High thermoelectric figure of merit of porous Si nanowires from 300 to 700 K

Lin Yang, Daihong Huh, Rui Ning, Vi Rapp, Yuqiang Zeng, Yunzhi Liu, Sucheol Ju, Yi Tao, Yue Jiang, Jihyun Beak, Juyoung Leem, Sumanjeet Kaur, Heon Lee, Xiaolin Zheng, Ravi S. Prasher

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Thermoelectrics operating at high temperature can cost-effectively convert waste heat and compete with other zero-carbon technologies. Among different high-temperature thermoelectrics materials, silicon nanowires possess the combined attributes of cost effectiveness and mature manufacturing infrastructures. Despite significant breakthroughs in silicon nanowires based thermoelectrics for waste heat conversion, the figure of merit (ZT) or operating temperature has remained low. Here, we report the synthesis of large-area, wafer-scale arrays of porous silicon nanowires with ultra-thin Si crystallite size of ~4 nm. Concurrent measurements of thermal conductivity (κ), electrical conductivity (σ), and Seebeck coefficient (S) on the same nanowire show a ZT of 0.71 at 700 K, which is more than ~18 times higher than bulk Si. This ZT value is more than two times higher than any nanostructured Si-based thermoelectrics reported in the literature at 700 K. Experimental data and theoretical modeling demonstrate that this work has the potential to achieve a ZT of ~1 at 1000 K.

Original languageEnglish
Pages (from-to)3926
Number of pages1
JournalNature communications
Volume12
Issue number1
DOIs
Publication statusPublished - 2021 Jun 24

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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