Synthesis of designed W-WSe₂ heterostructures from superlattice reactants

A nanocomposite consisting of alternating, orientated, crystalline layers of tungsten and tungsten diselenide was prepared using a designed elemental superlattice as the initial reactant. In binary tungsten-selenium multilayers, tungsten diselenide was observed to interfacially nucleate upon deposition and grow preferentially along the interface. This information was used to design a multilayer reactant containing a thick tungsten layer in addition to thin tungsten and selenium layers in the repeating unit. The evolution of the structure of the superlattice reactant as a function of annealing temperature was followed using both low- and high-angle diffraction. The diffraction data confirmed the formation of a superlattice or nanostructured composite consisting of alternating layers of tungsten and tungsten diselenide containing crystallites limited in c-axis domain size by the layer repeat.