No abstract available

[en] This paper reports on investigations into the crystallography of radiation-induced phase conversions. Poly-crystalline, tetragonal BaTiO₃, mono-clinic CaTiO₃, cubic SrTiO₃ and cubic stabilised BaTiO₃ were irradiated under various conditions in the Rossendorf research reactor. The experiments indicated that several types of defect occurred side by side of which oxygen defects constituted the largest proportion

[en] Short note

[en] High-temperature in-situ Hall coefficient and conductivity measurements are used for the investigation of the composition limits of stability of PbTe, which are found to be much broader than obtained by measurements on tempered and quenched samples. Investigations of isochronic time-temperature relations make possible the calculation of the formation and motion energies of the main native defects in the p-type and the n-type side of the stability region, which are assumed to be a Pb vacancy, V'_Pb, and a Pb interstitial ion, Pb_i, respectively. E_Pbi^f = (0.09 ± 0.005) eV and E_Pbi^m = (0.18 ± 0.05) eV are much lower than referred until now in the literature. E_VPb^f = (0.32 ± 0.05) eV and E_VPb^m = (0.62 ± 0.05) eV nearly agree with data obtained by other authors. The diffusion coefficient of Pb in Te-rich PbTe is evaluated to D₀ = 1.1·10^-9·exp(-0.62 eV/kT) cm²/s. (author)

[en] The incorporation behaviour and the electrical activity of Tl in PbTe were investigated by the measurement of lattice constants, carrier concentration, and Tl concentration. The lattice constant a decreases with increasing carrier concentration. The decrease of lattice constant with growing Tl concentration can be explained on the basis of complexes formed by the dopants and point defects (vacancies)

[en] In order to investigate the influence of crystal imperfections, especially grain boundaries and dislocations on the diffusion behaviour of mercury in bulk (Hg,Cd)Te some tracer diffusion experiments of ²⁰³Hg into p-type Hg_0.8Cd_0.2Te were performed. Autoradiographic, electron beam induced current, and thermoprobe voltage measurements make clear that diffusion of ²⁰³Hg into p-type (Hg,Cd)Te is considerably increased by large-angle grain boundaries (GB), while the effect of small-angle GB and dislocations on diffusion seems to be negligible

[en] The X-ray diffraction rocking curve analysis has been employed for the measurement of crystallite sizes of (Pb, Sn)Te films for different thickness, epitaxially grown on KCl cleavage faces by the hot-wall technique. The size of the coherently scattering regions parallel to the reflecting planes did not depend on film thickness and agreed with the mean distance of nuclei just before coalescence, investigated by means of replica electron microscopy. The results are consistent with a model of stalk-like growth of crystallites in film growth direction. (author)

[en] The microhardness of Hg_1-xCd_xTe and Hg_1-xZn_xTe has been measured on monocrystalline samples of Bridgman and travelling heater method crystals as a function of compositon x by means of Vickers indentation measurements at room temperature. The curves show maxima of about 830 MPa at x ∼ 0.75 for Hg_1-xCd_xTe and of about 1700 MPa in the range 0.65 ≤ x ≤ 0.8 for Hg_1-xZn_xTe. The hardness-relaxation behaviour has been measured on {111} samples in order to obtain the internal stress level and to investigate the stress-relaxation behaviour. The theoretical hardening rate dH/d(x)^0.5 was compared with experimental values. (author)

[en] Differently treated PbTe surfaces have been investigated by means of reflection high energy electron diffraction (RHEED) and Rutherford backscattering (RBS). It has been shown that chemical lap polishing followed by heat treatment is the best method to fulfil the requirements of the following epitaxy process concerning the absence of contaminations, the high structural surface perfection, and the flatness of the substrates. The influence of heat treatment on structural perfection and chemical composition in the surface region has been investigated to determine the optimal conditions for the tempering step before epitaxy. (author)

No abstract available