  Recent progress in the on-surface synthesis of graphene nanoribbons (GNRs)
has given access to atomically precise narrow GNRs with tunable electronic band
gaps that makes them excellent candidates for room-temperature switching
devices such as field-effect transistors (FET). However, in spite of their
exceptional properties, significant challenges remain for GNR processing and
characterization. This contribution addresses some of the most important
challenges, including GNR fabrication scalability, substrate transfer,
long-term stability under ambient conditions and ex situ characterization. We
focus on 7- and 9-atom wide armchair graphene nanoribbons (i.e, 7-AGNR; and
9-AGNR) grown on 200 nm Au(111)/mica substrates using a high throughput system.
Transfer of both, 7- and 9-AGNRs from their Au growth sub-strate onto various
target substrates for additional characterization is accomplished utilizing a
polymer-free method that avoids residual contamination. This results in a
homogeneous GNR film morphology with very few tears and wrinkles, as examined
by atomic force microscopy. Raman spectroscopy indicates no significant
degradation of GNR quality upon substrate transfer, and reveals that GNRs have
remarkable stability under ambient conditions over a 24-month period. The
transferred GNRs are analyzed using multi-wavelength Raman spectroscopy, which
provides detailed insight into the wavelength dependence of the width-specific
vibrational modes. Finally, we characterize the optical properties of 7- and
9-AGNRs via ultra-violet-visible (UV-Vis) spectroscopy
