磷掺杂硅锗合金热电材料的高压合成及热电性能

Enhanced Thermoelectric Performance of P-Doped Silicon-Germanium Alloys Synthesized by High-Pressure Method

热电材料是一种可以实现热能与电能相互转换的功能材料,硅锗合金作为优良的高温热电材料被应用于深空探测。采用高压合成法制备了磷掺杂n型SiGe合金Si_(80)Ge_(20)P_(x)(x=0,1,2),研究了其电输运和热输运特性。结果表明,高压合成样品具有多尺度缺陷。磷掺杂可以优化SiGe合金的电导率和Seebeck系数,1050 K时Si_(80)Ge_(20)P_(1)样品的功率因子较未掺杂样品提升了100%。同时,掺磷量的增加导致晶格热导率下降,1050 K时Si_(80)Ge_(20)P_(2)样品的热导率降低约80%。此外,Si_(80)Ge_(20)P_(x)的热电性能得到显著提升,1050 K时Si_(80)Ge_(20)P_(2)样品的热电优值达到1.1。

Thermoelectric material is a kind of functional material which could realize the conversion between thermal energy and electric energy.Silicon-germanium(SiGe)alloy is used in deep space exploration as a kind of high temperature thermoelectric material.In this work,P-doped n-type SiGe alloy was prepared by high pressure synthesis method.The electrical and thermal transport properties of Si_(80)Ge_(20)P_(x)(x=0,1,2)were characterized.The results show that the samples synthesized under high pressure have multiscale defects.P-doping could optimize the electrical conductivity and Seebeck coefficient of SiGe alloy,the power factor of Si_(80)Ge_(20)P_(1) sample is 100%higher than that of the undoped sample at 1050 K.Furthermore,the increase of P content leads to the decrease of lattice thermal conductivity,and the thermal conductivity of Si_(80)Ge_(20)P_(2) sample decreases by about 80%at 1050 K.The thermoelectric properties of SiGe alloy are significantly improved,and the maximum figure of merit of Si_(80)Ge_(20)P_(2) sample reached 1.1 at 1050 K.