This research deals with the growth mechanisms, structure, and physical properties of incommensurate molecular beam epitaxy (MBE) heteroepitaxy of metal and semiconductor overlayers. The heterostructures will include Ta-Nb and Co-Au superlattices. These overlayers will be deposited on III-V semiconductors as well as sapphire and silicon substrates. Part of the work will address growth processes encountered in migration enhanced epitaxial deposition.