| dc.description.abstract | Because of the increasing demand for alternative sources of energy, the development of medium-temperature thermoelectric modules has gained much attention in recent decades. Lead telluride (PbTe) alloy is known for its high thermoelectric performance in both n-type and p-type compounds at temperatures ranging from 200–600 C; however, the performance and stability of the thermoelectric modules during applications are critical concerns in developing practical products. Severe reactions between PbTe alloy, the electrode, and the joining interlayers greatly affect the efficiency of thermoelectric modules. This study investigated the interfacial stability, electrical contact, and mechanical reliability for both n- and p-types PbTe materials on Cu and Ni electrodes with and without Co–P diffusion barrier layer, considering utilization in microelectronics packaging. Severe reactions occurred between medium-temperature thermoelectric PbTe alloys and the Cu or Ni electrodes when they were in contact. When a Cu electrode was used, a eutectic reaction resulted in the formation of molten PbTe and large Cu2Te phases, leading to failure of the Cu/n-PbTe module, and massive Cu3Sn formation caused Cu foil depletion in Cu/p-Pb0.6Sn0.4Te module. When a Ni electrode was used, Pb and Te penetrated into the electrode, and thick needle-like Ni3-xSnTe2 phases formed in n- and p-types PbTe modules, respectively. The severe interfacial problems were avoided by utilizing a Co–P diffusion layer. The mechanical strength was improved because of the insertion of Co–P layer in PbTe joints, and acceptable electrical contacts were measured. In addition, the influence of the added layers on Seebeck coefficient and resistivity enhanced the performance and thermal stability of the tested n- and p-types PbTe thermoelectric materials within the entire temperature range. These results provide new insights for developing highly efficient and reliable n- and p-PbTe thermoelectric power-generation devices using Ni or Cu electrodes suitable for working temperatures. | en_US |