A method of forming an epitaxial film on a substrate includes growing an initial layer of a film on a substrate at a temperature Tgrowth, said initial layer having a thickness h and annealing the initial layer of the film at a temperature Tanneal, thereby relaxing the initial layer, wherein said thickness h of the initial layer of the film is greater than a critical thickness hc. The method further includes growing additional layers of the epitaxial film on the initial layer subsequent to annealing. In some embodiments, the method further includes growing a layer of the film that includes at least one amorphous island.