Observation of Negative Contact Resistances in Graphene Field-Effect Transistors

Abstract

The gate-voltage (VG) dependence of the contact resistance (RC) in graphene field-effect transistors is characterized by the transmission line model. The RC-VG characteristics of Ag, Cu, and Au contacts display a dip around the charge neutrality point, and become even negative with Ag contacts. The dip structure is well reproduced by a model calculation that considers a metal-contact-induced potential variation near the metal contact edges. The apparently negative RC originates with the carrier doping from the metal contacts to the graphene channel and appears when the doping effect is more substantial than the actual contact resistance precisely at the contacts. The negative RC can appear at the metal contacts to Dirac-cone systems such as graphene.

7 figures, 1 table

References in corpus (5)

• The electronic properties of graphene
• Giant Intrinsic Carrier Mobilities in Graphene and Its Bilayer
• Evidence of the role of contacts on the observed electron-hole asymmetry in graphene
• Charge-density depinning at metal contacts of graphene field-effect transistors
• Determination of Carrier Type Doped from Metal Contacts to Graphene by Channel-Length-Dependent Shift of Charge Neutrality Points

Cited by in corpus (4)

• Path of the current flow at the metal contacts of graphene field-effect transistors with distorted transfer characteristics
• Reversible doping of graphene field effect transistors by molecular hydrogen: the role of the metal/graphene interface
• Experimental signature of bandgap opening in bilayer graphene at metal contacts
• Contact resistance at planar metal contacts on bilayer graphene and effects of molecular insertion layers