High-quality multiterminal suspended graphene devices.
We introduce a new scheme to realize suspended, multiterminal graphene structures that can be current annealed successfully to obtain uniform, very high quality devices. A key aspect is that the bulky metallic contacts are not connected directly to the part of graphene probed by transport measurements, but only through etched constriction, which prevents the contacts from acting invasively. The device high quality and uniformity is demonstrated by a reproducibly narrow (δn ~ 10(9) cm(-2)) resistance peak around charge neutrality, by carrier mobility values exceeding 10(6) cm(2) V(-1) s(-1), by the observation of integer quantum Hall plateaus starting at 30 mT and of symmetry broken states at about 200 mT, and by the occurrence of a negative multiterminal resistance directly proving the occurrence of ballistic transport. As these multiterminal devices enable measurements that cannot be done in a simpler two-terminal configuration, we anticipate that their use in future studies of graphene-based systems will be particularly relevant.
Départment de Physique de la Matiére Condensée (DPMC) and Group of Applied Physics (GAP), University of Geneva , 24 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland.
Dong-Keun
DK
Ki
Alberto F
AF
Morpurgo