Figure 3
From: High accuracy determination of the thermal properties of supported 2D materials
(a) Feature in the Raman spectrum, called G mode, characteristic for sp2 carbons and illustrating the distribution of the TO + LO phonon energies (tangential and longitudinal optical modes are usually degenerated in the Γ point; therefore, the energy distribution can be fitted with a single Lorentzian function). (b) Optical image of a 5-nm thick exfoliated multilayer graphene flake on the Si/SiO2 substrate for one of the examined samples. Dependence of the Raman G mode energy from (c) temperature taken in the PL → 0 limit, (d) the power of the laser beam illuminating the sample taken at T = 300 K and (e) the distance of the thin film surface from the laser beam focus for seven laser power values (from 5 mW to 11 mW in equal steps). Inset: derivative of the G mode energy over the laser power.
