デュアル欠陥工学戦略によりN型熱電薄膜の性能を向上（Dual-Defect Engineering Strategy Boosts N-Type Thermoelectric Thin Film Performance）

2026-03-02 中国科学院（CAS）

Schematic illustration of the fabrication process for n-type Mg₃(Sb, Bi)₂ thin films and the mechanism of p-type to n-type transition. (Image by IMR)

＜関連情報＞

• https://english.cas.cn/newsroom/research-news/202603/t20260302_1151351.shtml
• https://www.sciencedirect.com/science/article/abs/pii/S1359645426001187

二重欠陥工学によりn型Mg3Bi1.5Sb0.5薄膜の熱電性能を向上 Dual-defect engineering enables enhanced thermoelectric performance in n-type Mg3Bi1.5Sb0.5 thin films

Yijun Ran, Wenxue Ma, Wenxia Li, Shengqian Li, Xiaoyang Wang, Ting Xiong, Dayi Zhou, Xiangshan Kong, Ning Gao, Zhi Yu, Kaiping Tai
Acta Materialia  Available online: 11 February 2026
DOI:https://doi.org/10.1016/j.actamat.2026.122012

Abstract

Mg₃(Sb, Bi)₂-based thin films have garnered significant attention from researchers due to their promising thermoelectric properties and low raw material costs. However, Mg evaporation during high temperature deposition impedes the optimization of carrier concentration, limiting further thermoelectric performance elevation. Here, we demonstrate a breakthrough in thermoelectric performance of n-type Mg_3.15Bi_1.46Sb_0.5Te_0.04 thin films through dual-defect engineering, synergistically controlling Mg vacancy and introducing Te dopants. Regulating the Mg-rich deposition atmosphere effectively suppresses Mg vacancy formation to enable efficient n-type doping. Concurrently, Te doping optimizes carrier concentration and induces heterogeneous lattice stress that suppresses thermal conductivity by enhancing phonon scattering. As a result, a peak _ZT of 0.47 is obtained for the n-type Mg_3.15Bi_1.46Sb_0.5Te_0.04 thin film at 525 K, which ranks as the top of the Mg-based thin film materials. Integrating these optimized films into all-Mg₃(Sb, Bi)₂ devices (3-pair π-type structure) yields an output voltage (V) of ∼ 79 mV and power density (ω) of ∼ 1185 μW cm^-2 at a temperature difference (ΔT) of 120 K. This work establishes dual-defect engineering strategy as a universal design principle for thin-film thermoelectric materials, bridging the critical performance gap between bulk and film systems for mid-temperature (400–600 K) waste heat energy harvesting applications.