Anisotropy analysis of thermoelectric properties of Bi{sub 2}Te{sub 2.9}Se{sub 0.1} prepared by SPS method

Journal Article · Tue Jun 26 00:00:00 EDT 2012 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4731579· OSTI ID:22068986

Zybala, Rafal; Wojciechowski, Krzysztof T ^[1]

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1. Thermoelectric Research Laboratory, Department of Inorganic Chemistry, Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Av. Mickiewicza 30, 30-059, Cracow (Poland)

The n-type Bi{sub 2}Te{sub 2.9}Se{sub 0.1} materials were synthesized by the direct fusion technique. The polycrystalline samples were fabricated by the uniaxial pressing of powders in spark plasma sintering (SPS) apparatus. The materials were subjected to the heat treatment in H{sub 2}-Ar atmosphere at 470 K for 24 h. The influence of preparation conditions on the anisotropy of electrical and thermal properties was thoroughly studied for the direction perpendicular and parallel to the pressing force. The microstructure and the chemical composition of both types of samples were examined using a scanning microscope (SEM) equipped with an X-ray energy dispersion detector (EDX). The XRD method was applied for the phase analysis of materials, as well as, for determination of preferred orientation of Bi{sub 2}Te{sub 2.9}Se{sub 0.1} grains. The Seebeck coefficient distribution was studied by the scanning thermoelectric microprobe (STM). Temperature dependences of thermoelectric properties (thermal and electrical conductivities, Seebeck coefficient) were measured in the temperature from 300 K to 550 K. The statistical analysis of results has shown strong influence of pressing force direction both on structural and transport properties. The applied heat treatment of materials significantly improves their thermoelectric figure of merit. Particularly, it was found that annealing in H2-Ar atmosphere leads to enhancement of the ZT three times up to {approx}0.7 at 370 K in perpendicular direction to the pressing force.

• OSTI ID: 22068986
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1449; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
BISMUTH SELENIDES
BISMUTH TELLURIDES
CHEMICAL COMPOSITION
ELECTRIC CONDUCTIVITY
GRAIN ORIENTATION
GRAIN SIZE
MELTING
PHASE STUDIES
PLASMA
POLYCRYSTALS
SCANNING ELECTRON MICROSCOPY
SCANNING TUNNELING MICROSCOPY
SEEBECK EFFECT
SEMICONDUCTOR MATERIALS
SINTERING
TEMPERATURE DEPENDENCE
THERMAL CONDUCTIVITY
THERMOELECTRIC PROPERTIES
X-RAY DIFFRACTION