Embodiments of the present disclosure relate to forming a two-dimensional crystalline dichalcogenide by positioning a substrate in an annealing apparatus. The substrate includes an amorphous film of a transition metal and a chalcogenide. The film is annealed at a temperature from 500° C. to 1200° C. In response to the annealing, a two-dimensional crystalline structure is formed from the film. The two-dimensional crystalline structure is according to a formula MX2, M includes one or more of molybdenum (Mo) or tungsten (W) and X includes one or more of sulfur (S), selenium (Se), or tellurium (Te).