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Title: An improved thin film approximation to accurately determine the optical conductivity of graphene from infrared transmittance

This work presents an improved thin film approximation to extract the optical conductivity from infrared transmittance in a simple yet accurate way. This approximation takes into account the incoherent reflections from the backside of the substrate. These reflections are shown to have a significant effect on the extracted optical conductivity and hence on derived parameters as carrier mobility and density. By excluding the backside reflections, the error for these parameters for typical chemical vapor deposited (CVD) graphene on a silicon substrate can be as high as 17% and 45% for the carrier mobility and density, respectively. For the mid- and near-infrared, the approximation can be simplified such that the real part of the optical conductivity is extracted without the need for a parameterization of the optical conductivity. This direct extraction is shown for Fourier transform infrared (FTIR) transmittance measurements of CVD graphene on silicon in the photon energy range of 370–7000 cm{sup −1}. From the real part of the optical conductivity, the carrier density, mobility, and number of graphene layers are determined but also residue, originating from the graphene transfer, is detected. FTIR transmittance analyzed with the improved thin film approximation is shown to be a non-invasive, easy, and accurate measurementmore » and analysis method for assessing the quality of graphene and can be used for other 2-D materials.« less
Authors:
;  [1] ;  [1] ;  [2]
  1. Department of Applied Physics, Eindhoven University of Technology, Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven (Netherlands)
  2. (DIFFER), Nieuwegein (Netherlands)
Publication Date:
OSTI Identifier:
22303950
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 1; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; APPROXIMATIONS; CARRIER DENSITY; CARRIER MOBILITY; CHEMICAL VAPOR DEPOSITION; EXTRACTION; FOURIER TRANSFORMATION; GRAPHENE; INFRARED SPECTRA; LAYERS; PHOTONS; REFLECTION; SILICON; SUBSTRATES; THIN FILMS