  Single-layer graphene structures and devices are commonly defined using
reactive ion etching and plasma etching with O2 or Ar as the gaseous etchants.
Although optical microscopy and Raman spectroscopy are widely used to determine
the appropriate duration of dry etching, additional characterization with
atomic force microscopy (AFM) reveals that residual graphene and/or etching
byproducts persist beyond the point where the aforementioned methods suggest
complete graphene etching. Recognizing that incomplete etching may have
deleterious effects on devices and/or downstream processing, AFM
characterization is used here to determine optimal etching conditions that
eliminate graphene dry etching residues.
