Raman spectra collected in the middle of the terraces (5 to 6 layers) and on the stripes close to the step edges (11 layers). No D band can be observed confirming the excellent crystalline quality of these FLG. The asymmetric shape of the 2D band (that is more pronounced for the thicker FLG) reveals a Bernal stacking of the graphene planes. Finally, both bands are blue-shifted. Such shift can only be explained by a compressive strain of the graphene lattice coming from the differential dilatation during the cooling down of the sample. A partial strain relaxation occurs for thicker FLG since the thicker the less shifted.
Tiberj et al. Nanoscale Research Letters 2011 6:478 doi:10.1186/1556-276X-6-478