Patent US 5,900,071

A superlattice structure comprising alternating layers of material such as (PbEuTeSe).sub.m and (BiSbn).sub.n where m and n are the number of PbEuTeSe and BiSb monolayers per superlattice period. For one superlattice structure the respective quantum barrier layers may be formed from electrical insulating material and the respective quantum well layers may be formed from semimetal material. For some applications superlattice structures with 10,000 or more periods may be grown. For example, the superlattice structure may comprise alternating layers of (Pb.sub.1-y Eu.sub.y Te.sub.1-z Se.sub.z).sub.m and (Bi.sub.x Sb.sub.1-x).sub.n. According to one embodiment, the superlattice structure may comprise a plurality of layers comprising m layers of (Pb.sub.1-y Eu.sub.y Te.sub.1-z Se.sub.z).sub.m and n layers of Bi.sub.0.9 Sb.sub.0.1, where m and n are preferably between 2 and 20, grown on a BaF.sub.2 substrate with a buffer layer of PbTe separating the substrate and the superlattice structure. For other applications the superlattice structure may be formed from alternating layers of (Pb.sub.1-y Eu.sub.y Te.sub.1-z Se.sub.z).sub.m (quantum barrier layers) and (Pb.sub.1-x Sn.sub.x Te.sub.1-y Se.sub.y).sub.n (quantum well layers)