Thermoelectric properties of Bi{sub 2}Te{sub 3}, Sb{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3} single crystals with magnetic impurities

• Published in: Journal of solid state chemistry Vol. 193
• Main Authors: Kulbachinskii, V.A., Kytin, V.G., Kudryashov, A.A., Tarasov, P.M.
• Format: Journal Article
• Language: English
• Published: United States 15.09.2012
• Subjects: ANTIMONY TELLURIDES; BISMUTH SELENIDES; BISMUTH TELLURIDES; DOPED MATERIALS; ELECTRIC CONDUCTIVITY; IMPURITIES; MATERIALS SCIENCE; MONOCRYSTALS; SHUBNIKOV-DE HAAS EFFECT; THERMOELECTRIC PROPERTIES
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/J.JSSC.2012.03.042

Temparature dependence of Seebeck coefficients S, electrical conductivity, heat conductivity k and dimensionless thermoelectric figure of merit ZT of p-Bi{sub 2}Te{sub 3}, Sb{sub 2}Te{sub 3} and n-Bi{sub 2}Se{sub 3}-doped by Fe or Cr were carried out in the temperature interval 7<T<300 K. At T=4.2 K Shubnikov-de Haas and Hall effects have been measured. By increasing the Fe content, the hole concentration decreases in p-Bi{sub 2-x}Fe{sub x}Te{sub 3}, while the electron concentration increases in n-Bi{sub 2-x}Fe{sub x}Se{sub 3}. The decrease of the hole concentration was observed in p-Sb{sub 2-x}Cr{sub x}Te{sub 3} single crystals with Cr-doping. This demonstrates that Fe or Cr act as donors. The Seebeck coefficient increases in p-Bi{sub 2-x}Fe{sub x}Te{sub 3} and Sb{sub 2-x}Cr{sub x}Te{sub 3} with increasing Fe or Cr content, while it decreases in n-Bi{sub 2-x}Fe{sub x}Se{sub 3}. Cr-doping increases dimensionless thermoelectric figure of merit ZT in Sb{sub 2}Te{sub 3} at T>150 K. - Graphical abstract: Temparature dependence of Seebeck coefficients S, electrical conductivity {sigma}, heat conductivity k and dimensionless thermoelectric figure of merit ZT of p-Bi{sub 2}Te{sub 3}, Sb{sub 2}Te{sub 3} and n-Bi{sub 2}Se{sub 3} doped by Fe or Cr were measured in the temperature interval 7<T<300 K. The Seebeck coefficient increases in p-Bi{sub 2-x}Fe{sub x}Te{sub 3} and Sb{sub 2-x}Cr{sub x}Te{sub 3} with increasing Fe or Cr content, while it decreases in n-Bi{sub 2-x}Fe{sub x}Se{sub 3}. Cr-doping increases thermoelectric figure of merit in Sb{sub 2}Te{sub 3} at T>150 K up to ZT=0.4 as shown in figure. Highlights: Black-Right-Pointing-Pointer Fe and Cr act as donors in Bi{sub 2}Te{sub 3}, Sb{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3.} Black-Right-Pointing-Pointer The Seebeck coefficient increases in p-Bi{sub 2-x}Fe{sub x}Te{sub 3} and Sb{sub 2-x}Cr{sub x}Te{sub 3}. Black-Right-Pointing-Pointer Dimensionless figure of merit ZT increased up to 0.4 in Cr-doped Sb{sub 2}Te{sub 3} at T=300 K.