Ni/n-PbTe and Ni/p-Pb0.5Sn0.5Te joining by plasma activated sintering

In order to prepare the thermoelectric element, Ni electrodes were joined with n-PbTe or p-Pb_0.5Sn_0.5Te by plasma activated sintering (PAS). To reduce the interface resistivity between Ni and p-Pb_0.5Sn_0.5Te, a buffer layer of p-SnTe was introduced into the Ni/p-Pb_0.5Sn_0.5Te joint. The characterization of the Ni/n-PbTe and Ni/p-SnTe/p-Pb_0.5Sn _0.5Te junctions was carried out by measuring voltage distribution around the joint boundary. For Ni/n-PbTe joint, no potential voltage gap was found at the interface between Ni and n-PbTe. In the case of Ni/p-Pb_0.5Sn_0.5Te joint, large potential gap was found at the interface, where the intermediate layer with complicated composition was formed. With insertion of p-SnTe between Ni and p-Pb_0.5Sn_0.5Te, low resistivity joint of metal/semiconductor was formed. These results indicate that the thermoelectric elements were successfully formed by the PAS process