Fundamental issues in heteroepitaxy---A Department of Energy, Council on Materials Science Panel Report

During the past decade, nonequilibrium techniques have been developed for the growth of epitaxial semiconductors, insulators, and metals which have led to new classes of artificially structured materials. Structures can now be grown which present the materials scientist with systems that exhibit new properties and demonstrate new physical concepts. For example, quantum-well structures with molecular dimensions give rise to new phenomena resulting from quantum mechanical effects. Layered structures with periodicity of a few atomic layers result in coherent behavior for long-range interactions such as magnetism in metallic systems. Metastable structures can be generated which possess important properties not present in equilibrium systems. Studies of these materials are leading to significant advances in our basic understanding of the physics of materials as well as to important new technologies. Despite the rate of progress and the large number of laboratories throughout the world with active programs in various aspects of epitaxial growth, our current understanding of the processes which control growth at a fundamental, atomic level is remarkably primitive. Much of the work to date has been driven by the motivation to produce high quality materials for high performance electronic devices. As a result, most of the effort in epitaxial materials hasmore » concentrated on semiconductors, particularly GaAs and related compounds.« less