Lateral heterojunctions within monolayer h-BN/graphene: a first-principles study

Abstract

Very recently, the lateral heterojunctions of hexagonal boron nitride (h-BN)/graphene were experimentally realized for the time. To study the related properties of such heterojunctions with the purpose of searching for new avenues to realize controllable and tunable 2D electric devices, in the present work we perform a systematic theoretical investigation on a series of structures constructed by zigzag h-BN and zigzag graphene monolayers based on first-principles calculations. Our results demonstrate that the electronic structures as well as the magnetic properties of the hybridized monolayers can be modified efficiently. Furthermore, the character transition from insulator to metal can also be realized by the proposed approaches of adjusting the numbers or the ratios of the zigzag h-BN and zigzag graphene. Interestingly, the investigation of the strain dependence of the electronic properties in the selected structure reveals that the external strain applied along the Y-axis plays a decisive role in the bandgap engineering. Moreover, the calculated effective masses give a reasonable physical representation of the carrier transport properties. Our results show that the mobility direction of the charge carriers is parallel to the interface. These predictions provide new potential strategies for tuning electronic properties and will allow new device functionalities, such as in-plane transistors, diodes and spintronic devices, to be integrated within a single thin layer.