硅纳米线复合Mg2Si基热电材料的制备与性能研究

Fabrication and thermoelectric performance of the SiNWs-Mg2Si nanocomposite

摘要:

摘 要: 硅纳米线（SiNWs）是近年来研究较广泛的一种新型纳米半导体材料，因其优异的电热学性能而引起科研者的关注。采用纳米复合的方法，以硅纳米线作为其它块体热电材料掺杂改性的物相，理论上可显著降低材料晶格热导率且不严重损害其电性能，从而提高材料热电性能。本文利用溶液法混合粉体并通过电场激活压力辅助烧结（FAPAS）方法制备了不同硅纳米线含量的Mg2Si基复合热电材料，研究了硅纳米线的掺入及含量对基体材料热电性能的影响。结果表明：硅纳米线掺入后材料电导率大幅降低，塞贝克系数基本不变，热导率小幅降低。随着硅纳米线掺量增加，材料电导率降低，塞贝克系数稍有提高，热导率有升高趋势。硅纳米线掺量为0.1at%的样品在800K时ZT值达到最高值0.5。

Abstract:

Abstract: As a new kind of one-dimension thermoelectric materials, silicon nanowires(SiNWs) have been researched widely in recent years due to its excellent electrical and thermal properties. Theoretically, it is feasible to reduce the lattice thermal conductivity of bulk materials and keep its electrical conductivity as well by embedding SiNWs into the matrix as second phase. In this paper 2at% Bi doped SiNWs-Mg2Si powder was prepared by means of the solution method and consolidated subsequently, and the influence of silicon nanowires on the thermoelectric performance of the Bi-doped Mg2Si matrix was studied. It is indicated that the electrical conductivity of the materials decreased greatly, and the Seebeck coefficient remained roughly the same, and the thermal conductivity reduced a small amount. With the increase of the dosage of SiNWs, the electrical conductivity furtherly decreased, and the Seebeck coefficient slightly improved, and the thermal conductivity had a rising trend. The sample with 0.1at% SiNWs embedded obtained a highest ZT value of 0.5 at 800K.