nl6b01657_si_001.pdf (351.27 kB)
Resistivity of Rotated Graphite–Graphene Contacts
journal contribution
posted on 2016-05-31, 00:00 authored by Tarun Chari, Rebeca Ribeiro-Palau, Cory R. Dean, Kenneth ShepardRobust
electrical contact of bulk conductors to two-dimensional (2D) material,
such as graphene, is critical to the use of these 2D materials in
practical electronic devices. Typical metallic contacts to graphene,
whether edge or areal, yield a resistivity of no better than 100 Ω
μm but are typically >10 kΩ μm. In this Letter,
we employ single-crystal graphite for the bulk contact to graphene
instead of conventional metals. The graphite contacts exhibit a transfer
length up to four-times longer than in conventional metallic contacts.
Furthermore, we are able to drive the contact resistivity to as little
as 6.6 Ω μm2 by tuning the relative orientation
of the graphite and graphene crystals. We find that the contact resistivity
exhibits a 60° periodicity corresponding to crystal symmetry
with additional sharp decreases around 22° and 39°, which
are among the commensurate angles of twisted bilayer graphene.