A method is provided for producing an n-type or p-type epitaxial layer using a doped substrate material. The method includes growing a substrate (12), preferably from a material to which an epitaxial layer can be lattice-matched. The substrate (12) is doped with a predetermined concentration of dopant (14). Preferably, the dopant (14) possesses the ability to rapidly diffuse through a material. An epitaxial layer (16) is grown upon the doped substrate (12). The epitaxial layer (16) and the doped substrate are annealed, thereby causing the dopant (14) to diffuse from the substrate (14) into the epitaxial layer (16).