ELECTRON TRANSPORT PROPERTIES OF THERMOELECTRICS BASED ON LAYERED SUBSTITUTED TRANSITION METAL DICHALCOGENIDES
A. I. Romanenko1,2, G. E. Yakovleva1, V. E. Fedorov1,3, A. Yu. Ledneva1, V. A. Kuznetsov1, A. V. Sotnikov1, A. R. Tsygankova1,3, B. M. Kuchumov1
1Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Tomsk National Research State University, Tomsk, Russia
3Novosibirsk National Research State University, Novosibirsk, Russia
Keywords: слоистые халькогениды переходных металлов, электропроводность, термоэдс, layered transition metal chalcogenides, electrical conductivity, Seebeck coefficient
Abstract
Temperature dependences of the electrical conductivity are studied in the range 4.2-300 K and Seebeck coefficient at room temperature of bulk samples of tungsten dichalcogenide polycrystals with niobium substitutions for tungsten and selenium substitutions for sulfur - W1- x Nb x (S1- y Se y )2. The two-dimensionalization of electron transport properties is detected at niobium concentrations x ³ 0.1 in W1- x Nb x S2 and x ³ 0.05 in W1- x Nb x Se2. In samples with additional partial selenium substitution for sulfur the electron transport remains three-dimensional. At room temperature the Seebeck coefficient (at equal electrical conductivities) is several times higher in the samples with quasi-two- dimensional transport than in the samples with three-dimensional transport. The calculation of the power factor at room temperature shows its nine times increase.
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