AVS 65th International Symposium & Exhibition
    Spectroscopic Ellipsometry Focus Topic Monday Sessions
       Session EL+AS+EM-MoM

Paper EL+AS+EM-MoM3
Spectroscopic Ellipsometry and Finite Element Modeling based Optical Characterization of Highly Coherent Au-Si Slanted Columnar Periodic Nanostructures

Monday, October 22, 2018, 9:00 am, Room 202A

Session: Application of SE for the Characterization of Thin Films and Nanostructures
Presenter: Ufuk Kilic, University of Nebraska-Lincoln
Authors: U. Kilic, University of Nebraska-Lincoln
A. Mock, Linkӧping University, Sweden
R. Feder, Fraunhofer IMWS, Germany
D. Sekora, University of Nebraska-Lincoln
M. Hilfiker, University of Nebraska-Lincoln
R. Korlacki, University of Nebraska-Lincoln
E. Schubert, University of Nebraska-Lincoln
C. Argyropoulos, University of Nebraska-Lincoln
M. Schubert, University of Nebraska-Lincoln
Correspondent: Click to Email
An unprecedented and phenomenal control of anisotropic optical properties of a material is reported here by utilizing periodic arrangement of nanostructures. These artificially engineered structures exhibit distinct optical, mechanical, and magnetic properties when they are compared with their bulk counterparts which has recently gained a growing interest due to its potential applications in various optical and optoelectronic systems such as lenses, solar cells, photodetectors, and sensors [1-3]. In addition to the material choices (ie. elemental composition), the size and shape of these artificial structures also play a key role in tailoring the aforementioned inherent properties.

Unraveling the mechanisms that influence and control the optical properties of highly-porous, periodic, and three-dimensional arrangements of nanoplasmonic structures can offer new approaches for the development of next generation sensors. Glancing angle deposition and atomic layer deposition can be used to create periodic nanostructures with multiple constituent materials, so-called heterostructured metamaterials.[4] In this study, we employ a two-source (ie. Au and Si) electron-beam-evaporated, ultra-high-vacuum glancing angle deposition which allows for the fabrication of highly-ordered and spatially-coherent super-lattice type Au-Si slanted columnar heterostructured thin films. We perform a combinatorial spectroscopic generalized ellipsometry and finite-element method calculation analysis to determine anisotropic optical properties. We observe the occurrence of a strong locally enhanced dark quadrupole plasmonic resonance mode (bow-tie mode) in the vicinity of the gold junctions, with a tunable and geometry dependent frequency in the near-infrared spectral range. In addition, inter-band transition-like modes are observed in the visible to ultra-violet spectral regions. We demonstrate that changes in the index of refraction due to the concentration variation of a chemical substance environment (gaseous or liquid) within a porous nanoplasmonic structure can be detected by transmitted intensity alterations down to 1 ppm sensitivity.

References

[1] Kabashin, A. V., et al. Nature materials 8.11 (2009): 867.

[2] Schmidt, Daniel, and Mathias Schubert. Journal of Applied Physics 114.8 (2013): 083510.

[3] Frölich, Andreas, and Martin Wegener. Optical Materials Express 1.5 (2011): 883-889.

[4] Sekora, Derek, et al. Applied Surface Science 421 (2017): 783-787.