Revealing the interlayer orientations for bilayer graphene grown on hexagonal boron nitride by c-AFM measurement

Abstract

Owing to its excellent properties in optical and electronic applications, twisted bilayer graphene (TBG) has attracted extensive research attention. As an encapsulation layer, hexagonal boron nitride (h-BN) is indispensable for fabricating TBG devices. Because h-BN and graphene exhibit similar lattice structures, TBG on h-BN exhibits periodic moiré patterns, which enable interlayer orientations to be revealed for bilayer graphene on h-BN. Herein, we used two-step chemical vapor deposition to synthesize TBG exhibiting multiple twist angles on h-BN. Conductive atomic force microscopy measurements revealed that the conductivity distribution was different for the graphene/h-BN and TBG moiré patterns. Using the characteristics of the moiré patterns formed by these layers, h-BN and graphene interlayer orientations were precisely determined. This provides a feasible method for investigating the turbostratic arrangement of few-layer van der Waals heterostructures.