Fe-Ni-Cr diffusion barrier for high-temperature operation of Bi2Te3

Bismuth-telluride (Bi2Te3)-based thermoelectric modules are widely used in practical applications at room temperature. However, to enable the utilization of waste heat sources, Bi2Te3-based thermoelectric modules need to operate at high efficiency levels over a medium temperature range (200-250 degrees C). To achieve high efficiency of Bi2Te3 modules operating at this temperature range, an optimal metallization layer should be inserted to minimize the electrical and thermal contact resistance and prevent elemental diffusion at the interface. In this work, we suggest a novel Fe-Ni-Cr layer to overcome the poor performance of the Ni layer, which is currently widely used as a metallization layer. The proposed Fe-Ni-Cr metallization resulted in a strong enough interface structure without any detachment even after thermal aging whereas the Ni-Cr metallization suffered from layer detachment problems. The specific electrical contact resistance of Fe-Ni-Cr metallization showed minor increase and remains at the similar to 10-5 Omega middotcm2 level after thermal aging at 250 celcius for 100 h. The reliability of the Fe-Ni-Cr metallization layer was demonstrated with a 32-couples ther-moelectric module, which showed a 5 % enhancement compared to Ni metallization thermoelectric module.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Bismuth-telluride (Bi2Te3)-based thermoelectric modules require an optimal metallization layer to achieve high efficiency operation at medium temperatures. This study proposes a novel Fe-Ni-Cr layer to overcome the performance limitations of the widely used Ni layer. The Fe-Ni-Cr metallization demonstrated better performance and reliability compared to Ni metallization.