Screening effects in metal sculptured thin films studied with terahertz Mueller matrix ellipsometry

T. Hofmann; S. Knight; D. Sekora; D. Schmidt; C. M. Herzinger; J. A. Woollam; E. Schubert; M. Schubert

doi:10.1016/j.apsusc.2016.12.200

Screening effects in metal sculptured thin films studied with terahertz Mueller matrix ellipsometry

T. Hofmann, S. Knight, D. Sekora, D. Schmidt, C. M. Herzinger, J. A. Woollam, E. Schubert, M. Schubert

Electrical & Computer Engineering

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

The anisotropic optical dielectric functions of a metal (cobalt) slanted columnar thin film deposited by electron-beam glancing angle deposition are reported for the terahertz (THz) frequency domain before and after the slanted columnar thin film was passivated by a conformal alumina coating. A simple effective medium dielectric function homogenization approach which describes isolated, electrically conductive columns rendering the thin film biaxial (orthorhombic) is used to model the observed optical responses. Upon passivating the slanted columnar thin film with a 3 nm thick alumina film an increase of both the real and the imaginary part of the dielectric function for all major polarizability directions is found and attributed to screening effects within the spatially coherent metal nanocolumns.

Original language	English (US)
Pages (from-to)	513-517
Number of pages	5
Journal	Applied Surface Science
Volume	421
DOIs	https://doi.org/10.1016/j.apsusc.2016.12.200
State	Published - Nov 1 2017

Keywords

Bruggeman effective medium
Generalized ellipsometry
Glancing angle deposition
Sculptured thin film
Terahertz

ASJC Scopus subject areas

General Chemistry
Condensed Matter Physics
General Physics and Astronomy
Surfaces and Interfaces
Surfaces, Coatings and Films

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10.1016/j.apsusc.2016.12.200

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title = "Screening effects in metal sculptured thin films studied with terahertz Mueller matrix ellipsometry",

abstract = "The anisotropic optical dielectric functions of a metal (cobalt) slanted columnar thin film deposited by electron-beam glancing angle deposition are reported for the terahertz (THz) frequency domain before and after the slanted columnar thin film was passivated by a conformal alumina coating. A simple effective medium dielectric function homogenization approach which describes isolated, electrically conductive columns rendering the thin film biaxial (orthorhombic) is used to model the observed optical responses. Upon passivating the slanted columnar thin film with a 3 nm thick alumina film an increase of both the real and the imaginary part of the dielectric function for all major polarizability directions is found and attributed to screening effects within the spatially coherent metal nanocolumns.",

keywords = "Bruggeman effective medium, Generalized ellipsometry, Glancing angle deposition, Sculptured thin film, Terahertz",

author = "T. Hofmann and S. Knight and D. Sekora and D. Schmidt and Herzinger, {C. M.} and Woollam, {J. A.} and E. Schubert and M. Schubert",

note = "Funding Information: This work was supported in part by the National Science Foundation (NSF) through the Nebraska Materials Research Science and Engineering Center (DMR 1420645) and the Center for Nanohybrid Functional Materials (EPS-1004094). The authors would like to acknowledge financial support from the Swedish Agency for Innovation Systems (2014-04712), the University of Nebraska-Lincoln, and the J.A. Woollam Foundation. Funding Information: This work was supported in part by the National Science Foundation (NSF) through the Nebraska Materials Research Science and Engineering Center (DMR 1420645) and the Center for Nanohybrid Functional Materials (EPS-1004094). The authors would like to acknowledge financial support from the Swedish Agency for Innovation Systems (2014-04712), the University of Nebraska-Lincoln, and the J.A. Woollam Foundation. Publisher Copyright: {\textcopyright} 2016 Elsevier B.V.",

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doi = "10.1016/j.apsusc.2016.12.200",

language = "English (US)",

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AU - Knight, S.

AU - Sekora, D.

AU - Schmidt, D.

AU - Herzinger, C. M.

AU - Woollam, J. A.

AU - Schubert, E.

AU - Schubert, M.

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PY - 2017/11/1

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N2 - The anisotropic optical dielectric functions of a metal (cobalt) slanted columnar thin film deposited by electron-beam glancing angle deposition are reported for the terahertz (THz) frequency domain before and after the slanted columnar thin film was passivated by a conformal alumina coating. A simple effective medium dielectric function homogenization approach which describes isolated, electrically conductive columns rendering the thin film biaxial (orthorhombic) is used to model the observed optical responses. Upon passivating the slanted columnar thin film with a 3 nm thick alumina film an increase of both the real and the imaginary part of the dielectric function for all major polarizability directions is found and attributed to screening effects within the spatially coherent metal nanocolumns.

AB - The anisotropic optical dielectric functions of a metal (cobalt) slanted columnar thin film deposited by electron-beam glancing angle deposition are reported for the terahertz (THz) frequency domain before and after the slanted columnar thin film was passivated by a conformal alumina coating. A simple effective medium dielectric function homogenization approach which describes isolated, electrically conductive columns rendering the thin film biaxial (orthorhombic) is used to model the observed optical responses. Upon passivating the slanted columnar thin film with a 3 nm thick alumina film an increase of both the real and the imaginary part of the dielectric function for all major polarizability directions is found and attributed to screening effects within the spatially coherent metal nanocolumns.

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KW - Generalized ellipsometry

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Screening effects in metal sculptured thin films studied with terahertz Mueller matrix ellipsometry

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Keywords

ASJC Scopus subject areas

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