Simultaneous Etching and Doping by Cu-Stabilizing Agent for High- Performance Graphene-Based Transparent Electrodes

Cu etching is one of the key processes to produce large-area graphene through chemical vapor deposition (CVD), which is needed to remove Cu catalysts and transfer graphene onto target substrates for further applications. However, the Cu etching method has been much less studied compared to doping or transfer processes despite its importance in producing higher quality graphene films. The Cu etchant generally includes a strong oxidizing agent that converts metallic Cu to Cu2+ in a short period of time. Sometimes, the highly concentrated Cu2+ causes a side reaction leading to defect formation on graphene, which needs to be suppressed for higher graphene quality. Here we report that the addition of metal-chelating agents such as benzimidazole (BI) to etching solution reduces the reactivity of Cu-etching solution by forming a coordination compound between BI and Cu2+. The resulting graphene film prepared by Cu stabilizing agent exhibits a sheet resistance as lows as ∼200 Ohm/sq without additional doping proce...