Microstructure and contact resistivity of (Bi, Sb)2Te3/Sb interface

Thermoelectric joint composed of Bi0.5Sb1.5Te3 (BiSbTe) material and antimony (Sb) metallic interlayer was fabricated by Spark Plasma Sintering. The reliability of the joints was investigated by interfacial microstructure evolution using electron probe micro-analysis for the samples with different accelerated isothermal aging time. After aging for 30 days in vacuum, the thickness of diffusion layer is about 50 mu m. Sb2Te3 was identified to be the major interfacial compound. The contact resistivity, depending on the thickness of interfacial compound, is 3 x 10(-6) ohm cm(2) before aging and increases to 8.5 x 10(-6) ohm cm(2) after aging for 30 days. The contact resistivity of thermoelectric material/Sb interface is very small as compared to that of solder alloys as interlayer. This study provides a new interlayer-Sb to be used in the bismuth telluride based thermoelectric module.