INVESTIGATION OF THE CAUSES OF DESTRUCTION OF CONTACTS IN TETRIMITE THERMOELECTRIC ELEMENTS

Polycrystalline thermoelectric elements of the n-type Bi₂ (Te_0.95Se_0.05) ₃ and p-type (Bi_0.25Sb_0.75) ₂Te₃ were fabricated using the modified Bridgman technique followed by electric spark cutting. A thermoelectric micromodule consisting of 12 thermoelements with an antidiffusion barrier Ni and a high-temperature SnSb interlayer was assembled. To study the thermocouples under conditions close to the working ones, the micromodule was annealed at 170 ° C for 1000 hours. It was found that, after annealing for more than 40 hours, disruptions of the contact zone of the n-type are observed, which leads to a complete rupture of the contacts of the micromodules. Our results showed that during annealing the SnSb takes place in the unprotected side surface of the thermoelement and contacts the cleavage planes along which the tin can diffuse into the volume of the thermoelement. In contrast, p-type pins were not destroyed by solder. The difference in the effect of the solder on the n- and p-type thermoelements was explained within the framework of the density functional theory (DFT). Calculations for substitution, diffusion, and thermodynamic stability have shown that the replacement of Bi-Sn is four times more advantageous than the substitution of Sb-Sn. In addition, it was calculated that for the Bi₂Te₃ + Sn system it is more advantageous to form TeSn and Bi-phase, and the Sb₂Te₃ + Sn system is thermodynamically stable.

1. 1 B. Poudel, Q. Hao, Y. Ma, Y. Lan, A. Minnich, B. Yu, X. Yan, D. Wang, A. Muto, D. Vashaee, X. Chen, J. Liu, M. S. Dresselhaus, G. Chen, and Z. Ren. High-thermoelectric performance of nanostructured bismuth antimony telluride bulk alloys. Science (80-. ). 320, 634 (2008).

2. M. Kashiwagi, S. Hirata, K. Harada, Y. Zheng, K. Miyazaki, M. Yahiro, and C. Adachi. Combined effect of nanoscale grain size and porosity on lattice thermal conductivity of bismuth-telluride-based bulk alloys. Appl. Phys. Lett. 98, 023114 (2011).

3. W. Xie, D. A. Hitchcock, H. J. Kang, J. He, X. Tang, M. Laver, and B. Hammouda, The microstructure network and thermoelectric properties of bulk (Bi,Sb)2Te3 Appl. Phys. Lett. 101, 113902 (2012).

4. Y. Zhang, X. Jia, L. Deng, X. Guo, H. Sun, B. Sun, B. Liu, and H. Ma. Composition controlled preparation of Cu–Zn–Sn precursor films for Cu2ZnSnS4 solar cells using pulsed electrodeposition. J. Alloys Compd. 632, 514 (2015).

5. Q. Lognoné and F. Gascoin, Reactivity, stability and thermoelectric properties of n-Bi2Te3 doped with different copper amounts. J. Alloys Compd. 635, 107 (2015).

6. L. E. Bell, Cooling, Heating, Generating Power, and Recovering Waste Heat with Thermoelectric Systems. Science (80-. ). 321, 1457 (2008).

7. K. Koumoto and T. Mori, Thermoelectric Nanomaterials: Materials Design and Applications (Springer, Heidelberg, 2013).

8. B. M. Goltsman, B. A. Kudinov, and I. A. Smirnov, Thermoelectric Semiconductor Materials Based on Bi2Te3 (Defense Technical Information Center, Ft. Belvoir, 1973).

9. V. T. Bublik, A. I. Voronin, E. A. Vygovskaya, V. F. Ponomarev, N. Y. Tabachkova, and O. V. Toropova. Structure of Profiled Crystals Based on Solid Solutions of Bi2Te3 and Their X-Ray Diagnostics. Russ. Microelectron. 40, 634 (2011).

10. W. Liu, H. Wang, L. Wang, X. Wang, G. Joshi, G. Chen, and Z. Ren. Understanding of the contact of nanostructured thermoelectric n-type Bi2Te2.7Se0.3 legs for power generation applications. J. Mater. Chem. A 1, 13093 (2013).

11. S. Chen, T. Yang, C. Wu, H. Hsiao, H. Chu, J. Huang, and T. Liou. Residual stress measurement on TiN thin films by combing nanoindentation and average X-ray strain (AXS) method. J. Alloys Compd. 686, 847 (2016).

12. V. D. Demcheglo, A. I. Voronin, N. Y. Tabachkova, V. T. Bublik, and V. F. Ponomaryov. Structure of Bi2Se0.3Te2.7 alloy plates obtained by crystallization in a flat cavity by the Bridgman method. Semiconductors 51, 1021 (2017).

13. V. T. Bublik, A. I. Voronin, E. A. Vygovskaya, V. F. Ponomarev, N. Y. Tabachkova, and O. V. Toropova. Analysis of anisotropy of properties on the basis of studies of texture of coarse-grained ingots of thermoelectric materials. Inorg. Mater. 47, 1563 (2011).

14. T. C. Harman. Special Techniques for Measurement of Thermoelectric Properties. J. Appl. Phys. 29, 1373 (1958).

15. Y. Feutelais, B. Legendre, N. Rodier, and V. Agafonov. A study of the phases in the bismuth - tellurium system. Mater. Res. Bull. 28, 591 (1993).

16. S. A. Semiletov. Kristallografiya 1, 403 (1956).

17. A. F. Ioffe. Semiconductor Thermoelements, and Thermoelectric Cooling (Infosearch, London, 1957).

18. R. W. G. Wyckoff, in Cryst. Struct. Second Ed. Arsenic and Chlorine Co-Doping to CH3NH3PbI3 Perovskite Solar Cells (Interscience Publishers, New York, 1963), pp. 85–237.

19. P. E. Blöchl, Projector augmented-wave method. Phys. Rev. B 50, 17953 (1994).

20. J. Perdew, K. Burke, and M. Ernzerhof, Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 77, 3865 (1996).

21. G. Kresse and J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169 (1996).

22. G. Kresse and D. Joubert. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758 (1999).

23. G. Henkelman, B. Uberuaga, and H. Jónsson. A climbing image nudged elastic band method for finding saddle points and minimum energy paths. J. Chem. Phys. 113, 9901 (2000).