Miniaturized planar Si-nanowire micro-thermoelectric generator using exuded thermal field for power generation

Tianzhuo Zhan, Ryo Yamato, Shuichiro Hashimoto, Motohiro Tomita, Shunsuke Oba, Yuya Himeda, Kohei Mesaki, Hiroki Takezawa, Ryo Yokogawa, Yibin Xu, Takashi Matsukawa, Atsushi Ogura, Yoshinari Kamakura, Takanobu Watanabe

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

For harvesting energy from waste heat, the power generation densities and fabrication costs of thermoelectric generators (TEGs) are considered more important than their conversion efficiency because waste heat energy is essentially obtained free of charge. In this study, we propose a miniaturized planar Si-nanowire micro-thermoelectric generator (SiNW-μTEG) architecture, which could be simply fabricated using the complementary metal–oxide–semiconductor–compatible process. Compared with the conventional nanowire μTEGs, this SiNW-μTEG features the use of an exuded thermal field for power generation. Thus, there is no need to etch away the substrate to form suspended SiNWs, which leads to a low fabrication cost and well-protected SiNWs. We experimentally demonstrate that the power generation density of the SiNW-μTEGs was enhanced by four orders of magnitude when the SiNWs were shortened from 280 to 8 μm. Furthermore, we reduced the parasitic thermal resistance, which becomes significant in the shortened SiNW-μTEGs, by optimizing the fabrication process of AlN films as a thermally conductive layer. As a result, the power generation density of the SiNW-μTEGs was enhanced by an order of magnitude for reactive sputtering as compared to non-reactive sputtering process. A power density of 27.9 nW/cm2 has been achieved. By measuring the thermal conductivities of the two AlN films, we found that the reduction in the parasitic thermal resistance was caused by an increase in the thermal conductivity of the AlN film and a decrease in the thermal boundary resistance.

Original languageEnglish
Pages (from-to)443-453
Number of pages11
JournalScience and Technology of Advanced Materials
Volume19
Issue number1
DOIs
Publication statusPublished - 2018 Dec 31

Keywords

  • Energy harvesting
  • Si-nanowire
  • exuded thermal field
  • parasitic thermal resistance
  • thermoelectric generator

ASJC Scopus subject areas

  • Materials Science(all)

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  • Cite this

    Zhan, T., Yamato, R., Hashimoto, S., Tomita, M., Oba, S., Himeda, Y., Mesaki, K., Takezawa, H., Yokogawa, R., Xu, Y., Matsukawa, T., Ogura, A., Kamakura, Y., & Watanabe, T. (2018). Miniaturized planar Si-nanowire micro-thermoelectric generator using exuded thermal field for power generation. Science and Technology of Advanced Materials, 19(1), 443-453. https://doi.org/10.1080/14686996.2018.1460177