Temat: 81.10.Aj - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Correlation Between Crystal Structure, Relative Growth Rates and Evolution of Crystal Surfaces
Autorzy:: Prywer, Jolanta
Tematy:: 81.10.Aj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2035659.pdf Link otwiera się w nowym oknie
Opis:: According to most crystal growth theories, the "as grown" crystal morphology is dominated by the slow-growing faces and the fast-growing faces may "grow out" and not be represented in the final crystal habit. In this paper a brief survey is given of the recently developed correlation between the evolution of both fast- and slow-growing surfaces, their relative growth rates, and the crystallographic structure of crystal. It is shown that even the fast-growing faces may increase their sizes. On the other hand, the slow-growing faces may decrease and, in consequence, disappear from crystal morphology. Such a behaviour of slow- and fast-growing surfaces influences the growth and evolution of both low- and high-index faces.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Czochralski Growth of Decagonal AlCoNi Quasicrystals from Al-rich Solution
Autorzy:: Meisterernst, G.
Bauer, B.
Gille, P.
Tematy:: 61.44.Br
81.10.Aj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1399479.pdf Link otwiera się w nowym oknie
Opis:: Czochralski growth of cm size decagonal AlCoNi single crystals from Al-rich high-temperature solutions is described using native seeds oriented parallel to all symmetrically different crystal directions. Morphological observations allow first hints with respect to anisotropic growth rates. But only classical detachment experiments according to the original idea of Jan Czochralski reveal quantitative results of kinetically limited growth rates. Geometric conditions of wetted plane interfaces as well as aspects of constitutional supercooling affect the detachment experiments. Thus, in only one specific orientation of the decagonal quasicrystal quantitative data for the maximum growth rate could be obtained.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: A Review of the Automation of the Czochralski Crystal Growth Process
Autorzy:: Winkler, J.
Neubert, M.
Rudolph, J.
Tematy:: 81.10.Fq
81.10.Aj
02.30.Yy; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1399420.pdf Link otwiera się w nowym oknie
Opis:: On the occasion of the centennial of the invention of the Czochralski crystal growth process by the Polish scientist Jan Czochralski, a review of selected strategies for the automatic control of this process is given. This review provides a sketch of the fundamental challenges of controlling the Czochralski process and the basic concepts of feedback control. Both early and modern approaches to the control of the Czochralski process are described. The discussion focuses on questions related to feed-forward control, feedback control, and state estimation. The presented methods rely on simple mathematical process models in contrast to the finite element model-based approaches typically used in crystal growth process design and analysis. Such mathematical models motivate both the structure and parameters of the chosen controller. A comprehensive list of references to background literature on this topic completes this survey.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Fabrication, Structural Characterization and Optical Properties of the Flower-Like ZnO Nanowires
Autorzy:: Feng, L.
Liu, A.
Ma, Y.
Liu, M.
Man, B.
Tematy:: 81.07.Bc
81.05.Dz
81.10.Aj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1538755.pdf Link otwiera się w nowym oknie
Opis:: Multipod flower-like zinc oxide (ZnO) nanowires have been successfully synthesized on Si(111) substrates using a pulsed laser deposition prepared Zn film as "self-catalyst" by the simple thermal evaporation oxidation of the metallic zinc powder at 850°C without any other catalysts or additives. The pre-deposited Zn films by pulsed laser deposition on the substrates can promote the formation of the ZnO nuclei effectively. Also it can further advance the growth of the flower-like ZnO nanowires accordingly. X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, Fourier transform infrared spectrum, and photoluminescence were used to analyze the structure, morphology, composition and optical properties of the as-synthesized products. The results demonstrate that the nanowires were single crystalline with hexagonal wurzite structure, grown along the [0001] in the c-axis direction. Room temperature photoluminescence spectrum of the ZnO nanowires shows a nearband-edge ultraviolet emission (peak at ≈ 384 nm) and a deep-level green emission (peak at ≈ 513 nm). In addition, the growth mechanism of the flower-like ZnO nanowires is discussed in detail.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 5.

Tytuł:: Will Czochralski Growth of Sapphire Once Again Prevail?
Autorzy:: Bruni, F.
Liu, C.
Stone-Sundberg, J.
Tematy:: 81.10.Fq
81.10.Aj
61.72.-y; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1399423.pdf Link otwiera się w nowym oknie
Opis:: In the past decade there has been an explosive growth in the consumption of sapphire driven by the demands of the next generation of energy efficient general lighting based on GaN LEDs. This application requires orienting these rhombohedral corundum crystals such that the substrate surface is the c-plane; a basal plane defined using hexagonal axes. Sapphire crystals form a strong facet on the c-plane, and growth in that direction generally results in crystals with high defect densities, particularly dislocations, and low angle grain boundaries. To overcome this drawback, the usual methodology is to grow the crystal in the a-direction and then core drill rods perpendicularly which are then sliced into c-plane substrates. For all crystal growth techniques commonly employed for sapphire, this approach suffers from poor material utilization. Although this has generally been viewed as an acceptable trade-off in the manufacturing process as long as 2" substrates were the dominant market, as substrate diameters have increased towards 150 mm and larger, this compromise is no longer seen as a viable alternative because of the low material utilization and the high energy consumption of the growth process. This has led to a renewed look at the Czochralski process for more efficient c-axis substrate production.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 6.

