Te and Ge0.75Pb0.25Te0.5Se0.5

图5 Ge0.75Pb0.25Te及Se替代合金Ge0.75Pb0.25Te0.5Se0.5热电性能比较
Fig.5 Comparison on the thermoelectric properties for the alloys Ge0.75Pb0.25Te and Ge0.75Pb0.25Te0.5Se0.5

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备注

引言

1 背景介绍

2 实验方法

3 结果与讨论

4 结语

期刊信息

备注

引言

1 背景介绍

2 实验方法

3 结果与讨论

4 结 语

期刊信息

4 结语