Determination of the Optical Index for Few-Layer Graphene by Reflectivity Spectroscopy
Abstract
We have experimentally studied the optical refractive index of few-layer graphene through reflection spectroscopy at visible wavelengths. A laser scanning microscope (LSM) with a coherent supercontinuum laser source measured the reflectivity of an exfoliated graphene flake on a Si/SiO2 substrate, containing monolayer, bilayer and trilayer areas, as the wavelength of the laser was varied from 545nm to 710nm. The complex refractive index of few-layer graphene, n-ik, was extracted from the reflectivity contrast to the bare substrate and the Fresnel reflection theory. Since the SiO2 thickness enters to the modeling as a parameter, it was precisely measured at the location of the sample. It was found that a common constant optical index cannot explain the wavelength-dependent reflectivity data for single-, double- and three-layer graphene simultaneously, but rather each individual few-layer graphene possesses a unique optical index whose complex values were precisely and accurately determined from the experimental data.
Keywords
Cite
@article{arxiv.1210.0575,
title = {Determination of the Optical Index for Few-Layer Graphene by Reflectivity Spectroscopy},
author = {Behnood G. Ghamsari and Jacob Tosado and Mahito Yamamoto and Michael S. Fuhrer and Steven M. Anlage},
journal= {arXiv preprint arXiv:1210.0575},
year = {2016}
}