Field Effect in Graphene-Based van der Waals Heterostructures: Stacking Sequence Matters.

Stradi, Daniele; Papior, Nick R; Hansen, Ole; Brandbyge, Mads · Nano Lett · 2017

basic_science · Level V

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Abstract

Stacked van der Waals (vdW) heterostructures where semiconducting two-dimensional (2D) materials are contacted by overlaid graphene electrodes enable atomically thin, flexible electronics. We use first-principles quantum transport simulations of graphene-contacted MoS<sub>2</sub> devices to show how the transistor effect critically depends on the stacking configuration relative to the gate electrode. We can trace this behavior to the stacking-dependent response of the contact region to the capacitive electric field induced by the gate. The contact resistance is a central parameter and our observation establishes an important design rule for ultrathin devices based on 2D atomic crystals.