Variable-Angle Spectroscopic Ellipsometry of Graphene-Based Films

A review of the authors’ research works on Variable-Angle Spectroscopy (VASE) of graphene-based films is presented. The interaction of graphene oxide (GO) with magnetron-sputtered metals is a promising research area. VASE optical models of GO thin films deposited on magnetron-sputtered titanium (Ti), silver (Ag) and gold (Au) are discussed. Moreover, the optical properties of graphene nanoplatelet (GNPS) films and reduced graphene oxide (RGO) stabilized with Poly(Sodium 4-Styrenesulfonate) (PSS) films, which are less studied graphene-related materials, are shown. Finally, different optical behaviors of chemical vapor deposition (CVD)-grown monolayer, bilayer, and trilayer graphene films on silicon and polyethylene terephthalate (PET) substrates are recapitulated.

Variable Angle Spectroscopic Ellipsometry Characterization of Reduced Graphene Oxide Stabilized with Poly(Sodium 4-Styrenesulfonate)

Lately, the optical properties of Graphene Oxide (GO) and Reduced Graphene Oxide (RGO) films have been studied in the ultraviolet and visible spectral range. However, the accurate optical properties in the extended near-infrared and mid-infrared range have not been published yet. In this work, we report a Variable Angle Spectroscopic Ellipsometry (VASE) characterization of GO thin films dip-coated on SiO2/Si substrates and thermally reduced GO films in the 0.38–4.1 eV photon energy range. Moreover, the optical properties of RGO stabilized with poly(sodium 4-styrenesulfonate) (PSS) films dip-coated on SiO2/Si substrates are studied in the same range for the first time. The Lorentz optical models fit well with the experimental data. In addition, the morphological properties of the samples were investigated by Scanning Electron Microscopy (SEM) analysis.