SUPPORTING INFORMATION – Effect of Dry Oxidation on the Energy Gap and Chemical
Composition of CVD Graphene on Nickel
Figure S1. Schematic of the surface treatment and characterization performed in this study.
Here, the surface treatment was done by a combination of UV/ozone or oxygen plasma and
vacuum annealing treatments, and the characterization was performed using STM/STS and XPS.
Figure S2. Typical high resolution O 1s XPS spectra of CVD graphene on nickel after being
exposed to a prolonged oxidation treatment, i.e. (a) after 15 seconds of oxygen plasma treatment
and (b) after 15 minutes of UV/ozone treatment. An oxygen uptake by nickel layer can be seen
from a weak peak associated with NiO and Ni(OH)2.
Figure S3. Atomically resolved STM images of CVD graphene on nickel after being exposed to
a prolonged oxidation treatment, i.e. (a) after 15 seconds of oxygen plasma treatment and (b)
after 15 minutes of UV/ozone treatment. In both images, the periodic hexagonal lattice structure
is heavily distorted.