  We present a route to non-destructive functionalization of graphene via
assembly of vertical all-carbon van der Waals heterostructures. To this end, we
employ singlelayer graphene (SLG) sheets grown by low-pressure methane CVD on
Cu foils and large-area dielectric ~1 nm thick amino-terminated carbon
nanomembranes (NH2-CNMs) generated by electron-beam-induced crosslinking of
aromatic self-assembled monolayers. We encapsulate SLG sheets on oxidized
silicon wafers with NH2-CNMs via mechanical stacking and characterize
structural, chemical and electronic properties of the formed heterostructures
by Raman spectroscopy and X-ray photoelectron spectroscopy as well as by
electric and electromagnetic transport measurements. We show that functional
amino groups are brought in close vicinity of the SLG sheets and that their
transport characteristics are not impaired by this functionalization; moreover,
we demonstrate a functional response of the heterostructure devices to the
protonation of the amino groups in water. Due to its relative simplicity, the
suggested approach opens broad avenues for implementations in graphene-based
electronic devices where non-destructive chemical functionalization of graphene
is required (e.g., for engineering electrical transducers for chemical and
bio-sensing) or as complementary dielectric to graphene in hieratical
heterostructures.
