Two-Dimensional Wse2/Mose2 Heterostructures Grown By Molecular-Beam Epitaxy

Large-area two-dimensional MoSe2/WSe2 and WSe2/MoSe2 heterostructures have been successfully fabricated using molecular-beam epitaxy. Highly oriented heterostructures are composed of alternately stacked epitaxial MoSe2 and WSe2 monolayers (MLs) on Se-treated GaAs(111)B substrates with nearly stoichiometric compositions. The MoSe2 and WSe2 MLs are weakly bonded together and show either the stable C7 or the T stacking configuration, irrespective of the stacking order. We further demonstrate that the four-layered heterostructures are realized by the successive growth of MoSe2 and WSe2 MLs.