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Title: Structural and optical properties of cobalt slanted nanopillars conformally coated with few-layer graphene

Optical characterization of anisotropic multicomponent nanostructures is generally not a trivial task, since the relation between a material's structural properties and its permittivity tensor is nonlinear. In this regard, an array of slanted cobalt nanopillars that are conformally coated with few-layer graphene is a particularly challenging object for optical characterization, as it has a complex anisotropic geometry and comprises several materials with different topologies and filling fractions. Normally, a detailed characterization of such complex nanostructures would require a combination of several microscopic and spectroscopic techniques. In this letter, we demonstrate that the important structural parameters of these graphene-coated sculptured thin films can be determined using a fast and simple generalized spectroscopic ellipsometry test combined with an anisotropic Bruggeman effective medium approximation. The graphene coverage as well as structural parameters of nanostructured thin films agree excellently with electron microscopy and Raman spectroscopy observations. The demonstrated optical approach may also be applied to the characterization of other nanostructured materials.
Authors:
;  [1] ;  [2] ;  [3] ; ; ;  [2] ;  [3] ;  [3] ;  [1] ;  [3] ;  [3]
  1. Department of Chemistry, University of Nebraska—Lincoln, Lincoln, Nebraska 68588 (United States)
  2. Department of Electrical and Computer Engineering, University of Nebraska—Lincoln, Lincoln, Nebraska 68588 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22412550
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 23; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; COBALT; ELECTRON MICROSCOPY; GRAPHENE; LAYERS; NANOSTRUCTURES; OPTICAL PROPERTIES; PERMITTIVITY; RAMAN SPECTROSCOPY; THIN FILMS