Competitive interfacial charge transfer to graphene from the electrode contacts and surface adsorbates
arXiv:1503.00393 · doi:10.1063/1.4913669
Abstract
Charge transfer (CT) at metal-graphene contacts induces a potential variation from the contact edges that extends to ~1 micrometer. Potential variations with a similar length should be observed around charge-transferring surface adsorbates. Thus, it is expected that a competition exists between these two CT sources when one source is within ~1 micrometer from the other. In this letter, weakly-coupled Ni contacts and 7,7,8,8-tetracyanoquinodimethan molecules are employed as the CT sources to investigate their possible competition. The CT from the molecules adsorbed only in the channel region change the charge density of the graphene in the under-contact regions. The extent of the CT effect in the under-contact region is as long as ~4 micrometers. The considerably long CT is ascribed to the high effective dielectric constant of the graphene under the contacts, resulting from a thin interfacial NiOx layer containing carbon impurities acquired from the graphene.
13 pages, 4 figures
References in corpus (8)
- Detection of Individual Gas Molecules Absorbed on Graphene
- Doping graphene with metal contacts
- Evidence of the role of contacts on the observed electron-hole asymmetry in graphene
- Direct Experimental Evidence of Metal-Mediated Etching of Suspended Graphene
- Effects of metallic contacts on electron transport through 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
- Path of the current flow at the metal contacts of graphene field-effect transistors with distorted transfer characteristics