N型In-Se基半导体的结构与热电转换特性
发布时间：2019-02-21 11:52
【摘要】：Ag In Se2作为一种典型的I III VI2黄铜矿结构化合物,其中存在固有的阴阳离子缺陷对(2V-1Ag+In2+Ag)。选择Zn原子替代其中Ag原子,Zn原子会占位在Ag或者In的晶格位置,从而产生多种反结构缺陷,例Zn Ag1+和Zn In1-缺陷,分别成为施主和受主。这些缺陷对材料的能带结构和输运性能会产生很大的影响,从而调控热电性能。α?In2Se3是一种层状结构半导体化合物,其中存在1/3 In原子层空位并有少量未成键的Se原子,这同样对优化结构和热电性能具有巨大的潜力。本文研究了Ag1-x In Znx Se2(x=0.025,0.05,0.1),In2-x Znx Se3(x=0.005,0.01,0.02)两种材料,具体研究成果总结如下:1、根据化学计量比设计制备Ag1-x In Znx Se2(x=0.025,0.05,0.1),采用X射线粉末衍射结合GSAS结构精修原子占位情况。通过精修,发现Zn原子占据在In原子和Ag原子的位置几率基本相同。在815 K,且x=0.01时,材料Ag1-x In Znx Se2(x=0.1)的ZT值为1.05±0.12,远远高于本征Ag In Se2。2、采取同样的方法制备In2-x Znx Se3(x=0.005,0.01,0.015,0.02)化合物,并对其进行晶体结构和热电性能研究。实验发现Zn有插层到In2Se3中Se-Se层(van der waals)间隙的迹象,但尚需进一步证实。这一插层降低了载流子跨越层隙的阻力,极大地提高了电导率。同时,插层还使晶格结构发生严重畸变,降低了晶格热导率。通过热电性能测试分析,在垂直于压制方向,当x=0.01、温度为917K时,热电优值ZT取得最大值0.75,为本征α-In2Se3的3.27倍;而平行于压制方向,热电优值ZT取得最大值1.22,约为本征α-In2Se3的5.0倍。因而,研究得出,Zn的掺入大大改善了α-In2Se3的热电性能。
[Abstract]:Ag In Se2 is a typical structural compound of III VI2 chalcopyrite, in which there are inherent anion defect pairs (2V-1Ag In2 Ag). The Ag atom is replaced by the Zn atom, and the Zn atom will occupy the lattice position of the Ag or In, resulting in a variety of anti-structural defects. For example, the Zn Ag1 and Zn In1- defects become the donor and the acceptor, respectively. These defects have a great influence on the energy band structure and transport properties of the materials, thus regulating the thermoelectric properties. A? In2Se3 is a layered semiconductor compound with a third of the In atom layer vacancy and a small amount of unbonded Se atoms. It also has great potential for optimizing structure and thermoelectric performance. In this paper, two kinds of materials, Ag1-x In Znx Se2 and In2-x Znx Se3, have been studied. The results are summarized as follows: 1. According to the stoichiometric design, Ag1-x In Znx Se2 was prepared by means of X-ray powder diffraction and GSAS structure refinement. By refinement, it is found that the probability of Zn atoms occupying the positions of In atoms and Ag atoms is almost the same. At 815K, the ZT value of the material Ag1-x In Znx Se2 (xC0. 1) is 1. 05 卤0. 12, which is much higher than that of the intrinsic Ag In Se2.2, which uses the same method to prepare the In2-x Znx Se3 compound (xK0. 005, 0. 01, 0. 015 ~ 0. 02). The crystal structure and thermoelectric properties were studied. It is found that Zn intercalates the (van der waals) gap of Se-Se layer in In2Se3, but it needs further confirmation. This intercalation reduces the resistance of carriers to cross the layer gap and greatly increases the conductivity. At the same time, the intercalation also leads to the serious distortion of the lattice structure and reduces the lattice thermal conductivity. Through the thermoelectric performance test and analysis, when the temperature is 917K, the maximum value of ZT is 0.75, which is 3.27 times that of the intrinsic 伪-In2Se3, perpendicular to the pressing direction, when XG is 0.01 and the temperature is 917K. Parallel to the pressing direction, the maximum value of thermoelectric ZT is 1.22, which is about 5.0 times of the intrinsic 伪-In2Se3. Therefore, the study shows that the incorporation of Zn greatly improves the thermoelectric properties of 伪-In2Se3.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304
本文编号：2427472
[Abstract]:Ag In Se2 is a typical structural compound of III VI2 chalcopyrite, in which there are inherent anion defect pairs (2V-1Ag In2 Ag). The Ag atom is replaced by the Zn atom, and the Zn atom will occupy the lattice position of the Ag or In, resulting in a variety of anti-structural defects. For example, the Zn Ag1 and Zn In1- defects become the donor and the acceptor, respectively. These defects have a great influence on the energy band structure and transport properties of the materials, thus regulating the thermoelectric properties. A? In2Se3 is a layered semiconductor compound with a third of the In atom layer vacancy and a small amount of unbonded Se atoms. It also has great potential for optimizing structure and thermoelectric performance. In this paper, two kinds of materials, Ag1-x In Znx Se2 and In2-x Znx Se3, have been studied. The results are summarized as follows: 1. According to the stoichiometric design, Ag1-x In Znx Se2 was prepared by means of X-ray powder diffraction and GSAS structure refinement. By refinement, it is found that the probability of Zn atoms occupying the positions of In atoms and Ag atoms is almost the same. At 815K, the ZT value of the material Ag1-x In Znx Se2 (xC0. 1) is 1. 05 卤0. 12, which is much higher than that of the intrinsic Ag In Se2.2, which uses the same method to prepare the In2-x Znx Se3 compound (xK0. 005, 0. 01, 0. 015 ~ 0. 02). The crystal structure and thermoelectric properties were studied. It is found that Zn intercalates the (van der waals) gap of Se-Se layer in In2Se3, but it needs further confirmation. This intercalation reduces the resistance of carriers to cross the layer gap and greatly increases the conductivity. At the same time, the intercalation also leads to the serious distortion of the lattice structure and reduces the lattice thermal conductivity. Through the thermoelectric performance test and analysis, when the temperature is 917K, the maximum value of ZT is 0.75, which is 3.27 times that of the intrinsic 伪-In2Se3, perpendicular to the pressing direction, when XG is 0.01 and the temperature is 917K. Parallel to the pressing direction, the maximum value of thermoelectric ZT is 1.22, which is about 5.0 times of the intrinsic 伪-In2Se3. Therefore, the study shows that the incorporation of Zn greatly improves the thermoelectric properties of 伪-In2Se3.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304
【参考文献】
相关期刊论文 前1条
1 姜洪义;Effects of Solid-State Reaction Synthesis Processing Parameters on Thermoelectric Properties of Mg_2Si[J];Journal of Wuhan University of Technology-Materials Science;2004年02期
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