Fabricating vertically aligned ultrathin graphene nanosheets without any catalyst using rf sputtering deposition

Ultrathin graphene nanosheets (GNSs) were synthesized on Si substrates by using radio frequency sputtering deposition. SEM, TEM and Raman were employed to characterize the GNSs. The GNSs are well aligned on the Si substrates with sharp edges separated and unfolded outside. The TEM observation shows that most of the GNSs are less than 10 layers. The field emission properties of the GNSs synthesized for 10 h were also studied. They show good field emission characteristics, with a low turn-on electric field of 2.522 V/μm, a large field enhancement factor, and excellent stability behavior, suggesting promising prospects in the application of field electron emitting devices.