Figure 1 : Surface-transfer n-doping of graphene from Na.

From: Spontaneous and strong multi-layer graphene n-doping on soda-lime glass and its application in graphene-semiconductor junctions

Figure 1

(A) Conductance (G) (normalized) vs. gate-voltage (VG) of graphene (GR)/soda-lime glass (SLG) and GR/borosilicate-glass (BSG) (inset) measured in FET configuration (schematic). (B) DFT calculated dispersion curve showing n-doping in graphene interacting with Na. (C) Na and Se depth-profiles in CIGS/Mo/SLG and CIGS/Mo/BSG from TOF-SIMS. (D) Cross-sectional HR-TEM of GR/CIGS/Mo/SLG. (E) Raman spectrograph of GR/CIGS/Mo/SLG showing E0 peak of CuIn0.7Ga0.3Se2 (177 cm−1), and G peak (1585 cm−1) and 2D peak (2665 cm−1) of graphene. (F) EDS maps of GR/CIGS/Mo/SLG showing Na (yellow, top) and C (purple, bottom). (G) Schematic of graphene n-doping mechanism on CIGS.