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Title: High thermoelectric potential of Bi{sub 2}Te{sub 3} alloyed GeTe-rich phases

Abstract

In an attempt to reduce our reliance on fossil fuels, associated with severe environmental effects, the current research is focused on the identification of the thermoelectric potential of p-type (GeTe){sub 1−x}(Bi{sub 2}Te{sub 3}){sub x} alloys, with x values of up to 20%. Higher solubility limit of Bi{sub 2}Te{sub 3} in GeTe, than previously reported, was identified around ∼9%, extending the doping potential of GeTe by the Bi{sub 2}Te{sub 3} donor dopant, for an effective compensation of the high inherent hole concentration of GeTe toward thermoelectrically optimal values. Around the solubility limit of 9%, an electronic optimization resulted in an impressive maximal thermoelectric figure of merit, ZT, of ∼1.55 at ∼410 °C, which is one of the highest ever reported for any p-type GeTe-rich alloys. Beyond the solubility limit, a Fermi Level Pinning effect of stabilizing the Seebeck coefficient was observed in the x = 12%–17% range, leading to stabilization of the maximal ZTs over an extended temperature range; an effect that was associated with the potential of the governed highly symmetric Ge{sub 8}Bi{sub 2}Te{sub 11} and Ge{sub 4}Bi{sub 2}Te{sub 7} phases to create high valence band degeneracy with several bands and multiple hole pockets on the Fermi surface. At this compositional range, co-dopingmore » with additional dopants, creating shallow impurity levels (in contrast to the deep lying level created by Bi{sub 2}Te{sub 3}), was suggested for further electronic optimization of the thermoelectric properties.« less

Authors:
; ; ;  [1]
  1. Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel)
Publication Date:
OSTI Identifier:
22597826
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 120; Journal Issue: 3; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BISMUTH TELLURIDES; CONCENTRATION RATIO; DOPED MATERIALS; FERMI LEVEL; GERMANIUM ALLOYS; GERMANIUM TELLURIDES; HOLES; OPTIMIZATION; SOLUBILITY; TELLURIUM ALLOYS; TEMPERATURE RANGE; THERMOELECTRIC PROPERTIES

Citation Formats

Madar, Naor, Givon, Tom, Mogilyansky, Dmitry, and Gelbstein, Yaniv. High thermoelectric potential of Bi{sub 2}Te{sub 3} alloyed GeTe-rich phases. United States: N. p., 2016. Web. doi:10.1063/1.4958973.
Madar, Naor, Givon, Tom, Mogilyansky, Dmitry, & Gelbstein, Yaniv. High thermoelectric potential of Bi{sub 2}Te{sub 3} alloyed GeTe-rich phases. United States. doi:10.1063/1.4958973.
Madar, Naor, Givon, Tom, Mogilyansky, Dmitry, and Gelbstein, Yaniv. Thu . "High thermoelectric potential of Bi{sub 2}Te{sub 3} alloyed GeTe-rich phases". United States. doi:10.1063/1.4958973.
@article{osti_22597826,
title = {High thermoelectric potential of Bi{sub 2}Te{sub 3} alloyed GeTe-rich phases},
author = {Madar, Naor and Givon, Tom and Mogilyansky, Dmitry and Gelbstein, Yaniv},
abstractNote = {In an attempt to reduce our reliance on fossil fuels, associated with severe environmental effects, the current research is focused on the identification of the thermoelectric potential of p-type (GeTe){sub 1−x}(Bi{sub 2}Te{sub 3}){sub x} alloys, with x values of up to 20%. Higher solubility limit of Bi{sub 2}Te{sub 3} in GeTe, than previously reported, was identified around ∼9%, extending the doping potential of GeTe by the Bi{sub 2}Te{sub 3} donor dopant, for an effective compensation of the high inherent hole concentration of GeTe toward thermoelectrically optimal values. Around the solubility limit of 9%, an electronic optimization resulted in an impressive maximal thermoelectric figure of merit, ZT, of ∼1.55 at ∼410 °C, which is one of the highest ever reported for any p-type GeTe-rich alloys. Beyond the solubility limit, a Fermi Level Pinning effect of stabilizing the Seebeck coefficient was observed in the x = 12%–17% range, leading to stabilization of the maximal ZTs over an extended temperature range; an effect that was associated with the potential of the governed highly symmetric Ge{sub 8}Bi{sub 2}Te{sub 11} and Ge{sub 4}Bi{sub 2}Te{sub 7} phases to create high valence band degeneracy with several bands and multiple hole pockets on the Fermi surface. At this compositional range, co-doping with additional dopants, creating shallow impurity levels (in contrast to the deep lying level created by Bi{sub 2}Te{sub 3}), was suggested for further electronic optimization of the thermoelectric properties.},
doi = {10.1063/1.4958973},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 3,
volume = 120,
place = {United States},
year = {2016},
month = {7}
}