Anisotropy of 3D Columnar Coatings in Mid-Infrared Spectral Range

Lina Grineviciute; Soon Hock Ng; Molong Han; Tania Moein; Vijayakumar Anand; Tomas Katkus; Meguya Ryu; Junko Morikawa; Mark J. Tobin; Jitraporn Vongsvivut; Tomas Tolenis; Saulius Juodkazis

doi:10.3390/nano11123247

Nanomaterials (Nov 2021)

Anisotropy of 3D Columnar Coatings in Mid-Infrared Spectral Range

Lina Grineviciute,
Soon Hock Ng,
Molong Han,
Tania Moein,
Vijayakumar Anand,
Tomas Katkus,
Meguya Ryu,
Junko Morikawa,
Mark J. Tobin,
Jitraporn Vongsvivut,
Tomas Tolenis,
Saulius Juodkazis

Affiliations

Lina Grineviciute: Center for Physical Sciences and Technology, Savanoriu̧ Ave. 231, LT-02300 Vilnius, Lithuania
Soon Hock Ng: Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
Molong Han: Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
Tania Moein: Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
Vijayakumar Anand: Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
Tomas Katkus: Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
Meguya Ryu: Research Institute for Material and Chemical Measurement, National Metrology Institute of Japan (AIST), Tsukuba Central 3, 1-1-1 Umezono, Tsukuba 305-8563, Japan
Junko Morikawa: CREST—JST and School of Materials and Chemical Technology, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
Mark J. Tobin: Infrared Microspectroscopy (IRM) Beamline, ANSTO-Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168, Australia
Jitraporn Vongsvivut: Infrared Microspectroscopy (IRM) Beamline, ANSTO-Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168, Australia
Tomas Tolenis: Center for Physical Sciences and Technology, Savanoriu̧ Ave. 231, LT-02300 Vilnius, Lithuania
Saulius Juodkazis: Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Swinburne University of Technology, Hawthorn, VIC 3122, Australia

DOI: https://doi.org/10.3390/nano11123247
Journal volume & issue: Vol. 11, no. 12
p. 3247

Abstract

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Polarisation analysis in the mid-infrared fingerprint region was carried out on thin (∼1 μm) Si and SiO2 films evaporated via glancing angle deposition (GLAD) method at 70∘ to the normal. Synchrotron-based infrared microspectroscopic measurements were carried out on the Infrared Microspectroscopy (IRM) beamline at Australian Synchrotron. Specific absorption bands, particularly Si-O-Si stretching vibration, was found to follow the angular dependence of ∼cos2θ, consistent with the absorption anisotropy. This unexpected anisotropy stems from the enhanced absorption in nano-crevices, which have orientation following the cos2θ angular dependence as revealed by Fourier transforming the image of the surface of 3D columnar films and numerical modeling of light field enhancement by sub-wavelength nano-crevices.

Published in Nanomaterials

ISSN: 2079-4991 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science: Chemistry
Website: https://www.mdpi.com/journal/nanomaterials

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