Thermally stable, low resistance Mg2Si0.4Sn0.6/Cu thermoelectric contacts using SS 304 interlayer by one step sintering

Abstract Device fabrication using Mg2Si1-xSnx thermoelectric (TE) material for 600–800 K application requires stable and low resistance electrical contacts between TE legs and the electrodes. In this study, n-type Mg2Si0.4Sn0.6Bi0.02 was hot-pressed with Cu electrodes in a single step, resulting in Cu3Mg2Si and Cu4MgSn phases at the interface. Although the specific contact resistance (rc) across the interface was 4.4 ± 0.9 µΩ.cm2, the electrical resistivity of the TE leg increased by approximately 60% due to Cu diffusion through the interface. Incorporating the SS304 interlayer to prevent Cu diffusion increased rc to 6.1 ± 2 µΩ.cm2. Upon annealing at 723 K for 3–15 days, rc remained at