摘要:

AbstractCalculations of layer thicknesses and composition profiles in Hg1−xCdxTe layers on CdTe substrates for the growth from Te‐rich melts have been carried out for liquidus temperatures of 460 °C, 480 °C, and 500 °C. This has been made on the basis of the multicomponent diffusion model of SMALLand GHEZand the solid‐liquid phase relation of BRICE. It could be shown that growth velocity increases only slightly with rising liquidus temperature. On the other hand, the interdiffusion velocity of Hg and Cd in the solid increases remarkably at a higher temperature. Therefore, to get layers with a constantx‐value a higher supersaturation of the melt is necessary. Thex‐value decreases with rising supercooling by about 0.003 K−1. To demonstrate the thermodynamically and kinetically advantageous properties of CdTe as substrate material, comparative calculations for a “hypothetical” HgTe substrate

ISSN:0232-1300    

DOI:10.1002/crat.2170260107

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractWe present a new device for the measurement of the metastable zone width and related parameters. The salting‐out is detected by using simultaneously seven different methods: a) visual detection, b) intensity of the transmitted laser beam, c) noise associated to (b), d) intensity of the reflected laser beam, e) noise associated to (d), f) conductivity, and g) pH. Full computerization permits an easy and quick take of data on the evolution of the nucleation and crystal growth processes. The use of this apparatus shows that the waiting time for the growth component of the induction time is minimized for the method using the noise associated to the reflected light as the recorded parameter. This comparative study shows that the maximum undercooling and maximum allowable supersaturation values obtained by the different tested methods present significant differences between each other. Meanwhile, we propose that the tabulated values of such parameters should specify the experimental way followed for the obtainment of reliable dat

ISSN:0232-1300    

DOI:10.1002/crat.2170260108

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractSurface topography and macromorphology of potassium bichromate crystals grown from unstirred aqueous solution depend on diffusion and convection. Micromorphology of as‐grown surfaces is a source of quantitative data on the local values of the degree of supersaturation σ at various parts of crystals. Micromorphology and values of growth velocities of faces, differently located in space with respect to the gravitational force show that upper parts of the crystals grow at about 5–25% lower values of σ than the lower ones. The cause of convection changes of size and number of faces is the characteristic distribution of supersaturation around the crystal induced by movement of the sol

ISSN:0232-1300    

DOI:10.1002/crat.2170260109

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThe structure and the depth distribution of radiation damage caused by erbium implantation (Ei= 100 keV,D= 5 × 1015cm−2,Ti= LNT) in 〈111〉 cadmium telluride have been investigated by means of planar‐view and cross‐sectional TEM techniques. It is found that the implantation disturbes the CdTe target up to the depth well‐beyond the calculated projected range (that is ≳ × 5Rp). The resulting damage structure consists of well‐defined defects: precipitates, stacking faults, dislocation loops, and dislocation networks, which appear to be segregated with depth forming a sequence of homogeneously faulted zones. This characteristical and deep damage is suggested to be formed on dynamic annealing in response to internal stresses (caused by lattice parameter mismatch) which are high enough to produce plastic relaxation with dislocation generation and slip.This study is aimed at describing the ion‐implantation‐induced damage in single crystal cadmium telluride caused by Er+ions by means of transmissio

ISSN:0232-1300    

DOI:10.1002/crat.2170260110

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractCharacterization of growth defects by X‐ray topography of Guanidine aluminium sulfate hexahydrate crystals allows to set a close correlation between ferroelectric domain and growth sector patterns. The crystalline quality of prismatic sectors is much better than that of basal sector

ISSN:0232-1300    

DOI:10.1002/crat.2170260111

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170260112

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThe absorption in F‐band of NaCl single crystals after X‐ray irradiation and later excited with laser light is studied. Similar investigations have been carried out when these crystals are subjected to high AC electric fields prior to X‐ray irradiation and also at elevated temperatures. Effect of laser excitation on γ‐ray irradiated samples is studied. An attempt is made to understand the results in terms of the disorder that sets in in these

ISSN:0232-1300    

DOI:10.1002/crat.2170260113

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractConductivity, Hall‐effect measurements were performed on δ‐phase In2Se3single crystals, grown by the Bridgman method over the temperature range 150–428 K, in the directions perpendicular and parallel to thec‐axis. The anisotropy of the electrical conductivity and of the Hall coefficient of n‐type In2Se3had been investigated. The values of the Hall coefficient and electrical conductivity at room temperature spreads from an order ofRH11= 1.36 × 104cm3/coul, σ11= 4.138 × 10−3Ω−1cm−1andRH= 66.55 × 104cm3/coul, σ = 0.799 × 10−3Ω−1cm−1for parallel and perpendicular toc‐axis, respectively. The temperature dependence of Hall mobility and carrie

ISSN:0232-1300    

DOI:10.1002/crat.2170260114

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170260115

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThe quality of the fit between the precipitates occurring in Al–Zn alloys and the matrix of the Al host is considered taking into account the positions of the atoms in the lattice planes forming the possible faces of the precipitates and the neighboured lattice planes of the matrix. The quality of the fit depends on the number of (pseudo‐)coincidence sites of both planes, the density of Al atoms in the matrix plane and the misfit in the spacings of the atoms in the adjoining planes in consideration. The effect of the misfit is taken into account by means of two different models. Based upon the obtained results many of the experimentally observed features about the preferred shapes and orientations of the faces of the growing precipitates can be explained. It turned out that in both of the applied models most probably the effect of the density of the coincidence sites on the interfacial energy is underestima

ISSN:0232-1300    

DOI:10.1002/crat.2170260116

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY