Experimental signature of bandgap opening in bilayer graphene at metal contacts
arXiv:1412.1202 · doi:10.1063/1.4903249
Abstract
Bilayer graphene (BLG) possesses a finite bandgap when a potential difference is introduced between the two graphene layers. The potential difference is known to be introduced by surface charge transfer. Thus, it is expected that a finite bandgap exists at the metal contacts. The bandgap at the metal-BLG interface can be detected by the superlinear current-voltage characteristics in back-gate field-effect transistors, caused by carriers tunneling through the bandgap. The superlinearity was higher in the positively gated region, attributed to hole doping from the Cr/Au electrodes. The control experiments using single-layer graphene (SLG) did not have a superlinearity, which is consistent with the fact that a sizeable bandgap is not expected at the metal-SLG interface. The opening of a bandgap at the metal-BLG interface is an additional source of electrode-contact resistance.
14 pages, 5 figures
References in corpus (16)
- Energy Band Gap Engineering of Graphene Nanoribbons
- Energy Gaps in Graphene Nanoribbons
- Giant Intrinsic Carrier Mobilities in Graphene and Its Bilayer
- Biased bilayer graphene: semiconductor with a gap tunable by electric field effect
- Gate-induced insulating state in bilayer graphene devices
- Graphene Nano-Ribbon Electronics
- Carrier transport in 2D graphene layers
- Ab Initio Theory of Gate Induced Gaps in Graphene Bilayers
- Evidence of the role of contacts on the observed electron-hole asymmetry in graphene
- Determination of the electronic structure of bilayer graphene from infrared spectroscopy results
- The environment of graphene probed by electrostatic force microscopy
- Inter-Layer Screening Length to Electric Field in Thin Graphite Film
- 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
- Observation of Negative Contact Resistances in Graphene Field-Effect Transistors
- Path of the current flow at the metal contacts of graphene field-effect transistors with distorted transfer characteristics