Microstructure and thermoelectric properties of Ga-DOPED SiGe alloys prepared by mechanical alloying and induction hot pressing
Microstructure and thermoelectric properties of Ga-DOPED SiGe alloys prepared by mechanical alloying and induction hot pressing
复制标题
机械合金化和感应热压制备Ga-DOPED SiGe合金的显微组织和热电性能
DOI：
10.1142/s1793604714500088
复制
发表时间：
2014-04-01
影响因子：
1.3
通讯作者：
Chen, Xiaoyuan
中科院分区：
文献类型：
--
作者：
Lin, Shanshan;Wang, Chunlin;Chen, Xiaoyuan
采用高能球磨-感应热压法制备了Ga掺杂SiGe合金。随着球磨时间的增加，晶粒尺寸急剧减小，球磨2-12 h后，晶粒尺寸在3-500 nm范围内呈现纳米结构特征。由干磨2 h和6 h粉末热压而成的块体合金由不同成分的微米至纳米SiyGe 100-y组成，其中Ga优先位于亚微米和纳米级富Ge相中并形成调制掺杂结构。湿磨12 h后的粉末经热压处理后，其显微组织和成分更加均匀。性质表征表明，虽然Ga掺杂导致p型导电，只有部分Ga原子作为掺杂剂掺入SiGe固溶体相中。干磨2小时和6小时的粉末热压而成的样品具有较高的功率因子，而湿磨12小时的粉末热压而成的样品具有低得多的热导率。对于具有标称组成Si 80 Ge 18 Ga 2的6小时干磨和热压样品，在805 ℃下的最大品质因数（ZT）为0.51。
Ga-doped SiGe alloys were prepared by high energy ball milling followed by induction hot pressing. The grain size decreases dramatically with increasing mill time, and nanostructured features in the range 3-500 nm were introduced after extensive ball milling for 2-12 h. The bulk alloys hot pressed from 2 h and 6 h dry-milled powders consist of different compositions of micron-to nanosized SiyGe100-y, where Ga prefers to locate in the submicron-and nanosized Ge-rich phase and form a modulation-doping structure. The samples hot pressed from 12 h wet-milled powders are more homogeneous in microstructure and composition. Property characterization shows that although Ga-doping leads to p-type conduction, only part of Ga atoms is incorporated as dopant in the SiGe solid solution phase. Samples hot pressed from 2 h and 6 h dry-milled powders have higher power factors, while those hot pressed from 12 h wet-milled powders posses much lower thermal conductivity. The maximum figure of merit (ZT) is 0.51 at 805 degrees C for the 6 h dry-milled and hot pressed sample with the nominal composition Si80Ge18Ga2.