Figure 1. UPS and XPS spectrum of pristine or n-type doped monolayer graphene on SiO2.
(a) The cut off and (b) valance band spectra of pristine, Cs2CO3-doped, and CsF-doped monolayer graphene. (c) The XPS spectra of C 1s peak of pristine, Cs2CO3-doped, and CsF-doped monolayer graphene.