MANA International Symposium 2026

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Poster NM-20

Characterization of functional materials with nano-FTIR

Ilario Bisignano

Author

Ilario Bisignano

Affiliation

Optical Nanostructure Team, MANA, NIMS

URL

https://www.nims.go.jp/mana/jp/research/nanomaterials/optical-nanostructure.html

Biography

Dr. Ilario Bisignano completed his doctoral studies in 2026 through the University of Tsukuba and NIMS joint program, conducting his research within MANA's Optical Nanostructure Team. His PhD work focused on the infrared nanoscale spectroscopy and imaging of nitride semiconductors. Prior to his doctoral research, he earned his Master's degree in materials science from the University of Calabria, Italy, which was enriched by a six-month Erasmus traineeship at the Military University of Technology in Poland. Dr. Bisignano specializes in nanophotonics, bringing strong technical expertise in nano-FTIR and standard FTIR spectroscopy, as well as high-resolution CMOS-based thermal mapping.

Abstract

Infrared near-field spectroscopy, or nano-FTIR, provides nanoscale resolution in three dimensions to non-destructively probe the local physical and optical properties of materials1. By integrating scattering-type scanning near-field optical microscopy (s-SNOM) with Fourier-transform infrared (FTIR) detection, a broadband IR beam is focused onto the apex of a sharp probe tip, generating a highly localized and enhanced near-field interaction with the sample. Extracting both the spectroscopic amplitude and phase of the backscattered radiation enables direct mapping of the local complex dielectric function2.

Owing to its high sensitivity to subtle permittivity variations, nano-FTIR serves as a versatile platform for static material characterization and diagnostics. For instance, it allows direct visualization of the spatial carrier distribution within the two-dimensional electron gas (2DEG) of AlGaN/GaN heterostructures3 as shown in Figure 1, as well as the identification of elusive intermediate states in three-state reconfigurable binary chalcogenides4 Sb2S3 as shown in Figure 2.

Cross-sectional sample schematic and nano-FTIR hyperspectral images of AlGaN
Figure 1 (a) Schematic of the cross-sectional sample with a representation of the detection method. Hyperspectral imaging of the integrated (b) O2A and (c) O2P of the 45 nm thick AlGaN sample for the range between 700 and 737 cm-1. Simulated hyperspectral images of (d) and (e) O2P Reproduced from Bisignano et al.3 Copyright © 2025 by the authors. Licensed under CC BY 4.0.
CW-laser crystallization and nano-FTIR spectra and mapping of Sb2S3
Figure 2 (a) Schematic of CW-laser-induced heating process with Gaussian beam irradiated on the device. (b) Point-scan nano-FTIR second-order amplitude spectra of the three different states: fully quenched (FQ), intermediate-crystalline (IC) and laser-induced crystalline (LC). (c) Nano-FTIR mapping with an infrared broadband laser (500-1500 cm-1)for the Sb2S3 sample showing third-order amplitude (O3A). Adapted from Ye et al.4 Licensed under CC BY 4.0.

References

  1. Mester, L., Govyadinov, A. A., & Hillenbrand, R., Nanophotonics, 11(2), 377-390 (2022) https://doi.org/10.1515/nanoph-2021-0565
  2. Govyadinov, A. A., Mastel, S., Golmar, F., Chuvilin, A., Carney, P. S., & Hillenbrand, R., Acs Nano, 8(7), 6911-6921 (2014) https://doi.org/10.1021/nn5016314
  3. Bisignano, I., Imura, M., Tanjaya, N.K., Ye, M-J., Okada, N., Ishii, S., ACS Appl. Mater. Interfaces 17 (35), 50077–50084 (2025) https://doi.org/10.1021/acsami.5c12417
  4. Ye, M-J., Bisignano, I., Wong, R. Y-M., Chen, H-W., Takeda, Y., Chen, K-P., Ishii, S., Applied Surface Science Advances, 34, 101000 (2026) https://doi.org/10.1016/j.apsadv.2026.101000
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