摘要:

AbstractThe morphology of potassium dichromate (KBC) crystals grown under different conditions by solvent evaporation method is investigated. Observations of the examination of asgrown surfaces and inclusions, and of the realtion between dislocations and inclusions are presented. The results indicate that the change in the morphology of KBC crystals can be associated with the dislocation structure in the crystal.

ISSN:0232-1300    

DOI:10.1002/crat.2170170106

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractAn investigation of the revelation of dislocations in potassium dichromate (KBC) crystals by etching in water, alcohls, and in inorganic acids mixes with acetone and alcohols is carried out. It is observed that several solutions including water, alcohols and organic acids produce disslocation etch pits on various faces of KBC crystals. Observations of twining and dissolution anisotorpy of (001) faces are also presented. Etching of (001) cleavage faces of same crystals in an etchant composed from 1 part HNO3and 3 parts acetone indicates the possible growth of another phase at low temperatures.

ISSN:0232-1300    

DOI:10.1002/crat.2170170107

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractGaP LEC substrates doped with sulphur (ND–NAroughly (3–7) × 1017cm−3) were characterized by transmission electron microscopy. This material was found to contain microdefects such as perfect perismatic dislocation loops, and spherical precipitates. Cross‐sectional TEM investigations perfomed have shown that above all perfect dislocation loops lying directly at the substrate/layer interface are sources for the formation of extended dislocations propagating through the epitaxial layer. Using the methods of selective photoetching and AB‐etching on (110) cleavage faces this phenomenon was obs

ISSN:0232-1300    

DOI:10.1002/crat.2170170108

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractA semiempirical approch for calculation of pAl0.7Ga0.3As‐pGaAs‐nGaAs concentrator solar cell behaviour in a very wide range of operating temperatures (77 K – 490 K) is developed. Experimental values of cell collection efficiency, short circuit current and open circuit voltage are given, while cell fill factor and overall conversion efficiency are calculated. Optimum cell operating conditions are found both for AM 1 and AM 0 radi

ISSN:0232-1300    

DOI:10.1002/crat.2170170109

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractIn heteroepitaxy of ternary compound systems of the type (AxB1–x)1–ΔC1+Δhas to be taken into account the occurrence of complex diffusion phenomena independent on the epitaxial method applied which cannot be considered within a quasi‐binary system AC–BC. Based on the statements of thermodynamics of irreversible processes a model for the calculation of diffusion profiles, regarding the influence of the compound crystal compositionxon the deviation from stoichiometry Δ, is presented. Concentration profiles calculated in accordance to this model show typical maxima and minima. – Tellurium distribution profiles determined on heterostructures of the type (Pb1–xSnx)1–ΔTe1+Δ/PbTe got by electron‐probe microanalysis may be explained qualitatively within the presented model. With the EBIC‐method additional p‐n junctions at the position of the extrema in the tellurium

ISSN:0232-1300    

DOI:10.1002/crat.2170170110

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractOnly after annealing, EBIC investigations on epitaxial layer defects partly gave contrasts. More information on the crystallographic structure of these defects was obtained in subsequent HVEM investigations. Experimental results confirmed the supposition that only the decoration of the crystallographic defects with additional recombination centres (impurity atoms), and not existence of the defects themselves, results in a detectable EBIC contrast. The observed getter efficiency of the various defect types is discussed. This efficiency is growing with increasing lattice distortion.

ISSN:0232-1300    

DOI:10.1002/crat.2170170111

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

Abstract1‐(4‐Nitrobenzylidene)‐pyrazolidone‐(3)‐betaine crystallizes in the orthorhombic space group Pbca with eight molecules per unit cell. The lattice parameters area= 11.025 Å;b= 22.995 Å;c= 7. 677 Å. With X‐ray diffraction data, collected on a automatical four circle diffractometer, the crystal structure was solved by direct methods and refined to anR‐value of 0.047 for 1516 symmetrically independent reflections. The structure determination has been performed to contribute to the explanation of the photochromic behaviour of this special class of a

ISSN:0232-1300    

DOI:10.1002/crat.2170170112

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe variations of the structure and the mechanical properties had been investigated by means of TEM investigations and determination of the microhardness number in theTarange between 0 °C and 180 °C. The main results are the following: – At the starting period of the isothermal ageing an incubation time,tinc, occurs.tincplotted versusTayields two intersecting C curves at about 100 °C. – AtTa= 70 °C the only decomposition product are G.P. zones. – At 70 °C

ISSN:0232-1300    

DOI:10.1002/crat.2170170113

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractBy means solid state track autoradiography has been demonstrated that boron is enriched on grain boundaries of nickel and on texture boundaries of silica glass. This result has been proved on nickel by SIMA and on silica glass by luminescence autoradiography.

ISSN:0232-1300    

DOI:10.1002/crat.2170170114

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe influence of the lithium impurity on the formation and the stability of electronic colour centres is studied in NaF crystals. It is found that F‐ and M‐absorption bands are somewhat displaced to the long wavelengthes when doping with lithium owing to the overlapping with FA‐ and MA‐absorption bands. It is shown that the lithium impurity is stabilising one for the charged M‐centres though their accumulation in the doped crystals occurs slower. The activation energy is determined for the thermal destruction of M+‐ centres. Thermal destruction of M+‐centres assumed to be resulting from the anion va

ISSN:0232-1300    

DOI:10.1002/crat.2170170115

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY