Zur plastischen Verformung von Antimoneinkristallen im Druckversuch bei Raumtemperatur

The plastic deformation of antimony single crystals dynamically tested in compression at room temperature has been investigated. As macroscopic deformation mechanisms twinning, dislocation slip, and kinking have been observed. The critical resolved shear stress for basal slip and twinning was measured and the orientation dependence of the deformation mode was explained. It is shown that basal slip dominates compared to rhombohedral slip.     

Erfahrungen mit der Funkenerosiven Bearbeitung von Antimoneinkristallen

This paper discribes a simple equipment for the electric spark discharge machining of single crystals, especially employed for antimony. It is possible to produce specimens of various shapes, sizes, and different crystallographic orientations. The spark-cut crystals of antimony are investigated with regard to the roughness of the surface and the extent of the plastically deformed range (deformation twinnings and dislocations) in dependence upon the maximum storaged energy of the capacitor. Formation and distribution of the deformation structures are explained on the basic of the resolved shear stress (Schmid-factor) in the glide and twinning system respectively.     

Zur Lamellenstruktur von Silizium-Kristallnadeln

Observations are reported on the lamellar structure of silicon needles with different forms of cross-section.     

Zur Bildung von Adsorptionsmischkristallen

By investigating the systems KCl-H₂O-impurity and NH₄Cl-H₂O-impurity the knowledge of the formation of Adsorptionsmischkristallen could be extended. Some specific properties of complex mixed systems are stated.     

Zur Lumineszenz von Zinksiliziumphosphid

Results of cathodoluminescene measurements of ZnSiP₂-single crystals grown by different techniques are reported. The luminescence excited in the various samples showed considerable differences in intensity and spectral position. These differences are apparently caused by the irregular incorporation of recombination centres in the present stage of crystal growth. Samples grown by “vapour phase technique with ZnCl₂” and by “spontaneous crystallisation from Sn or zn melt” showed line spectra typical for the special method of crystal growing. This relation between a typical line spectrum and the method of crystal growing chosen is attributed to the participation of intrinsic defects in the recombination processes. The detection of doping elements by means of luminescence measurements is discussed for ZnSiP₂ crystals doped by adding Te, Se, Ga. or In to the Zn melt.     

Zur Struktur von organischen Mischkristallschichten

The structure of organic mixed crystal films is investigated by means of a appropriated model - copper phthalocyanine/vanadyl phthalocyanine. These films are polycrystalline and contain mixed crystal grains, the size being smaller than that which can be detected by X-ray methods. By infrared spectroscopy and scanning electron microscopy or after recrystallisation by texture goniometer investigations the orientations of microcrystals on the substrate was obtained.     

Zur Realstruktur von hochdotierten Galliumarsenid-Einkristallen

Investigations of defect structure (etching, cathodoluminescence et al.) on highly doped GaAs single crystals, grown by liquid encapsulation technique, are reported. The correlation of appearance of cellular structure and growth parameters are discussed.     

Zur Charakterisierung von hochdotierten GaAs-Einkristallen

Investigations of structure defects in high Sn doped GaAs monocrystals grown by the liquid encapsulation technique were carried out using etch techniques, infrared microscopy and X-ray topography. Specific defects in connection with inhomogeneous insertion of the dopand caused by constitutional supercooling and cellular growth could be observed. – Described are the geometry, the distribution and the cause of the occurrence of these defects. The effect of these latter on the luminescense is investigated.     

Zur Textur von Aufdampfschichten des Kupferphthalocyanins

Vapour deposited films of α-CuPc with a thickness of some μm and β-CuPc films, thermically obtained from the α-films were investigated by means of X-ray diffraction and electron microscopy. With the α-films a brush-like structure with an angle of about 20° between the b-axis and the normal of the substrate was derived from the results of X-ray texture studies. For a small part of each sample, deposited obviously at first as a thin film with 0,1 μm or less in thickness, an orientation of the b-axis parallel to the plane of the substrate was found. The structure of the α-films can be preserved in a careful α-β-transformation, but is lost if the transformation is carried out rapidly. Electron microscopic studies confirm the results of the X-ray investigations.     

Zur Abbildung von Isolierschichtdefekten im Elektronenspiegelmikroskop

Following the investigations on the imaging behaviour of homogeneous dielectric layers considerations on the possibilities of imaging simple layer inhomogeneities are discussed. These considerations imply a contrast amplification by charging phenomena. By definite variation of the substrate potential a distinction between geometrical layer defects (protrusions, indentations, holes) and electrical inhomogeneities of the insulating layer (regions of increased and decreased conductivity, resp.) is possible as shown by the experimental investigations. Criterions for distinguishing different cases can be given. The sensitivity for detecting inhomogeneities in non-covered dielectric layers is higher than in the case of those being covered with a conductive layer.     

Zur Kristallisation von Melilith aus der Glasphase

A relation between temperature of crystallization and crystal habit produced by crystallization from melilith glass is established and evaluated quantitatively. A nonsteady state induction period depending on temperature was observed basing on ROY 's theory of glass structure. The linear crystal growth rate depending on temperature is reported, and the resulting influence of adsorption rate and diffusion on the temperature depending habit of crystals discussed.     

Zur Beeinflussung von Tracht und Habitus von Harnstoffkristallen (I)

It is shown that during crystallization urea forms mixed crystals, adsorption mixed crystals and epitaxial growth from aqueous solutions with NH₄Cl. The extent of the formation of mixed crystals is fixed by the composition of the solution. The urea NH₄Cl mixed crystals have the effect of morphological transformers on tracht and habit of the crystallized urea, so that advantages in technical application result concerning properties of transport and storage.     

Zur Heteroepitaxie von AIBIIIC2VI-Verbindungen – Interpretation von RHEED-Diagrammen

Semiconductors of the A^IB^IIIC₂^VI type, crystallizing in the chalcopyrite structure, grow epitaxially with their {112}-planes on monocrystalline substrates with a three-fold symmetry of faces. It is shown that application of the RHEED technique permits definitively to decide what kind of epitaxial overgrowth takes place, supposing the atomic scattering factors of the I and III atoms are sufficiently different and/or the c/a axis ratio differs markedly from 2. CuInSe₂/GaAs and CuGaSe₂/GaAs show one-dimensional epitaxy     

Zur Kristallographie von Doppelsalzen aus Calciumsulfat und Natriumsulfat

In the course of investigating a special slurry problem in the Na₂SO₄ production metastable double salts of calcium sulphate and sodium sulphate were detected (Emons, Stegmann). In this paper it is reported on the properties of these compounds and their decomposition products, determined by microscopic, X-ray, thermoanalytic, and IR-spectroscopic methods.     

Zur Diffusion von Hf und Ti in Ni

The diffusion coefficients and solubilities of Hf in Ni were measured with the electronprobe at sandwich samples. The temperature dependence of the diffusion coefficients of Hf in Ti was compared with the corresponding values of the system Ti in Ni. In both systems was found a good accordance with the Arrhenius relation within four orders of magnitude. The solubility of Hf in Ni is found to be nearly by the factor 2 larger than the values known from earlier papers.     

Zur dynamischen Untersuchung elastischer und elektromechanischer Eigenschaften von Kristallen

For the determination of elastic and piezoelectric coefficients as well as of the mechanical quality factor the piezoelectric resonator has proved a most simple and exact method. In this paper some possibilities for increasing the accuracy of this method and its application on weak piezoelectric crystals as well as for the determination of higher order elastic coefficients are shown. These procedures can also be used for dynamic measurements on electrostrictive materials (electrostrictive resonator).