Fig. 3
From: Redox-governed charge doping dictated by interfacial diffusion in two-dimensional materials
Amplification and suppression of redox reactions. a Raman spectra of pristine (black), thermally activated (red; annealed at 500 °C), and deactivated (blue; annealed at 1000 °C) 1L graphene (1LGsilica). b Correlation between G and 2D frequencies of 1LGsilica samples annealed at various temperatures (in °C; given next to data). Lattice strain (ε) and electrical hole density (nh) were determined according to ref. 22. c Changes in lattice strain (top) and hole-density (middle) of graphene; water-contact angle (bottom) of SiO2 substrates as a function of annealing temperature (T). Error bars denote standard deviation. d Optical micrographs (left) and charge-density images (right) of 1LGsilica samples prepared on diethyl zinc-treated (top) and non-treated (bottom) substrates. Both samples were activated by annealing at 400 °C. Scale bars: 10 μm. e Schematic representation of air-equilibrated graphene–SiO2 interface: pristine (left), hydroxylated by thermal activation (middle), and dehydroxylated by thermal deactivation (right). Equilibrium coverage of interfacial water was determined by effective hydrophilicity of SiO2 substrates
