A low-temperature, water-free fabrication route to Mg-based micro thermoelectric coolers for thermal management.

Yang, Jiawei; Zhu, Rui; Li, Ming; Mei, Zengxia; Chen, Ling; Wu, Li-Ming · Nat Commun · 2026

basic_science · Level V

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Abstract

Sustainable thermal management of high-heat-flux electronics beyond Moore's Law requires micro thermoelectric coolers (μ-TECs) that are both high-performance and environmentally sustainable. However, state-of-the-art μ-TECs rely on Bi<sub>2</sub>Te<sub>3</sub>-based materials, whose tellurium scarcity, toxicity concerns and limited mechanical robustness hinder widespread adoption. Mg-based thermoelectric materials offer a promising alternative but remain challenging to integrate into microscale devices. Here we show that a low-temperature, water-free fabrication strategy enables tellurium-minimized μ-TECs based on n-type Mg<sub>3</sub>(Bi,Sb)<sub>2</sub> and p-type MgAgSb. Using magnetron sputtering as a cold bonding approach, we fabricate compact 12-pair microdevices (2.95 × 4.35 × 1.4 mm<sup>3</sup>), with thermoelectric legs approximately 3% the size of previously reported Mg-based devices. The resulting μ-TECs achieve a power density of 4.34 W cm<sup>-2</sup> and a packing density of 93.5 pairs cm<sup>-2</sup>. Our work establishes a scalable route for sustainable thermoelectric cooling and a viable alternative to conventional Bi<sub>2</sub>Te<sub>3</sub> technologies.