Low contact resistivity and excellent thermal stability of p‐type YbMg_0.8Zn_1.2Sb₂/Fe‐Sb junction for thermoelectric applications

1-2-2 Zintl phase compound is a promising thermoelectric material and holds potential for thermoelectric applications. Currently, there are many reports on Zintl-phase thermoelectric materials with high zT values. However, studies on the contact materials for the Zintl phase compounds have seldom been reported. Herein, an ohmic contact is realized in the YbMg_0.8Zn_1.2Sb₂/Fe junction with a contact resistivity of less than 1 μΩ cm². The microstructural analysis shows that the interface reaction layer is composed of a Fe-Sb alloy layer and a Sb-poor Zintl layer. After 400 h of annealing at 773 K, the contact resistivity increased to ∼5.69 μΩ cm² due to the increased thickness of the Sb-poor layer and the decreased Sb content in the Sb-poor layer. To suppress the diffusion of the Sb element, the Fe-Sb layer with the nominal composition of Fe₉₀Sb₁₀ is chosen as the contact material. Our results show that the junction of YbMg_0.8Zn_1.2Sb₂/Fe-Sb exhibits an extremely low contact resistivity, an excellent thermal stability, and good mechanical properties.