Electronic properties of semiconductors

Thermoelectric properties of Ag$_8$Ge$_{1-x}$Mn$_x$Te$_6$ solid solutions

R. N. Ragimov^a, A. S. Qahramanova^a, D. G. Arasly^a, A. A. Khalilova^a, I. Kh. Mammadov^b, A. R. Khalilzade<sup>c

a</sup> Institute of Physics Azerbaijan Academy of Sciences, AZ1143 Baku, Azerbaijan
^b Azerbaijan State Aviation Academy, AZ1045 Baku, Bina, Azerbaijan
^c University of Waterloo, 200 University Ave W, Waterloo, ON N2L 3G1, Canada

Abstract: Ag$_8$Ge$_{1-x}$Mn$_x$Te$_6$ solid solutions with different manganese content ($x$ = 0, 0.05, 0.1, 0.2) were prepared by alloying and further pressing the powders under a pressure of 0.6 GPa. By the X-ray diffraction studies have shown that the introduction of manganese atoms leads to the compressibility of the Ag$_8$GeTe$_6$ lattice. All p-type samples had high resistance below the transition at temperatures of 180–220 K. An increase in electrical conductivity in the range of 220–300 K was analyzed using the Mott ratio; at temperatures $T >$ 320 K, semiconductor behavior is observed in all compositions. The highest thermoelectric figure of merit $ZT$ = 0.7 at 550 K was obtained for a solid solution of the composition Ag$_8$Ge$_{1-x}$Mn$_x$Te$_6$ ($x$ = 0.05).

Keywords: solid solution, Ag$_8$Ge$_{1-x}$Mn$_x$Te$_6$, thermoelectric efficiency, amorphization, low thermal conductivity.

Received: 18.11.2021
Revised: 18.01.2022
Accepted: 10.06.2022

DOI: 10.21883/FTP.2022.09.53406.9760

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