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<p>GeTe, as a p-type narrow band semiconductor with a special multi-energy band structure and excellent electrical properties, is regarded as one of the most promising thermoelectric materials in the mid-temperature region. However, a high p-type carrier concentration coupled with high lattice thermal conductivity limits its TE performance. In this work, GeTe with uniform composition and stable properties is prepared by high-energy ball milling combined with hot press sintering. The electrical and thermal transport properties of GeTe were optimized by Yb doping. The results show that the introduction of the rare-earth element Yb into pristine GeTe cannot reduce its carrier concentration, but can substantially increase its density of states effective mass(<i>m*</i>), resulting in higher Seebeck coefficients (<i>S</i>) of Ge<sub>1−<i>x</i></sub>Yb<sub><i>x</i></sub>Te (<i>x</i> = 0,0.01–0.04) samples than those of pristine GeTe. Yb doping in GeTe boosts the Seebeck coefficient by facilitating the valence band convergence. Importantly, a very flat band appeared near the Fermi level. Meanwhile, the deterioration of the electrical conductivity by the Yb doping is not obvious at high temperatures. This allows Ge<sub>1−<i>x</i></sub>Yb<sub><i>x</i></sub>Te (<i>x</i> = 0,0.01 ~ 0.04) to have a higher power factor. The heavier Yb also increases the disorder in the atomic arrangement of GeTe, increasing the point defects inside the material and thus decreasing the thermal conductivity of the material. The co-optimization of the electrical and thermal transport properties allows the Ge<sub>0.98</sub>Yb<sub>0.02</sub>Te sample to achieve a peak ZT of about 1.74 at 800&#xa0;K.</p>

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Effective enhancement of thermoelectric performance of germanium telluride via Ytterbium doping

  • 期刊论文

  • 发表日期：

    2026年5月24日

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  • Youpeng Sui,
  • Jungang Chang,
  • Haorui Du,
  • Yuan Tang,
  • Pei Gao,
  • Xiaobo Lei,
  • Fanggong Cai,
  • Qinyong Zhang

摘要

GeTe, as a p-type narrow band semiconductor with a special multi-energy band structure and excellent electrical properties, is regarded as one of the most promising thermoelectric materials in the mid-temperature region. However, a high p-type carrier concentration coupled with high lattice thermal conductivity limits its TE performance. In this work, GeTe with uniform composition and stable properties is prepared by high-energy ball milling combined with hot press sintering. The electrical and thermal transport properties of GeTe were optimized by Yb doping. The results show that the introduction of the rare-earth element Yb into pristine GeTe cannot reduce its carrier concentration, but can substantially increase its density of states effective mass(m*), resulting in higher Seebeck coefficients (S) of Ge1−xYbxTe (x = 0,0.01–0.04) samples than those of pristine GeTe. Yb doping in GeTe boosts the Seebeck coefficient by facilitating the valence band convergence. Importantly, a very flat band appeared near the Fermi level. Meanwhile, the deterioration of the electrical conductivity by the Yb doping is not obvious at high temperatures. This allows Ge1−xYbxTe (x = 0,0.01 ~ 0.04) to have a higher power factor. The heavier Yb also increases the disorder in the atomic arrangement of GeTe, increasing the point defects inside the material and thus decreasing the thermal conductivity of the material. The co-optimization of the electrical and thermal transport properties allows the Ge0.98Yb0.02Te sample to achieve a peak ZT of about 1.74 at 800 K.