Te和Y共掺杂提高n-Mg_(3.2)Sb_(1.5)Bi_(0.5)热电性能的研究  

Improvement of Thermoelectric Properties of n-Mg_(3.2)Sb_(1.5)Bi_(0.5) by Co-doping of Te and Y

作　　者：强宇 康泽鹏 陈少平[2] 樊文浩 JIANG Yu;KANG Zepeng;CHEN Shaoping;FAN Wenhao(College of Physics and Optoelectronic Engineering,Taiyuan University of Technology,Taiyuan 030024,China;College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学物理与光电工程学院,太原030024 [2]太原理工大学材料科学与工程学院,太原030024

出　　处：《太原理工大学学报》2023年第2期257-263,共7页Journal of Taiyuan University of Technology

基　　金：国家自然科学基金资助项目(51775366,51875387,52072104);山西省科学基金资助项目(201801D121017,201901D1111116)。

摘　　要：Mg_(3)Sb_(2)材料是优秀的中温区热电材料,具有极低的热导率,然而其载流子浓度偏低。通过机械合金化法结合放电等离子烧结(SPS)技术制备n型Mg_(3.2)Y_(0.05)Sb_(1.5)Bi_(0.5)Teδ样品,并研究了其热电传输性能。结果表明阴离子位掺杂元素Te可以进一步提高阳离子位掺杂的Mg_(3.2)Y_(0.05)Sb_(1.5)Bi_(0.5)材料的载流子浓度。载流子浓度从5.02×10^(19)cm-3增加到9.76×10^(19)cm-3,接近理论预测的最佳值,同时功率因子也从10.89μW·K^(-2)·cm^(-1)提高到15μW·K^(-2)·cm^(-1).此外,Te元素进入晶格后,材料的晶格热导率也有大幅的降低,从0.92 W·m^(-1)·K^(-1)降低到0.68 W·m^(-1)·K^(-1).载流子浓度最高的样品在750 K时zT峰值可达1.6,在300~750 K温度范围内的平均zT值可达1.0.本工作证明阳离子和阴离子位共同掺杂对Mg_(3)Sb_(1.5)Bi_(0.5)载流子浓度提高的效果优于单阳离子或单阴离子位掺杂,该掺杂方法有望应用到其它的热电材料性能的优化中。Mg_(3)Sb_(2)material is an excellent thermoelectric material in the mid-temperature region, with extremely low thermal conductivity, but its carrier concentration is low. In this paper, n-type Mg_(3.2)Y_(0.05)Sb_(1.5)Bi_(0.5)5Teδsamples were prepared by mechanical alloying method combined with spark plasma sintering(SPS) technology, and their thermoelectric transport properties were investigated. The results show that the anion site doping element Te can further increase the carrier concentration of the cation site doped Mg_(3.2)Y_(0.05)Sb_(1.5)Bi_(0.5)material. The carrier concentration is increased from 5.02×10^(19)to 9.76×10^(19)cm^(-3), and the power factor is also improved from 10.89 to 15 μW·K^(-2)·cm^(-1). In addition, after Te element enters the lattice, the crystal thermal conductivity of the material is also greatly reduced, from 0.92 to 0.68 W·m^(-1)·K^(-1). The sample with the highest carrier concentration has a peak zT of 1.6 at 750 K, and an average zT of 1.0 in the temperature range of 300-750 K. This work proves that the co-doping of cations and anions is better than single-cation or single-anion doping for increasing the carrier concentration of Mg_(3)Sb_(1.5)Bi_(0.5). This doping method is expected to be applied to the optimization of other thermoelectric materials.

关 键 词：Mg_(3)Sb_(2) 载流子浓度 Te元素 N型半导体 热电性能 

分 类 号：O472[理学—半导体物理]