Abstract
Bi 2 (Te 1-x Se x ) 3 is an important kind of n-type thermoelectric material. In this study, interfacial reactions at 250 °C in the Sn/Bi 2 Te 3 , Sn/Bi 2 Se 3 and Sn/Bi 2 (Te 1-x Se x ) 3 couples are examined. In the Sn/Bi 2 Te 3 couple, the reaction zone is found to be non-planar and the reaction path is liquid/(liquid + SnTe)/Bi 2 Te 3 . But with only 2.0 at.%Se addition to the Bi 2 Te 3 substrate, very different reaction results are observed. In the Sn/Bi 2 (Te 1-x Se x ) 3 couple, the reaction layers are planar, and the reaction path is liquid/SnTe/BiTe x /Bi 2 (Te 1-x Se x ) 3 . In the Sn/Bi 2 Se 3 couple, the reaction layers are also planar, the reaction path is liquid/SnSe/BiSe/Bi 2 Se 3 , and the Bi content in the SnSe phase varies. The growth rates in the Sn/Bi 2 Te 3 couples are very fast, and the reaction layer is as thick as 1174 μm in just 15 min. Very dramatic reduction of growth rates has been observed with Se addition to the substrates, and the reaction layer is only 9 μm in the Sn/Bi 2 (Te 2.9 Se 0.1 ) couples after reaction for 30 min. © 2014 Elsevier B.V. All rights reserved.