Resonant levels (RLs) are expected to increase the density of states (DOS) abruptly, thereby increasing the Seebeck coefficient for a high thermoelectric figure of merit (ZT). However, the negative effects of RLs on reducing the carrier mobility and band gap have rarely been explored. In this work, the pros and cons of resonant‐state doping of group IIIA elements (In, Ga) in GeTe‐based alloys are studied by experimental transport properties and density‐functional‐theory calculations. RLs effects of Fermi level pinning and increased effective mass are strong in Ge0.9‐xInxSb0.1Te but weak in Ge0.9‐y(In0.5Ga0.5)ySb0.1Te, which shows dependence on the hump DOS relative to the background, location of RLs, and energy width of RLs. Using the In‐Ga co‐doping strategy to make a compromise between the DOS, carrier mobility, and bipolar transport, combined with beneficial alloying effects of Pb and Sb, a peak ZT≈ 2.1 at 773 K and a high average ZT≈ 1.43 within 300–773 K can be obtained in Ge0.78In0.005Ga0.005Pb0.1Sb0.07Te. The corresponding single‐leg device shows a remarkable energy conversion efficiency of 13.7% at a temperature difference of 451 K. This work suggests that RLs are not always beneficial for improving ZT, and the compromise design of RLs should be carefully considered to advance ZT.

中文翻译：

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具有增强热电性能的 GeTe 基合金谐振能级的折衷设计

谐振能级（RL）预计会突然增加态密度（DOS），从而增加塞贝克系数以获得高热电品质因数（ZT）。然而，RL 对降低载流子迁移率和带隙的负面影响却很少被探讨。在这项工作中，通过实验输运特性和密度泛函理论计算研究了 GeTe 基合金中 IIIA 族元素（In、Ga）谐振态掺杂的优缺点。费米能级钉扎和有效质量增加的 RL 效应在 Ge 中很强0.9-x在X锑0.1Te 但 Ge 较弱0.9年（在0.5嘎0.5）y锑0.1Te，显示了驼峰 DOS 相对于背景、RL 位置和 RL 能量宽度的依赖性。使用 In-Ga 共掺杂策略在 DOS、载流子迁移率和双极输运之间做出折衷，结合 Pb 和 Sb 的有益合金化效应，ZT773 K 时 ≈ 2.1，平均值较高ZT在 Ge 中可以在 300–773 K 内获得 ≈ 1.430.78在0.005嘎0.005铅0.1锑0.07特。相应的单腿装置在 451 K 的温差下表现出 13.7% 的显着能量转换效率。这项工作表明 RL 并不总是有利于改善ZT，并且应该仔细考虑RL的折衷设计以推进ZT。