A review is given on the diffusion, solubility and electrical activity of 3d transition metals in silicon. Transition elements (especially, Cr, Mn, Fe, Co, Ni, and Cu) diffuse interstitially and stay in the interstitial site in thermal equilibrium at the diffusion temperature. The parameters of the liquidus curves are identical for the Si:Ti — Si:Ni melts, indicating comparable silicon-metal interaction for all these elements. Only Cr, Mn, and Fe could be identified in undisturbed interstitial sites after quenching, the others precipitated or formed complexes. The 3d elements can be divided into two groups according to the respective enthalpy of formation of the solid solution. The distinction can arise from different charge states of these impurities at the diffusion temperature. For the interstitial 3d atoms remaining after quenching, reliable energy levels are established from the literature and compared with recent calculations. (Read more)

In ZnO crystals, containing both Cu and H(D), we observe characteristic absorption peaks in the near i.r. and three new EPR signals. We explain these results by the formation of impurity complexes consisting of an OH center and one or two Cu ions. (Read more)

At low temperatures, the EPR signal of a Cu2+ center is observed in ZnO single crystals doped both with copper and hydrogen. A clear effect of line narrowing on the copper hfs-lines is observed at T=16K. It is discussed in the model of a Cu-(OH) complex taking into account the thermally induced... (Read more)

The EPR spectra of Cu2+ and V4+ ions have been studied in binary RO---B2O3 glasses (where R = Ba, Sr, Pb and Zn) and in ternary PbO---ZnO---B2O3 glasses. The main results of an EPR study of alkali-borate glasses are briefly reviewed. Three distinct EPR spectra of Cu2+ ions in barium-borate glasses... (Read more)

ZnO polycrystals doped with Li, Cu or Al were prepared by solid-state reactions and their cathodoluminescence (CL) and electron spin resonance (ESR) spectra were measured. A strong yellow emission centered at 2.0 eV was observed for the Al-doped specimen and its intensity was higher than that of... (Read more)

The method of doping trivalent metal ions into a copper-based catalyst for methanol synthesis is effective in modifying the surface structure of the catalyst. The promotion effect and its relation to catalytic activity for hydrogenation of CO to methanol after doping with trivalent metal ions such... (Read more)

Electron paramagnetic resonance (EPR), photoluminescence, and infrared optical absorption have been used to investigate a ZnO crystal before and after a thermal anneal for 1 h in air at 900 °C. The sample was an undoped high quality crystal grown by the chemical vapor transport method. In... (Read more)