Figure 4From: A Study on Field Emission Characteristics of Planar Graphene Layers Obtained from a Highly Oriented Pyrolyzed Graphite BlockGraphene samplea optical image of graphene sheets on SiO2. Thecolor of graphene sheets determines thickness of the graphene layer.Scale bar: 6 μm.b SEM image of a graphene sample with tungsten tips controlled by nanomanipulatorBack to article page