Journal article

Publication year: 2021

Journal: Materials

Volume number: 14

Issue number: 22

eISSN: 1996-1944

Open access status: Gold

DOI Link: https://doi.org/10.3390/ma14226774

Publisher: MDPI

Abstract: 
Thermoelectric generators are a reliable and environmentally friendly source of electrical energy. A crucial step for their development is the maximization of their efficiency. The efficiency of a TEG is inversely related to its electrical contact resistance, which it is therefore essential to minimize. In this paper, we investigate the contacting of an Al electrode on Mg-2(Si,Sn) thermoelectric material and find that samples can show highly asymmetric electrical contact resistivities on both sides of a leg (e.g., 10 mu & OHM;& BULL;cm(2) and 200 mu & OHM;& BULL;cm(2)). Differential contacting experiments allow one to identify the oxide layer on the Al foil as well as the dicing of the pellets into legs are identified as the main origins of this behavior. In order to avoid any oxidation of the foil, a thin layer of Zn is sputtered after etching the Al surface; this method proves itself effective in keeping the contact resistivities of both interfaces equally low (< 10 mu & OHM;& BULL;cm(2)) after dicing. A slight gradient is observed in the n-type leg's Seebeck coefficient after the contacting with the Zn-coated electrode and the role of Zn in this change is confirmed by comparing the experimental results to hybrid-density functional calculations of Zn point defects.

Harvard Citation style: Camut, J., Ayachi, S., Castillo-Hernandez, G., Park, S., Ryu, B., Park, S., et al. (2021) Overcoming Asymmetric Contact Resistances in Al-Contacted Mg₂(Si,Sn) Thermoelectric Legs, Materials, 14(22), Article 6774. https://doi.org/10.3390/ma14226774

APA Citation style: Camut, J., Ayachi, S., Castillo-Hernandez, G., Park, S., Ryu, B., Park, S., Frank, A., Stiewe, C., Mueller, E., & de Boor, J. (2021). Overcoming Asymmetric Contact Resistances in Al-Contacted Mg₂(Si,Sn) Thermoelectric Legs. Materials. 14(22), Article 6774. https://doi.org/10.3390/ma14226774