Two-dimensional Raman intensity map for bilayer graphene. (a) I2D/IG ratio (ratio of 2D to G peak intensities). (b) I2D (intensity of 2D peak). (c) IG (intensity of G peak). (d), (e) and (f) show I2D/IG, I2D and IG, respectively, for a different area. BLG was grown by using CVD on 300-nm of evaporated Ni film under CH4/Ar (23:200 sccm) at 1,000°C for 120 s. The total area of each view map is 200 μm × 200 μm.
Umair and Raza Nanoscale Research Letters 2012 7:437 doi:10.1186/1556-276X-7-437