Ge掺杂n型Sn基VIII型单晶笼合物的制备及热电传输特性

摘要

采用Sn自熔剂法制备了具有n型传导的VII型Ba8Ga16-xGexSn30(06 x 61.0)单晶笼合物，并对其结构和热电特性进行研究.研究结果表明：Ge在单晶中的实际含量较少，随着掺杂量的增加样品的晶格常数略有减小， Ge掺杂后样品的载流子浓度较掺杂前低，迁移率增加；所有样品的Seebeck系数均为负值，且绝对值较未掺杂样品低，但Ge掺杂后样品的电导率提高了62%；x=0.5的样品在500 K附近取得最大ZT 值1.25.%Single crystalline samples of type-VII Ba8Ga16-xGexSn30 (0 6 x 6 1.0) clathrates are fabricated by the Sn flux method. The structures and thermoelectric properties of the samples at temperatures ranging from 300 to 600 K are studied. Research results show that the actual content of Ge is relatively small in single crystal. The lattice parameters of the samples decrease slightly with the increase of the doping composition of Ge. The Ge doped samples have lower carrier density and higher carrier mobility than undoped samples. The Seebeck coefficients of all the doped samples are negative, and their absolute values are smaller than those of the undoped one. However, the electrical conductivity of the sample is increased by 62%after doping Ge and the sample of x=0.5 obtains a maximum value of ZT (1.25) at about 500 K.