Exploring Metal‐Organic Molecular Beam Epitaxy as an Alternative Pathway towards 2D Transition Metal Dichalcogenides WSe₂ and WS₂

A new approach for the growth of vertical 2D van‐der‐Waals heterostructures is reported: Using metal‐organic molecular beam epitaxy (MOMBE), aspects of chemical and physical vapor deposition are combined to grow ultrathin films of WX 2 (X = Se, S) on epitaxial graphene on SiC(0001). Thorough investigation of the films using a variety of spectroscopy, diffraction, and microscopy techniques reveals an island‐like growth of predominantly mono‐ and bilayer regions with crystallite size up to 300 nm, which show a preferred epitaxial alignment with the graphene substrate. Angle‐resolved photoemission reveals a well‐developed band structure of the heterostructure, with the growth process showing minimal effect on the electronic structure of the graphene sheet.