Lateral Composite Structures of Graphene/Graphane/Graphone: Electronic Confinement, Heterostructures with Tunable Band Alignment, and Magnetic State

Graphene can be hydrogenated fully on both sides and also semihydrogenated on one side to constitute graphane and graphone, respectively. While both are wide band gap semiconductors, graphone also acquires a magnetic ground state originating from unpaired π-bonds. We predict that lateral composite structures/heterostructures can be constructed by the patterned dehydrogenation of graphane or graphone with commensurate interfaces, which display diverse physical properties depending on their constituents, interface geometry, and size. When constructed by consecutive graphane and graphene strips of very narrow width, they can attain exclusive electronic and magnetic properties in 2D, which are different from those of both parent materials. However, periodic and commensurate semiconductor–semiconductor heterostructures with straddling band alignment and tunable band gaps can form, if the widths of strips with the armchair interface are wide enough to entail confinements of electronic states and hence to change the dimensionality of the system from 2D to 1D. Depending on the type of zigzag interface, periodic heterostructures attain spin polarized straddling band alignments. Composite structures patterned on graphone can form magnetic semiconductor–semiconductor heterostructures, which have different staggered band alignments for different spin polarization. Specifically, under the in-plane electric field, a single heterostructure constructed on zigzag nanoribbons can change its magnetic state and start to operate as a magnetic diode for one spin direction. All of these composite structures, which allow electronic confinement followed by a change of dimensionality, offer various quantum structures and functionalities with potential applications in spintronics