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Thermal and Optical Properties of Porous Nanomesh Structures for Sensitive Terahertz Bolometric Detection

1
Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi 184-8588, Japan
2
National Institute of Information and Communications Technology, 4-2-1 Nukui-Kitamachi, Koganei-shi 184-8795, Japan
3
Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku 153-8505, Japan
4
Institute for Nano Quantum Information Electronics, University of Tokyo, 4-6-1 Komaba, Meguro-ku 153-8505, Japan
*
Author to whom correspondence should be addressed.
Academic Editor: Ivan Medvedev
Sensors 2022, 22(14), 5109; https://doi.org/10.3390/s22145109
Received: 30 May 2022 / Revised: 22 June 2022 / Accepted: 6 July 2022 / Published: 7 July 2022
(This article belongs to the Special Issue Sensing with Infrared and Terahertz Technologies)
Terahertz (THz) electromagnetic waves are attractive for use in nondestructive and biocompatible sensing applications. Thermal sensors are widely used for THz detection owing to the small photon energies of THz radiation, where this requires materials with low thermal conductivity and a small heat capacity to ensure the sensitive and fast operation of the sensors. In this study, we investigated the thermal and optical properties of porous nanomesh structures for sensitive THz bolometric detection. Nanometer (nm)-scale hole array structures were formed on gallium arsenide (GaAs) microelectromechanical system (MEMS) beams to improve their thermal properties. The thermal conductance of the porous MEMS beams was obtained by measuring their thermal bandwidths; it was found to decrease by as much as ~90% when the porosity (P) of the porous nanostructure was increased to ~0.69. We also measured the THz absorptance of the porous hole array structure. The results show that although the porous nanostructure has a much smaller area than the bulk material, it maintained a high coefficient of THz absorptance because the featured size was much smaller than the THz wavelength. The measured absorptance agreed well with that calculated by using the Drude model. These results demonstrate that the porous nanomesh structure is promising for developing highly sensitive THz thermal sensors. View Full-Text
Keywords: porous nanostructure; thermal conductance; terahertz sensing; terahertz absorptance; MEMS resonator; bolometer porous nanostructure; thermal conductance; terahertz sensing; terahertz absorptance; MEMS resonator; bolometer
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MDPI and ACS Style

Yamamoto, R.; Kojima, A.; Koshida, N.; Morohashi, I.; Hirakawa, K.; Zhang, Y. Thermal and Optical Properties of Porous Nanomesh Structures for Sensitive Terahertz Bolometric Detection. Sensors 2022, 22, 5109. https://doi.org/10.3390/s22145109

AMA Style

Yamamoto R, Kojima A, Koshida N, Morohashi I, Hirakawa K, Zhang Y. Thermal and Optical Properties of Porous Nanomesh Structures for Sensitive Terahertz Bolometric Detection. Sensors. 2022; 22(14):5109. https://doi.org/10.3390/s22145109

Chicago/Turabian Style

Yamamoto, Ryoko, Akira Kojima, Nobuyoshi Koshida, Isao Morohashi, Kazuhiko Hirakawa, and Ya Zhang. 2022. "Thermal and Optical Properties of Porous Nanomesh Structures for Sensitive Terahertz Bolometric Detection" Sensors 22, no. 14: 5109. https://doi.org/10.3390/s22145109

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