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Tellurium-evaporation-annealing for p-type bismuth-antimony-telluride thermoelectric materials

Title
Tellurium-evaporation-annealing for p-type bismuth-antimony-telluride thermoelectric materials
Authors
Kim, DH[Kim, Dong Hwan]Kwon, IH[Kwon, In Hye]Kim, C[Kim, Cham]Han, B[Han, Byungchan]Im, HJ[Im, Hee-Joong]Kim, H[Kim, Hoyoung]
DGIST Authors
Kim, DH[Kim, Dong Hwan]; Kwon, IH[Kwon, In Hye]; Kim, C[Kim, Cham]; Han, B[Han, Byungchan]; Kim, H[Kim, Hoyoung]
Issue Date
2013-01-25
Citation
Journal of Alloys and Compounds, 548, 126-132
Type
Article
Article Type
Article
Keywords
Ab Initio Density Functional Theories (DFT)AnnealingAnnealing MethodsAnti-Site DefectAntimony CompoundsBismuthBismuth Antimony TellurideBismuth CompoundsBulk AlloysCalculationsCarrier ConcentrationChemical CompositionsDensity Functional TheoryEvaporationExperimental MeasurementsFigure of MeritsNano ScaleP-TypePhase TransitionsSinteringTelluriumTellurium CompoundsThermo-ElectricThermo-Electric MaterialThermo-Electric PerformanceThermo-ElectricityUnderlying Mechanism
ISSN
0925-8388
Abstract
A tellurium evaporation annealing method has been investigated to control the carrier concentration of sintered (Bi,Sb)2Te3 compounds. Hot-pressed (Bi,Sb)2Te3 bulk alloys and tellurium powders located in an evacuated ampoule, were heated to 673 K and held for 3, 12 and 48 h. The crystal structure and chemical composition in the annealed specimens were preserved, while the carrier concentrations were varied between 1.53 × 1019 and 2.57 × 1019 cm -3, and the thermal conductivity at 300 K ranged between 1.20 and 1.25 W m-1 K-1. The figure of merit at 300 K was enhanced from 0.86 to 1.06 when the specimens were annealed for 3 h. To identify the underlying mechanism, we utilized ab initio density functional theory calculations. These computations indicated that a Te ad-layer on top of the Bi2Te3 energetically favors bulk Bi atoms to migrate to the surface. Our experimental measurements and the first-principles validations consistently indicate that the tellurium evaporation annealing method is a novel process for enhancing the thermoelectric performance of Bi-Te compounds by controlling their carrier concentrations, which is particularly useful in dealing with nano-scale composites. © 2012 Elsevier B.V. All rights reserved.
URI
http://hdl.handle.net/20.500.11750/2440
DOI
10.1016/j.jallcom.2012.08.130
Publisher
Elsevier
Files:
There are no files associated with this item.
Collection:
Division of Nano∙Energy Convergence Research1. Journal Articles
Energy Systems EngineeringETC1. Journal Articles


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