Electrical and optical properties and applications of doped graphene sheets

Abstract

Graphene, a single layer of sp2-bonded carbon atoms, has attracted much attention due to its unique physical properties. The electronic properties of graphene sheets have recently attracted strong experimental and theoretical interest. Recently, large-area graphene sheets were successfully synthesized by chemical vapor deposition. One of the most attractive applica tions of large-scale graphene is as flexible transparent conduct ing films for electronic devices. For application to a large-area, flexible transparent conducting electrode, many research ers have focused on the synthesis of graphene with a high transmittance (>90%) and low sheet resistance (<200). Transmittance and sheet resistance have become acceptable for replacing commercial transparent conducting electrodes such as indium tin oxide (ITO). Even though graphene was reported to be used as a transparent electrode in optoelectronic devices, graphene-based devices have usually underperformed relative to ITO-based ones. One of these problems was induced by the energy level difference between the graphene electrode and the other active layers in electronic devices. Therefore, modula tion of the work function in the graphene layer is crucial for improving device performances. This chapter reviews the elec trical and optical properties of graphene from the viewpoint of transparent conducting electrodes. © 2016 by Taylor & Francis Group, LLC.