Sipatov O. Epitaxial superlattices and quantum structures from lead, tin, europium and itterbium chalcogenides

Object of studies - the effects and physical phenomena which are connected with low-dimention transition of semiconductor system. Goal of studies - the establishment of the rules and effects wich are connected with low-dimention transition of chalcogenide semiconductor superlattices with lattice misfit of there layers. Study methods. The sumples was made by thermal (electron-beam or resistive from tungsten boats) evaporation and vacuum condensation onto crystal substrates. The layer thickness and condensation rate were monitored by calibrated quartz resonator. The electron microscopy, X-ray and neutron diffractions are used for structural investigations. The complex of modern low-temperature methods for measurement of the optical, electrical and magnetic characteristics is used for physical properties investigations.Theoretical and practical resalts and novelty. The multilayer chalcogenide semiconductor films with large layer lattice misfit (0,5 - 13%) give us the possibility not only to extend thenumber of superlattice materials, but open the new opportunity to create one- two- and three- dimensional superlattice nanostructures with new properties and effects. The superconductivity was discovered for the first time in two-dimensional (dislocational) superlattices. The presence of periodic networks of misfit dislocations at interfaces is directly responsible for the superconductivity (the absence of dislocations leads to the absence of superconductivity). The luminescence spectra from quantum dots were discovered for the first time in three-dimensional PbSe-PbS superlattices. The dots were made by structure modulations from periodic misfit dislocations in the plane of multilayers and composition modulations in the orthogonal direction. The resonance tunneling of electrons via ferromagnetic EuS barriers was found for one-dimensional (compositional) superlattices. The antiferromagnetic interlayer coupling of magnetic EuS layers via non-magnetic PbS and YbSe spacers was found for the first time in semiconductor superlattices. Such coupling was observed for unusual wide range of spacer thicknesses for narrow-gap PbS semiconductor (from 0,4 nm to 40 nm) and wide-gap YbSe (from 1 nm to 3 nm). Application fields: semiconductor physics, optoelectronics, spintronics.