Understanding the Electrical Impact of Edge Contacts in Few-Layer Graphene

Two-dimensional layered materials including graphene and transition metal dichalcogenides are identified as promising candidates for various electronic and optoelectronic applications. Due to the weak coupling between individual layers, large contact resistances are frequently found and dominate the performance of layered material systems. In this paper, we employ few-layer graphene as an example to demonstrate a self-aligned edge-contacting scheme for layered material systems. Bypassing the tunneling resistances associated with the weak coupling between layers, lower contact resistances are achieved compared to conventional devices with top contacts. A resistor network model taking into account the gate field screening in the layer stack and all associated resistances is used to quantitatively explain the improvement and compare the current transport in both top-contacted and edge-contacted devices.