Electric properties of Ni/n-PbTe and Ni/p-Pb0.5Sn0.5Te joined by plasma activated sintering

In order to fabricate PbTe thermoelectric elements, Ni electrodes were joined with n-PbTe and p-Pb0.5Sn0.5Te by plasma activated sintering (PAS). The characterization of the Ni/n-PbTe and Ni/p-Pb0.5Sn0.5Te junctions was carried out by measuring voltage distribution around the joint boundary. No potential voltage gap was found at the interface of Ni/n-PbTe joint. In the case of Ni/p-Pb0.5Sn0.5Te joint, a large potential gap was found at the interface, where the intermediate layer with complicated composition was detected by EPMA. A buffer layer of p-SnTe was introduced into the Ni/p-Pb0.5Sn0.5Te joint to reduce the interface resistivity between Ni and p-Pb0.5Sn0.5Te. Low resistivity joint of metal/semiconductor was obtained by insertion of p-SnTe between Ni and p-Pb0.5Sn0.5Te.