Charge-density depinning at metal contacts of graphene field-effect transistors

Abstract

An anomalous distortion is often observed in the transfer characteristics of graphene field-effect transistors. We fabricate graphene transistors with ferromagnetic metal electrodes, which reproducibly display distorted transfer characteristics, and show that the distortion is caused by metal-graphene contacts with no charge-density pinning effect. The pinning effect, where the gate voltage cannot tune the charge density of graphene at the metal electrodes, has been experimentally observed; however, a pinning-free interface is achieved with easily-oxidizable metals. The distortion should be a serious problem for flexible electronic devices with graphene.

To be published in Appl. Phys. Lett

References in corpus (9)

• The electronic properties of graphene
• Doping graphene with metal contacts
• Atomic Structure of Graphene on SiO2
• Transport measurements across a tunable potential barrier in graphene
• Evidence of the role of contacts on the observed electron-hole asymmetry in graphene
• Effective contact model for transport through weakly-doped graphene
• Inter-Layer Screening Length to Electric Field in Thin Graphite Film
• Electronic transport in normal-conductor/graphene/normal-conductor junctions and conditions for insulating behavior at a finite charge-carrier density
• Transfer Characteristics in Graphene Field-Effect Transistors with Co Contacts

Cited by in corpus (10)

• Electrically Controlled Adsorption of Oxygen in Bilayer Graphene Devices
• Direct electronic measurement of Peltier cooling and heating in graphene
• Suppression of contact-induced spin dephasing in graphene/MgO/Co spin-valve devices by successive oxygen treatments
• Determination of Carrier Type Doped from Metal Contacts to Graphene by Channel-Length-Dependent Shift of Charge Neutrality Points
• Observation of Negative Contact Resistances in Graphene Field-Effect Transistors
• Electron-hole asymmetry in two-terminal graphene devices
• Competitive interfacial charge transfer to graphene from the electrode contacts and surface adsorbates
• 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