Strain-engineered allotrope-like bismuth nanowires for enhanced thermoelectric performance

Jeongmin Kim, Min Wook Oh, Gwansik Kim, Je Hyeong Bahk, Jae Yong Song, Seong Gi Jeon, Dong Won Chun, Jee Hwan Bae, Wooyoung Shim, Wooyoung Lee

Research output: Contribution to journalArticle

2 Citations (Scopus)

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-nm-diameter 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.

Original languageEnglish
Pages (from-to)145-153
Number of pages9
JournalActa Materialia
Volume144
DOIs
Publication statusPublished - 2018 Feb 1

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

Cite this

Kim, J., Oh, M. W., Kim, G., Bahk, J. H., Song, J. Y., Jeon, S. G., Chun, D. W., Bae, J. H., Shim, W., & Lee, W. (2018). Strain-engineered allotrope-like bismuth nanowires for enhanced thermoelectric performance. Acta Materialia, 144, 145-153. https://doi.org/10.1016/j.actamat.2017.10.062