We report on the growth by molecular beam epitaxy of II-VI semiconductor parabolic quantum wells. Cd1−xMnxTe diluted magnetic semiconductor was chosen for constructing these structures because of its extreme sensitivity to the presence of a magnetic field. Photoluminescence excitation spectra revealed several series of energetically equidistant peaks due to interband optical transitions. The energy separation in a given series scales proportionally to the inverse width of the quantum well as expected for a parabolic confining potential. Analysis of the spectra made possible a model-independent determination of the valence band offset in CdTe/Cd1−xMnxTe.

For the iron-boron pair in the p-type silicon two different configurations of the defect are observed: stable and metastable. The reported metastable configuration is the first step in a dissociation process of the stable, i.e. of trigonal symmetry, configuration of the pair. Rate equations for the two-step iron-boron pair dissociation aJlowed us to evaluate the dissociation rates for both configurations of the pair. The driving force for the creation and, then, dissociation of the metastable pair is the minority carrier injection followed by the electron-hole recombination process in the space charge region. A use of the high-resolution Laplace-transform deep level transient spectroscopy allowed us to demonstrate for both of the configurations the influence of the magnetic field on the hole emission.

A detailed light-induced electron-spin-resonance study of iron and chromium impurities in ZnSe is presented. The position of the Fe 2+ /3+ energy level in the band gap of ZnSe is determined. The role of iron and chromium impurities in nonradiative recombination processes in ZnSe is discussed.

A new formula describing the superconducting transition temperature is presented. The electron-phonon coupling constant I and the phonon frequency spectrum parameters of a material are the quantities which define the transition temperature T, of superconductors. A comparison between the experimental and calculated values of T, for metals and alloys confirms the validity of the new formnla presented in this paper.Eine neue Formel, die die Supraleitungsiibergangstemperatur beschreibt, wird vorgestellt. Die Elektronen-Phononen-Kopplungskonstante I und die Parameter des Phononenfrequenzspektrums eines Materials sind GroGen, die die ffbergangstemperatur T, des Supraleiters definieren. Ein Vergleich zwischen den experimentellen und berechneten Werten von T, fur Metalle und Legierungen bestiitigt die Gultigkeit der in dieser Arbeit angegebenen neuen Formel.