Broadband resonances in indium-tin-oxide nanorod arrays
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Dr., Evanston, Illinois 60208-3108 (United States)
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)
- NU-NIMS Materials Innovation Center, 2220 Campus Dr., Evanston, Illinois 60208-3108 (United States)
There is currently much discussion within the nanophotonics community regarding the origin of wavelength selective absorption/scattering of light by the resonances in nanorod arrays. Here, we report a study of resonances in ordered indium-tin-oxide nanorod arrays resulting from waveguide-like modes. We find that with only a 2.4% geometrical coverage, micron-length nanorod arrays interact strongly with light across a surprisingly wide band from the visible to the mid-infrared, resulting in less than 10% transmission. Simulations show excellent agreement with our experimental observations. The field profile in the vicinity of the rods obtained from simulations shows that the electric field is mainly localized on the surfaces of the nanorods for all resonances. Based on our analysis, the resonances in the visible are different in character from those in the infrared. When light is incident on the array, part of it propagates in the space between the rods and part of it is guided within the rods. The phase difference (interference) at the ends of the rods forms the basis for the resonances in the visible region. The resonances in the infrared are Fabry-Perot-like resonances involving standing surface waves between the opposing ends of the rods. Simple analytical formulae predict the spectral positions of these resonances. It is suggested that these phenomena can be utilized for wavelength-selective photodetectors, modulators, and nanorod-based solar cells.
- OSTI ID:
- 22486322
- Journal Information:
- Applied Physics Letters, Vol. 107, Issue 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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