Electronic transport properties of graphene channel with metal electrodes or insulating substrates in 10nm-scale devices

摘要

We have studied the electronic transport properties of armchair graphene nanoribbons (AGNRs) bridged between two metal electrodes or supported on insulating substrates in 10nm-scale devices using the first-principles calculations. The two metal species of Ti and Au are examined as metal electrodes and are compared. The current densities through the AGNR-Ti contact are about 10 times greater than those through the AGNR-Au contact, even though the AGNR width reaches 12nm. For the insulating substrates, we have investigated the dependence of the channel length on the transport properties using models with two channel lengths of 15.1 and 9.91 nm. Regardless of the channel length, the on/off current ratio is 105 for the AGNRs on an O-terminated surface. This ratio is consistent with the recent experiments and is less by factors of 10~(16) for the 15.1 nm channel length and 108 for the 9.91 nm channel length compared to the freestanding AGNR.