We report a Variable Angle Spectroscopic Ellipsometry (VASE) characterization of the surface of CVD-grown bilayer and trilayer graphene produced by multiple transfer on SiO2/Si and polyethylene terephthalate (PET) substrates. The graphene layers are randomly stacked. The study of the optical properties of single- and few-layer graphene on PET by means of VASE, which has not been published yet, could be useful in the light of novel graphene-based flexibleand stretchable electronics applications. The Lorentz models proposed for the optical response of bilayer and trilayer graphene samples fitvery well the experimental data. Some interesting properties have been observed. A never-before-reported absorption peak at e3 eV on bilayer and trilayer graphene on SiO2/Si is discussed. The absorption peak due to resonant excitons has been found at e4.4 eV on bilayer graphene on SiO2/Si and its value is red-shifted from e4.6 eV in monolayer graphene toe4.4 eV in bilayer graphene. This peak shift has not been observed on bilayer graphene on PET substrates.
Variable angle spectroscopic ellipsometry characterization of turbostratic CVD-grown bilayer and trilayer graphene
Giovanni Desiderio;Carlo Versace
2020
Abstract
We report a Variable Angle Spectroscopic Ellipsometry (VASE) characterization of the surface of CVD-grown bilayer and trilayer graphene produced by multiple transfer on SiO2/Si and polyethylene terephthalate (PET) substrates. The graphene layers are randomly stacked. The study of the optical properties of single- and few-layer graphene on PET by means of VASE, which has not been published yet, could be useful in the light of novel graphene-based flexibleand stretchable electronics applications. The Lorentz models proposed for the optical response of bilayer and trilayer graphene samples fitvery well the experimental data. Some interesting properties have been observed. A never-before-reported absorption peak at e3 eV on bilayer and trilayer graphene on SiO2/Si is discussed. The absorption peak due to resonant excitons has been found at e4.4 eV on bilayer graphene on SiO2/Si and its value is red-shifted from e4.6 eV in monolayer graphene toe4.4 eV in bilayer graphene. This peak shift has not been observed on bilayer graphene on PET substrates.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.