We analyzed the effect of etchants for metal catalysts in terms of the characteristics of resulting graphene films, such as sheet resistance, hall mobility, transmittance, and carrier concentration. We found the residue of FeCl3 etchant degraded the sheet resistance and mobility of graphene films. The residue was identified as an iron oxide containing a small amount of Cl through elemental analysis using X-ray photoelectron spectroscopy. To remove this residue, we provide an alternative etching solution by introducing acidic etching solutions and their combinations (HNO3, HCl, FeCl3 + HCl, and FeCl3+HNO3). The combination of FeCl3 and acidic solutions (HCl and HNO3) resulted in more enhanced electrical properties than pure etchants, which is attributed to the elimination of left over etching residue, and a small amount of amorphous carbon debris after the etching process.

• Hong-Kyw Choi(Creative Research Center for Graphene Electronics, Electronics and Telecommunications Research Insititute and Advanced Device Technology Major, University of Science and Technology)
• Jong-Yun Kim(Department of Electrical Engineering, Korea Advanced Institute of Science and Technology)
• Hu-Young Jeong(Centeral Research Facilities, Ulsan National Institute of Science and Technology)
• Choon-Gi Choi(Creative Research Center for Graphene Electronics, Electronics and Telecommunications Research Insititute and Advanced Device Technology Major, University of Science and Technology)
• Sung-Yool Choi(Department of Electrical Engineering, Korea Advanced Institute of Science and Technology) Corresponding Author