| Summary: | We report the electrical properties of graphene grown via chemical vapor deposition (CVD-graphene) and oxidized using a KMnO<sub>4</sub>/dilute H<sub>2</sub>SO<sub>4</sub> mixture. CVD-graphene was successfully oxidized without any pores or peeling off from the substrates. When the H<sub>2</sub>SO<sub>4</sub> concentration was increased, the electrical resistance of the oxidized graphene (OG) increased. In particular, OG-20 shows a nonlinear current–voltage curve similar to that of a diode owing to direct tunneling through the interfaces between the nanosized sp<sup>2</sup> and sp<sup>3</sup> regions. The changes in electrical properties occurred because of structural evolution. As the H<sub>2</sub>SO<sub>4</sub> concentration increased, the number of oxygen functional groups (epoxide/hydroxyl and carboxyl groups) in the OG increased. In addition, a reduction in the average distance between defects in the OG was determined using Raman spectroscopy. Oxidation using a KMnO<sub>4</sub>/dilute H<sub>2</sub>SO<sub>4</sub> mixture results in CVD-graphene with modified electrical properties for graphene-based applications.
|
|---|