Synergistically Optimized Thermal Conductivity and Carrier Concentration in GeTe by Bi-Se Codoping

Liang Xu; Gang Wu; Ruoyu Wang; Zipeng Yan; Jianfeng Cai; Juanxuan Yang; Xuemei Wang; Jun Luo; Xiaojian Tan; Guoqiang Liu; Jun Jiang

doi:10.1021/acsami.2c00546

Synergistically Optimized Thermal Conductivity and Carrier Concentration in GeTe by Bi-Se Codoping

ACS Appl Mater Interfaces. 2022 Mar 30;14(12):14359-14366. doi: 10.1021/acsami.2c00546. Epub 2022 Mar 17.

Authors

Liang Xu^{1

2}, Gang Wu^{2

3}, Ruoyu Wang^{2

3}, Zipeng Yan², Jianfeng Cai^{2

3}, Juanxuan Yang², Xuemei Wang^{2

3}, Jun Luo¹, Xiaojian Tan^{2

3}, Guoqiang Liu^{2

3}, Jun Jiang^{2

3}

Affiliations

¹ School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China.
² Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
³ University of Chinese Academy of Science, Beijing 100049, China.

PMID: 35297604
DOI: 10.1021/acsami.2c00546

Abstract

The GeTe compound has been revealed to be an outstanding thermoelectric compound, while its inherent high thermal conductivity restricts further improvement in its performance. Herein, we report a study on the synergistic optimization of the thermoelectric performance of GeTe by Bi-Se codoping. It is shown that the introduction of Bi decreases the carrier concentration and increases the structural parameter of the interaxial angle. With Se doping in the Te site, the lattice thermal conductivity is markedly reduced, while the carrier mobility is slightly influenced. Compared with the singly Se-doped GeTe, the Ge_1-xBi_xTe_1-ySe_y samples are more closed to a cubic phase, as indicated by the larger interaxial angle. On account of the reduction of carrier concentration and thermal conductivity, a ZT_max of 1.80 at 665 K and a high ZT_ave of 1.39 (400-800 K) are obtained in Ge_0.94Bi_0.06Te_0.85Se_0.15. This work reveals that the interaxial angle is vital to the performance optimization of rhombohedral GeTe.

Keywords: Bi−Se codoping; GeTe; carrier mobility; interaxial angle; lattice thermal conductivity.