2022

<2> Effective terahertz shielding properties of extreme graphene-silver nanowire surfaces investigated by nanoprobing

Geon Lee,Sung Jun Kim,Yeeun Roh,Sang-Hun Lee,Dai-Sik Kim,Sang Woo Kim,Minah Seo

iScience 25, 104033 (2022)

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Abstract:In the terahertz (THz) electromagnetic wave regime, which has recently received great attention in the fields of communication and security, shielding of THz waves is a significant issue. Therefore, carbon-based nanostructures or polymer–carbon nanocomposites have been widely explored. Herein, significantly enhanced THz shielding efficiency is reported for silver nanowires coated with reduced graphene oxide (rGO) and nanoscale THz metamaterials, as compared to the cases without nanoscale metamaterials. Using a nanoslot-patterned metamaterial with strong resonances at certain frequencies, THz transmission in intensity is enhanced up to three orders of magnitude. Enhanced transmission by nanopatterns substantially increases the shielding performance to the external THz waves, even for ultrathin films (several tens of nanometers) produced by a simple spray of rGO (a few nm of flakes) on a complex random nanowire network. Excellent shielding performance is presented and the shielding mechanism is investigated by the nanoprobing configuration at the same time.

<1> Perspective on future applications with lights concentrated in zero‑nanometer gaps

Hyunwoo Kim and Dai-Sik Kim

Journal of the Korean Physical Society, 4884 (2022)

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Abstract: Nanogap metallic structures is a useful platform for efficient manipulation of the light-matter interaction in extreme subwavelength scale. With the recent advances in fabrication technology, zero-nanometer scale (angstrom) gaps are now available with unprecedented control capability in gap widths, and with scalability in area and uniformity. In this paper, we provide perspectives on potential novel applications of zero-nanometer gaps. By reviewing the current research trends in two-dimensional material based optoelectronics, and novel lithography techniques, we explore the opportunities given to the zero-nanometer gap structures. Optoelectronic devices based on two-dimensional materials will have facile tuning capabilities in carrier excitation efficiency and working wavelengths when the zero-nanometer gaps are incorporated in the devices. In photolithography, patterning resolution can be reduced down to sub-nanometer. We anticipate that the perspectives described in the paper motivate the further researches in zero-nanometer gap applications opening the era of Gaptronics.