Realization of non-equilibrium process for high thermoelectric performance Sb-doped Ge Te

作     者：Evariste Nshimyimana Xianli Su Hongyao Xie Wei Liu Rigui Deng Tingting Luo Yonggao Yan Xinfeng Tang 

作者机构：State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology 

出 版 物：《Science Bulletin》 (科学通报（英文版）)

年 卷 期：2018年第63卷第11期

页      面：717-725页

核心收录：

学科分类：08[工学] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported by the National Natural Science Foundation of China(51402222,51521001,and 51632006) the 111 Project of China(B07040) 

主　　题：GeTe Sb doping MS-SPS process Thermoelectric properties 

摘      要：Pristine GeTe shows inferior thermoelectric performance around unit due to the large carrier concentration induced by the presence of intrinsic high concentration of Ge vacancy. In this study, we report a thermoelectric figure of merit ZT of 1.56 at 700 K, realized in Sb-doped GeTe based thermoelectric(TE)materials via combined effect of suppression of intrinsic Ge vacancy and Sb doping. The nonequilibrium nature during melt spinning process plays very important role. For one thing, it promotes the homogeneity in Ge_(1-x)Sb_xTe samples and refines the grain size of the product. Moreover the persistent Ge precipitated as impurity phase in the traditional synthesis process is found to be dissolved back into the GeTe sublattice, accompanying with a drastic suppression of Ge vacancies concentration which in combination with Sb electron doping significantly reduced the inherent carrier concentration in *** carrier concentration, approaching the optimum carrier concentration ～3.74 × 10^(-20) cm^(-3) and a high power factor of 4.01 × 10^(-3) W m^(-1)K^(-2) at 750 K are achieved for Ge_(0.98)Sb_(0.02) Te sample. In addition,the enhanced grain boundary phonon scattering by refining the grain size through melt spinning(MS)process, coupled with the intensified alloying phonon scattering via Sb doping leads to low thermal conductivity of 1.53 W m^(-1) K^(-1) at 700 K for Ge_(0.94) Sb_(0.06) Te sample. All those contribute to a high ZT value,representing over 50% improvement in the ZT value compared to the Sb free samples, which provides an alternative way for ultrafast synthesis of high performance GeTe based thermoelectric material.