Dresden 2026 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 20: Poster I

HL 20.65: Poster

Tuesday, March 10, 2026, 18:00–20:00, P1

Investigation of the Thermoelectric Properties of Single-Crystalline and Polycrystalline Bi1-xSbx (x =0, 0.1, 0.15) Alloys — •Fangyi Hu, Yuan Yu, and Matthias Wuttig — I. Physikalisches Institut (IA), RWTH Aachen University, 52074 Aachen, Germany

Thermoelectric (TE) materials can directly convert heat into electricity and vice versa, providing a sustainable and clean energy solution. Bi1-xSbx, a low-temperature n-type TE alloy with great potential between 20-200 K, has drawn increasing attention in cooling applications. Single crystals and polycrystals exhibit different performance and application prospects. In most cases, particularly below 200 K, single-crystal Bi-Sb shows much higher TE performance than polycrystals. However, polycrystalline Bi-Sb offers lower fabrication cost, better mechanical strength, and easier processing, making it attractive for large-scale use. This study compares the TE properties of Bi-Sb alloys in these two forms and clarifies their intrinsic relationship. Single-crystalline and polycrystalline Bi1-xSbx (x = 0, 0.1, 0.15) were prepared by Bridgman and melt-air-cooling methods, respectively. TE properties, with and without magnetic fields, were measured using Thermal Transport Option in a physical property measurement system (PPMS). Microstructures and bonding mechanisms were analyzed via atom probe tomography. By establishing the bonding-structure-property connection, we aim to reveal the origin of the performance difference between the two forms. These results provide insights into improving ZT in polycrystalline Bi-Sb alloys, which are more suitable for practical deployment.

Keywords: thermoelectric materials; thermoelectric cooling; Single crystals; polycrystals; Bi-Sb alloys