ABSTRACT
Epitaxial metallic films grown on semiconductor substrates are most attractive when they consist of materials which are thermodynamically stable with respect to the underlying semiconductor. This allows, under the proper growth conditions, the overgrowth of epitaxial semiconductor layers, thus forming monocrystalline semiconductor/metal/semiconductor heterostructures with exciting physics and device possibilities. This paper discusses our recent work in the growth of stable and epitaxial metallic layers which meet these stringent criteria on III-V semiconductors. Work on layers sharing either a common group III element with the III-V, such as AlAs/NiAl/AlAs or a common group V, such as GaAs/ErAs/GaAs, will be presented. The potential applications are further enhanced when the metallic films display an added functionality such as ferromagnetic behavior, demonstrated in epitaxial MnAl/AlAs/GaAs heterostructures. Examples of new directions for III-V structures made possible by such heteroepitaxy, are discussed. They include tailoring of Schottky barrier heights, integration of metallic quantum wells into high-speed three-terminal devices, and integration of magnetic storage functionality with III-V electronics.
