Physical Investigation of electrophoretically deposited Graphene Oxide and Reduced Graphene Oxide Thin Films

Graphene oxide and reduced graphene oxide thin films are very promising materials because they can be used in optoelectronic devices and in a growing range of applications such as touch screens and flexible displays. In this work graphene oxide (GO) and thermally reduced graphene oxide (rGO) thin films, deposited on Ti/glass substrates, have been obtained by Electrophoretic deposition (EPD). The morphologic and the structural properties of the samples have been investigated by micro-Raman technique, X-ray reflectometry and SEM analysis . In order to study the optical and electrical properties, variable angle spectroscopic ellipsometry and impedance analysis have been performed. The thermal annealing changes strongly the structural, electrical and optical properties, because during the thermal processes some amount of sp3 bonds originally present in GO were removed. In particular, the annealing enhances the Ohmic behavior of rGO film increasing its conductivity and the estimated optical density. Moreover, using electrophoretic deposition we have found a higher value of optical density for GO thin films , not observed in GO films obtained with other deposition methods.