Abstract
Bi 2 (Se 0.1 Te 0.9 ) 3 and Ni are the most commonly used N-type thermoelectric material and barrier layer in commercial thermoelectric modules. This study systematically examines the interfacial reactions between Ni and Bi 2 (Se 0.1 Te 0.9 ) 3 and its constituent material systems. Results related to the interfacial reactions between Ni/Se and Ni/Bi 2 Se 3 are not available in the literature, and are reported for the first time in this study. The reaction phases in the solid/solid Ni/Bi, Ni/Se, Ni/Bi 2 Te 3 and Ni/Bi 2 (Se 0.1 Te 0.9 ) 3 couples are NiBi 3 , α-Ni 3 Se 2 and Ni 1-x Se, NiTe 2 and (Bi 2 ) m (Bi 2 Te 3 ) n , and NiTe 2 and (Bi 2 ) m (Bi 2 Te 3 ) n , respectively. The reaction phases in the solid/solid Ni/Te and Ni/Bi 2 Te 3 couples evolve with reaction time. Respectively, they are NiTe 2 and Bi-oversaturated Ni 1-x Se phase in the early stage of reaction, and become Ni 3 Te 2 , NiTe 0.775 and NiTe 2 , and NiBi 3 and Ni 1-x Se phases with longer reaction time. The Ni/Te reaction rate is slower compared with those of Ni/Bi and Bi/Se, yet the dominant reaction phase is the NiTe 2 phase in both the Ni/Bi 2 Te 3 and Ni/Bi 2 (Se 0.1 Te 0.9 ) 3 couples.