Realization of larger band gap opening of graphene and type-I band alignment with BN intercalation layer in graphene/MX2 heterojunctions

Band gap engineering of graphene has been intensively studied, but it is still difficult to be realized effectively in practice, which limits its applications in optoelectronics. Here, by using first-principles methods, we predicate that the band gap of graphene can be obviously enlarged up to 0.83 eV and type-I band alignment is also realized in the graphene/BN/MX2 (M = Mo, W; X = S, Se) heterotrilayers when the interlayer distance is compressed. Moreover, the electrons and holes can be confined inside the gap opened graphene layer, and the staggered band alignment can be formed under the presence of electric field as well as the vertical pressure in the graphene/BN/MX2 heterotrilayers. Our results may pay an effective route to tune the gap of graphene and broaden its applications in optoelectronic fields.