Co-Localized Characterization of Aged and Transferred CVD Graphene with Scanning Electron Microscopy, Atomic Force Microscopy, and Raman Spectroscopy

Abstract

Characterization plays an important role in graphene development for its effective synthesis and resultant application. In regards to characterization, microscopy shows the morphology of materials and spectroscopy provides information regarding bonding and crystal structure. Here, scanning electron microscopy, atomic force microscopy, and Raman spectroscopy are combined to co-localize and characterize aged and transferred graphene synthesized by the Cu-based chemical vapor deposition method. The combined investigation reveals the correlation between morphology and structure along with highlighting unique features that result from aging and transfer. The aged graphene on Cu may show the features of graphene adlayers under scanning electron microscopy, which in fact is due to the oxidation of Cu. The D band of the Raman spectrum is sometimes related to wrinkles, including the small ones that can only be detected by atomic force microscopy or standard optical microscopy. In addition to the thermally induced wrinkles, transfer may or may not induce ripples due to the replication of substrate surface morphology by the carrier film, which in turn is dependent upon the heights of the Cu steps. All these findings are of great significance to correctly understand the characterization results and promote the development of high-quality graphene film preparation technology.