Klein Tunneling Degradation and Enhanced Fabry-Pérot Interference in Graphene/h-Bn Moiré-Superlattice Devices

Hexagonal boron-nitride (h-BN) provides an ideal substrate for supportinggraphene devices to achieve fascinating transport properties, such as Kleintunneling, electron optics and other novel quantum transport phenomena.However, depositing graphene on h-BN creates moiré superlattices, whoseelectronic properties can be significantly manipulated by controlling thelattice alignment between layers. In this work, the effects of these moiréstructures on the transport properties of graphene are investigated usingatomistic simulations. At large misalignment angles (leading to small moirécells), the transport properties (most remarkably, Klein tunneling) of pristinegraphene devices are conserved. On the other hand, in the nearly aligned cases,the moiré interaction induces stronger effects, significantly affectingelectron transport in graphene. In particular, Klein tunneling is significantlydegraded. In contrast, strong Fabry-Pérot interference (accordingly, strongquantum confinement) effects and non-linear I-V characteristics are observed.P-N interface smoothness engineering is also considered, suggesting as apotential way to improve these transport features in graphene/h-BN devices.