Predominant dislocation types in solar silicon are dissociated into 30°-and 90°-partials with reconstructed cores. Besides shallow 1D-band localized in their strain field and a quasi-2D band at the stacking fault connecting the two partials, the existence of several intrinsic core defects with deep lying levels has been demonstrated by electron spin resonance. The majority of core defects occur in nonequilibrium situations and, with the exception of a small EPRsignal assigned to a reconstruction defect, vanish after careful annealing above 800°C. There is good evidence now that part of deep levels observed in dislocated silicon is associated with impurities, especially with transition metal impurities. Electron-hole-pair recombination at a dislocation mainly runs via its shallow bands and is strongly increased by impurities bound to its core or in the strain field. The concentration of these impurities can be reduced by gettering processes to such a low level that radiative recombination at dislocations yields a luminescence efficiency of 0.1% at room temperature.A quite coherent picture has emerged for metal impurity precipitation in silicon. Early stages of precipitation in defect-free silicon are characterised by kinetically selected metastable defects forming as a result of large chemical M. Seibt ( ) · R. Khalil · V. Kveder · W. Schröter

The early stages of iron precipitation in p-type float-zone silicon have been studied by means of Deep Level Transient Spectroscopy, DLTS, for iron concentrations in the range of 10 14 − 3 × 10 15 cm 3 . A DLTS line showing the signatures of extended localized states is observed. The emission characteristics of the associated defect is very similar to that of the interstitial iron donor. It is concluded that large clusters consisting of interstitial iron atoms give rise to the observed DLTS line.

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The realization of a practical magnesium battery is combined with the development of a high kinetic cathode and compatible electrolyte to facilitate the redox process. For this reason, silver phosphate glasses in the binary system (Fe2O3-AgPO3) are prepared using the conventional quenching method. The glasses were defined in the form [Fe2O3]x[AgPO3](100-x) and the composition with 0  x  40 wt. %. The molar volumes and densities were measured. These glass systems were characterized using XRD, FTIR spectroscopy, UV–Vis-NIR spectrophotometer, electrochemical procedures and impedance spectroscopy. X-ray diffraction revealed that pristine AgPO3 sample was formed in a glassy state, whereas two crystalline phases (AgFeP2O7 and Fe2O3) were formed after the incorporation of Fe2O3 by different concentrations. Bond assignments associated with different functional groups were investigated by an FT-IR spectroscopy. The values of the band gap were decreased with the increase of Fe2O3 content. The effect of grains and grain boundaries in a heterostructure made up of Fe2O3 and AgFeP2O7 crystallites grown in silver phosphate glasses was studied using impedance spectroscopy. The complex impedance, electrical conductivity, and complex electric modulus were measured in terms of frequency and temperature dependency in [Fe2O3]x-[AgPO3](1-x). In the studied glass systems, non-Debye relaxation was observed. Under a variable regime, ac conductivity follows a modified Jonscher's law Arrhenius fitting of multiple relaxation processes in the material yielded activation energy of (0.12 eV–0.271 eV) which support a Maxwell–Wagner relaxation model in the heterostructure glasses at high temperatures and low frequencies. The dc conductivity decreases with iron rate and follows the Arrhenius law with very low activation energy (0.12–0.27 eV. Mg//electrolyte//Glass coin cells are assembled and show an initial discharge capacity of up to ∼564 mAh/g. These materials are attractive for application in modernistic electrochemical devices because of their great compositional and preparation variety which enables tuning the types and techniques of electrical conduction in the material.

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