Tytuł:: Analysis of CMSX-4 single-crystalline turbine blades root by electron and X-ray diffraction methods
Autorzy:: Krawczyk, J.
Zubko, M.
Bogdanowicz, W.
Tondos, A.
Sieniawski, J.
Tematy:: 81.10.Aj
61.72.Ff
61.05.J-; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1058074.pdf Link otwiera się w nowym oknie
Opis:: The root of single-crystalline turbine blade made of CMSX-4 superalloy were studied. The studied blade was produced by the Bridgman technique in industrial ALD furnace at withdrawal rate of 3 mm/min. The samples for investigations were cut from the blade root parallel to the withdrawal direction. Metallographic sections of longitudinal samples planes were prepared for further investigations. The samples were analysed using scanning electron microscopy and the Laue diffraction studies. The crystal orientations in macro-scale were determined by analysis of the Laue pattern and local crystal orientations were studied by electron backscattered diffraction technique. Morphology of dendrites were examined by analysis of scanning electron microscopy macro-images. Study of subgrain structure was performed by X-ray diffraction topography. The sharp parallel contrast bands, visible on the X-ray topograms, were related with dendrite cores, arranged with the same direction. Additionally, the low angle boundaries were formed in certain samples, visible on the topograms as contrast shifts. Step changes of local crystal orientation in certain areas were observed on the electron backscattered diffraction maps. The electron backscattered diffraction crystal orientation maps were related to the misorientation visualized in topograms.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Czochralski Method of Crystal Growth in the Scientific Literature: An Informetric Study
Autorzy:: Sangwal, K.
Tematy:: 81.10.Aj
89.20.-a
89.90.+n; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1399419.pdf Link otwiera się w nowym oknie
Opis:: Bibliometric data on the growth dynamics of papers devoted to the Czochralski method of crystal growth and citations to these papers published in the scientific literature are analyzed using mathematical functions based on progressive nucleation mechanism and power-law approaches. It is shown that the basic concepts of progressive nucleation mechanism originally developed for crystal growth can satisfactorily be applied to explain the citation behavior of papers published on the Czochralski method of crystal growth. It is also found that: (1) cumulative number N(t) of papers and cumulative number L(t) of citations to them at time t are mutually related, and (2) as determined by the plot of the parameter L(t)/$t^2$ against the number Δ N(t) of papers published per year, the citation behavior of papers published on the Czochralski method follows three distinct periods: 1954-1988, 1988-2001 and 2001-2012, which are related to the dependence of the number Δ N(t) of papers published per year on publication time t.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Constitutional Supercooling in Czochralski Growth οf Heavily Doped Silicon Crystals
Autorzy:: Friedrich, J.
Stockmeier, L.
Müller, G.
Tematy:: 81.10.Aj
61.72.S-
61.72.uf
81.10.Fq; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1399427.pdf Link otwiera się w nowym oknie
Opis:: This study analyses the phenomenon of constitutional supercooling, which is one of the major problems in industrial growth of heavily doped ($ > 10^{20} \text{atoms}//cm^3$) silicon crystals by the Czochralski technique. The systematic study is based on theoretical models and experimental data considering the effect of three important dopants (B, P, and As) in dependence of the relevant growth parameters for the Czochralski process. Based on these results, conclusions will be drawn for the stability limits of the Czochralski growth of dislocation-free heavily doped silicon crystals in dependence of the doping species and their concentration.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 9.

Tytuł:: Effect of creep on crystallographic orientation in single crystal superalloy
Autorzy:: Albrecht, R.
Rak, J.
Bogdanowicz, W.
Gancarczyk, K.
Sieniawski, J.
Kubiak, K.
Lelątko, J.
Tematy:: 61.72.Ff
81.10.Aj
61.72.Hh; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1075665.pdf Link otwiera się w nowym oknie
Opis:: The creep-rupture tests were performed on a single crystal rods made of CMSX-4 superalloy obtained at withdrawal rates of 3 and 5 mm/min. After the rupture the microstructure and fracture surface were examined and correlated with X-ray crystal rotation measurements by the Ω-scan method. The conclusions about the crystal lattice rotation during creep test were provided.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Experimental Modelling of Czochralski Melt Flow with a Slow Crystal Dummy Rotation
Autorzy:: Haslavsky, V.
Gelfgat, A.
Kit, E.
Tematy:: 81.10.Aj
47.55.P-
44.27.+g; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1399421.pdf Link otwiera się w nowym oknie
Opis:: This study examines the effect of slow crystal dummy rotation on three-dimensional oscillatory instability and time-dependent supercritical flow states in a Czochralski melt flow experimental model. To enable further comparison with numerical modelling, the experiments are carried out using a 20 cSt silicone oil as an experimental liquid and in a large diameter crucible, which allows one to work in a narrow temperature interval, so that temperature dependence of all the thermophysical properties of the experimental liquid can be neglected. The measurements confirm, partially qualitatively and partially quantitatively, earlier numerical predictions on destabilization ofthe Czochralski convective flow by a slow rotation. A simple power dependence of flow oscillations frequency on the Grashof and rotational Reynolds numbers that fits all the experimental runs was found.
Dostawca treści:: Biblioteka Nauki

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