Strain-engineered Allotrope-like Bismuth Nanowires for Enhanced Thermoelectric Performance

Title
Strain-engineered Allotrope-like Bismuth Nanowires for Enhanced Thermoelectric Performance
Authors
천동원배지환Jeongmin KimMin-Wook OhGwansik KimJe-Hyeong BahkJae Yong SongSeong Gi JeonWooyoung ShimWooyoung Lee
Keywords
Thermoelectric; Figure of merit; Strained nanowir; Bismuth nanowir; Band engineering
Issue Date
2018-02
Publisher
Acta materialia
Citation
VOL 144-153
Abstract
Allotropy is a fundamental concept that has been frequently studied since the mid-1800s. Although the bulk allotropy of elemental solids is fairly well understood, it remains challenging to reliably produce an allotrope at the nanoscale that has a different crystal structure and accompanies a change in physical properties for specific applications. Here, we demonstrate a "heterostructure" approach to produce allotrope-like bismuth nanowires, where it utilizes the lattice constant difference between bismuth and tellurium in core/shell structure.We find that the resultant strain of [100]-grown Bi nanowires increases the atomic linear density along the c-axis that has been predicted from theoretical considerations, enabling us to establish a design rule for strain-induced allotropic transformation. With our >400-nmdiameter nanowires, we measure a thermoelectric figure of merit ZT of 0.5 at room temperature with reduced thermal conductivity and enhanced Seebeck coefficient, which are primarily a result of the rough interface and the reduced band overlap according to our density-functional calculations.
URI
http://pubs.kist.re.kr/handle/201004/67387
ISSN
1359-6454
Appears in Collections:
KIST Publication > Article
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