Evaluation of the interlayer interactions of few layers of graphene

We examined the number of layers in graphene using Raman microscopy and investigated the interlayer interactions by understanding the layer stacking through the E∗(low) mode measured in Raman spectroscopy designed for low-frequency observation. The number of layers in Raman image was determined from the G/2D intensity ratio, and the interlayer stacking for 2, 3 and 4 layers was understood from the positions of the E∗(low) mode. While most part of sample showed AB stacking, a small area showed random stacking of layers. Low-frequency Raman spectroscopy revealed that such sample area was consisted of weakly interacted random stacking of graphene layers.