| 초록 |
We report the reliable surface oxidation of the graphene grown by chemical vapor deposition using potassium permanganate (KMnO4)/diluted sulfuric acid (H2SO4). The oxidized graphene has no pores. As increasing H2SO4 concentrations, it rises to the degree of the epoxide/hydroxyl, carbonyl, and carboxyl groups, and the distance between defects in the oxidized graphene is reduced. Based on the graphene oxidation technology, the graphene/oxidized graphene/graphene field-effect transistor (GOG-FET) with lateral heterostructures is fabricated and characterized using current-voltage measurement. The GOG-FET shows a nonlinear diode curve with the on-off switching ratio ＞ 104, which is owing to the direct tunneling through the interfaces between nano-sized sp2 (electrically conductive region) and sp3 (electrically insulated region) areas in oxidized graphene. In addition, it presents p-type behavior by the adsorbed oxygen molecules on the surface. Hence, our wet-based oxidation technique devotes the mass-production of graphene-based electronic devices owing to the simplicity and inexpensive fabrication method. |
