Optical properties of various graphitic structures deposited by PECVD

In this article, we report on the comparative study of the optical properties of different graphitic structures such as stacked graphite (GR), graphene oxide (GO) and few-layers of graphene (FLG). Plasma enhanced chemical vapour deposition technique employing acetylene (C2H2) as precursor gas used to deposit the different graphitic nanosheets on copper substrates. The influence of mixture gas ratio (C2H2/H2) on the structure of nanosheet was examined. Investigation of detailed structure of nanosheets was performed by different characterization techniques such as X-ray diffraction, attenuated total reflectance-Föurier transform infrared and Raman spectroscopy. Optical properties of stacked graphite, graphene oxide and few layers of graphene sheets were studied. The present results reveal that how the optical properties change due to the variations in structure parameters of sheets. The refractive index results indicate the anomalous dispersion due to strong absorption featured for graphitic structures. The real dielectric constant of GR and FLG sheets reveals independent frequency behavior and approach to zero but GO sheet shows a broadband peak from 1.75 to 4.75 eV which attributed to oxygen functional group behavior.