Electronic Structure And Transport Properties Of Graphene/h-BN Heterostructure

Graphene/hexagonal boron nitride(h-BN)heterostructure is one of the typical van der Waals heterostructure,with a variety of excellent performance,and has potential application value in future of nanoelectronics.Therefore,studying the graphene/h-BN heterostructure is of great significant for the design of new devices.However,many of the electronic and transport properties behind it have not been better understood.In this thesis,we will systematically study the band structure and transport properties of latticematched zigzag-edged graphene/h-BN heterostructure under the electric field,local potentials and magnetic field from the following points using tight-binding model and Green function method,and got some meaningful conclusions.Firstly,we investigate the change of the band gap of graphene/h-BN nanoribbons under electric field and the band structure and transport properties under local potentials.By separately applying the electric field on the graphene layer,the boron nitride layer,and the graphene and boron nitride layers of the system,we found that the variation law of the band gap is different within a certain electric field intensity range.By applying different local potentials,the band structure and transport properties can be significantly changed.A method to individually manipulate the edge states by local potentials is also proposed,including shifts and other deformations of edge bands.At the same time,we find that the two-terminal conductance of graphene and h-BN layer is quantized but the interlayer conductance is non-quantized due to band mixing.Secondly,we investigate band structure and transport properties of graphene/h-BN heterostructure under both perpendicular magnetic field and local potentials.By applying a perpendicular magnetic field,we find that Landau level spectrum are similar to that of monolayer graphene in low energy region,while the Landau level spectrum are similar to that of monolayer h-BN in high energy region.Under both perpendicular magnetic field and local potentials,the interface state will appear.Interestingly,the interlayer conductance exhibits the plateaus-like behavior in the vicinity of zero energy.In summary,we mainly study band structure and transport properties of zigzagedged graphene/h-BN nanoribbons under the electric field,local potentials and perpendicular magnetic field,and these results are expected to be useful for future applications of electronic devices.