Figure 2
Characterization the graphene layers of 3D-GMOs.
(a) Typical Raman spectra of 3D-GMOs grown with different temperatures for 1.5 min. The Raman spectra show that the quality of 3D-GMOs is gradually improved with increasing the growth temperature up to 1000°C. (b) Typical Raman spectra of a 3D-GMO. Multi-layer, bilayer and monolayer graphene from bottom to top estimated by the intensity ratio of 2D peak to G peak, combining with 2D-band full-width at half maximum (FWHM, W2D). (c) A photograph of the free-standing 3D-GMO. (d, e) SEM images of honeycomb-like graphene layers after etching Ni template with FeCl3/HCl solution at different magnifications. (f) Low-resolution TEM image of the graphene layers in a 3D-GMO. (g–k) High resolution TEM images of different graphene layers in a 3D-GMO. (g) Monolayer. (h) Double layers and four layers. (i) Three layers. (j) Seven layers. (k) Ten layers.
