Conductivity Modification of Reduced Graphene Oxide (rGO)

Abstract

In the traditional circuit board metallization process, the electroless plating process is the most common, but it contains precious metals (such as palladium catalyst), formaldehyde and chelating agents which can cause a serious environmental problem. However, the direct reduction process of graphene oxide (GO) does not include the toxic as mentioned above. In additionally, reduced GO (rGO) can be regarded as a direct plating process (i.e., without electroless deposition before copper electroplating) is simpler than electroless plating process and can replace the electroless plating process to achieve a green metallization process. Although rGO is a good electric conductor, copper is difficult directionally deposited on it due to its p-electron characteristics, which transfers only in X-Y two-dimensions. Therefore, when rGO is electroplated in a copper electroplating solution, the deposited copper crawls initially from the cathodic terminal and then fully cover the rGO-coated substrate if the surface area of the substrate is large. In this work, we propose an approach to enhance the conductivity of rGO in Z-direction, so that rGO will have three-dimensional conductivity to meet the industrial requirement.