In this work, we have examined the optical properties of exfoliated graphene on an substrate using spectroscopic imaging ellipsometry in the visible range (360–800 nm). Measured spectra were analyzed by an optical model based on the Fresnel coefficient equations. The optical model was supported by correlated Raman and atomic force microscopy measurements. The complex refractive index of graphene was obtained by inversion of the measured ellipsometry data. The Fano line-shape was used to parameterize the optical properties. Measurements were highly reliable due to the numerous advantages of the spectroscopic imaging ellipsometric technique combined with the proper choice of substrate and experimental set-up. Thickness maps of the graphene sample were obtained from spatially resolved imaging ellipsometry spectra with a spot size of 1 μm. The data showed the presence of a water layer on the surface of the sample, and the thickness was mapped showing the distribution of water over graphene in ambient conditions.
Spectroscopic imaging ellipsometry and Fano resonance modeling of graphene
Aleksandar Matković, Angela Beltaos, Marijana Milićević, Uroš Ralević, Borislav Vasić, Djordje Jovanović, Radoš Gajić; Spectroscopic imaging ellipsometry and Fano resonance modeling of graphene. J. Appl. Phys. 15 December 2012; 112 (12): 123523. https://doi.org/10.1063/1.4771875
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