Mg掺杂n型Sn基VIII型单晶笼合物的结构及电传输特性  

Structural and electrical transport properties of Mg-doped n-type Sn-based type VIII single crystalline clathrate

作　　者：孟代仪 申兰先[1] 李德聪[2] 晒旭霞[1] 邓书康[1] 

机构地区：[1]可再生能源材料先进技术与制备教育部重点实验室太阳能研究所云南师范大学,昆明650500 [2]云南开放大学光电工程学院,昆明650500

出　　处：《物理学报》2014年第17期277-282,共6页Acta Physica Sinica

基　　金：国家自然科学基金研究项目(批准号:51262032)资助的课题~~

摘　　要：本文采用Sn自熔剂法,制备Mg掺杂Sn基单晶笼合物Ba8Ga16-XMgXSn30(0 X 1.5),并对其结构及电传输性能进行研究.结果表明所制备化合物为具有空间群Iˉ43m的VIII型单晶笼合物,随Mg掺杂量的增加,对应化合物的熔点略有升高,晶格常数减小,掺杂样品中填充原子Ba的实际含量低于理想值8.0,其在十二面体空洞中的占有率约为0.93(Mg的名义含量X=1.5时).所有样品均表现为n型传导,Mg的掺入对材料的能带结构有一定影响,Mg掺杂后,样品的载流子浓度降低,Seebeck系数的绝对值、电阻率增加,Mg的名义含量X=1.5时,样品的功率因子在430 K附近取得最大值1.26×10-3W·m-1·K-2.Mg-doped Sn-based single crystalline samples BasGa16-xMgxSn30（0 ≤ X ≤ 1.5） were grown from Sn flux to characterize their structural and electrical transport properties. Research results show that the prepared compounds are well indexed by the type-VIII clathrate structure with a space group I4- 3m. With the increase in Mg content, the melting point of the corresponding compounds increases. On the contrary, the lattice constant decreases. The actual content of filling atomic Ba in doped samples is below the ideal value of 8.0, the occupancy of Ba in the dodecahedron is about 0.93 for the sample with X = 1.5. All the samples show n-type conduction. The Mg atoms have an effect on the band structure of the materials, and the carrier concentrations in the doped samples are reduced. However, the absolute values of Seebeck coefficient and the resistivity of doped compounds increase, respectively. By calculation, the sample of X =1.5 obtains the maximum value of power factor 1.26 ×10-3 W.m-1.K-2 near 430 K.

关 键 词：VIII型笼合物 n型传导 单晶 

分 类 号：O483[理学—固体物理]