Raman Spectra of Vertical Graphene Nanosheets*

Raman spectroscopy studies have been demonstrated their importance in providing a quantitative measure on different carbon-based samples, such as graphene, carbon nanotube, and sp3 amorphous carbon. Recently, plasma-enhanced chemical vapor deposition grown vertical graphene nanosheets (VGNs) have attracted much attention owing to their abundant edges, surface, and enhanced electrochemical activity, which are potentially applicable to a wide of fields. However, due to its complexity of the vertical structures, the knowledge gained in previous carbon-based materials has not fully been extended to VGNs. In this work, we review the recent advance of Raman characterization results on PECVD-grown VGNs. With the insights from interference in graphene nanosheets and their electrical field distribution, we are able to extend the knowledge from the Raman spectroscopy of conventionally flat graphene layer to vertical graphene nanosheets. A feasible way to distinguish and evaluate the quality and structures of the VGNs from Raman spectra is presented in combination with the transmission electron microscopy characterization.