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1. Metal–alloy induced crystallization of amorphous silicon.

Author

Sanwald, Philipp, Wang, Zumin, and Mittemeijer, Eric Jan

Subjects
AMORPHOUS silicon, SEMICONDUCTOR thin films, CRYSTALLIZATION, SEMICONDUCTORS, ALUMINUM-zinc alloys, SEMICONDUCTOR materials, SILICON alloys
Abstract

A comprehensive investigation of metal–alloy induced crystallization (MAIC) of amorphous silicon (a-Si) is presented. The crystallization processes in three microstructurally principally different, representative types of metal(-alloy)/a-Si systems, Alx(Ge1−x)/a-Si, AgxAl1−x/a-Si, and AlxZn1−x/a-Si, have been monitored by in situ heating x-ray diffraction (XRD) from 25 °C up to 475 °C, until crystallization of a-Si was completed. The obtained experimental results have been systematically compared to predictions obtained by applications of thermodynamic models based on calculations of interface and crystallization energies for the determination of so-called critical thicknesses and initial crystallization temperatures. From the investigation of the MAIC processes in the metal–alloy/a-Si systems, it has been demonstrated that the crystallization temperature and the crystallization kinetics can be well tailored and optimized by controlling the composition and microstructure of the metal alloys. This research, on the one hand, exposes the fundamental, principal role of interface thermodynamics on the crystallization processes and, on the other hand, opens new possibilities for the growth of technologically important, pure, crystalline semiconductor thin films at very low temperatures, as compared to the crystallization temperature of isolated, bulk semiconductor materials. [ABSTRACT FROM AUTHOR]

Published
2020
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16. Contributor contact details

Author

Pereloma, Elena, primary, Edmonds, David, additional, Hackenberg, Robert E., additional, Ågren, John, additional, Hillert, M., additional, van der Zwaag, Sybrand, additional, Enomoto, Masato, additional, Strangwood, M., additional, Kral, Milo V., additional, Embury, David, additional, Liu, Yongchang, additional, Mittemeijer, Eric Jan, additional, Singh, S.B., additional, Furuhara, Tadashi, additional, Caballero, Francisca G., additional, Borgenstam, Annika, additional, Hillert, Mats, additional, Sietsma, Jilt, additional, Hodgson, P., additional, Beladi, H., additional, Zhang, Yudong, additional, Esling, Claude, additional, Meshkov, Yu.Ya., additional, and Pereloma, E.V., additional

Published
2012
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17. Kinetics of crystallization of amorphous Mg80Cu10Y10

Author

Nitsche, Heiko, Stanislowski, Michael, Sommer, Ferdinand, and Mittemeijer, Eric Jan

Abstract

The crystallization kinetics of an amorphous magnesium-rich Mg80Cu10Y10alloy has been determined by isothermal and isochronal differential scanning calorimetry combined with ex-situ X-ray diffraction for phase analysis. Microstructure analysis has been performed by means of transmission electron microscopy. Complete crystallization of Mg80Cu10Y10has been found to take place in three steps. Independent of the type of annealing, during the first crystallization process at around 430 K particles of several phases are formed with an equiaxed morphology. Kinetic analysis applying a new analytical model demonstrated that Avrami nucleation and volume-diffusion-controlled growth are the operating nucleation and growth modes. The effect of yttrium on the transformation kinetics has been discussed.

Published
2022
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18. Phase transformations of iron nitrides at low temperatures (< 700 K) – application of mechanical mixtures of powders of nitrides and iron

Author

Leineweber, Andreas, Aufrecht, Jochen, and Mittemeijer, Eric Jan

Abstract

Annealing at low temperatures (T< 670 K) of mixtures of iron nitride powders and iron powder is shown to induce phase transformations through nitrogen transfer between different powder particles. This nitrogen transfer occurs via loose mechanical contact points between different powder particles; nitrogen transport via the gas phase can be excluded. Unique scientific possibilities offered by this type of phase transformation studies are discussed.

Published
2022
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19. The Pd-rich part of the Pd–B phase diagram

Author

Georg Berger, Tilmann, Leineweber, Andreas, and Mittemeijer, Eric Jan

Abstract

The Pd–B system in the composition range of the solid solution PdByhas been the subject of a number of investigations as it provides an attractive model system for interstitial compounds. No consensus about the crystal structures and phase boundaries, particularly in the low-temperature regime, has been reached in the earlier works. In the light of very recent results on the crystal structure and composition ranges of the low-temperature phases, on the basis of X-ray, electron, and neutron diffraction analyses, a tentative phase diagram is presented which is compatible with practically all previous results.

Published
2022
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20. Influences of Material Inhomogeneities in 100Cr6 Steel on the Electrochemical Metal Dissolution Process

Author

Haisch, Thomas, Mittemeijer, Eric Jan, and Schultze, Joachim Walter

Abstract

The electrochemical metal dissolution of 100Cr6 steel in sodium chloride solution, applying high electrolyte flow rates and high current densities, has been studied with a view to the influence of material heterogeneities such as carbide segregation lines in the steel matrix. It was shown that the presence of such segregations is responsible for the formation of troughs on the specimen surface during electrochemical dissolution. A mechanism for trough formation was proposed. A dedicated heat treatment applied to the 100Cr6 steel eliminated the carbide segregation lines and established a soft annealed, fine-grained microstructure containing globular carbides. Subsequent electrochemical dissolution did not show any development of surface irregularities as troughs.^

Published
2022
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34. The Nitrogen-absorption Isotherm for Fe-21.5at.%Cr Alloy: Uptake of Excess Nitrogen in Dependence on the Precipitation Morphology

Author

Hosmani, Santosh, Schacherl, Ralf, Lityńska-Dobrzyńska, Lidia, Mittemeijer, Eric Jan, Max Planck Institute for Metals Research, Institute of Physical Metallurgy, University of Stuttgart, Institute of Metallurgy and Materials Science, and Polska Akademia Nauk = Polish Academy of Sciences (PAN)

Subjects
Physical Sciences, technology, industry, and agriculture
Abstract

International audience; Nitriding of Fe-21.5at.%Cr alloy leads to a “discontinuously coarsened”, chromium-nitride/ferrite lamellar precipitation morphology in the nitrided zone. The nitrogen-absorption isotherm for this alloy with this precipitation morphology was determined at 560 °C. To assure a constant precipitation morphology the Fe-21.5at.%Cr specimen was first homogeneously pre-nitrided (at 580 ºC in an ammonia/hydrogen gas mixture of nitriding potential of 0.103 atm-1/2) and then de-nitrided (at 470 ºC in hydrogen gas atmosphere). The amount of nitrogen remaining in the de-nitrided specimen indicated that the composition of the nitride precipitates is CrN and not (Fe, Cr)N. The measured nitrogen-absorption isotherm revealed the presence of excess nitrogen in the nitrided specimen, which is a surprise in view of the coarse, lamellar precipitation morphology. The occurrence of this excess nitrogen could be ascribed to an unexpected, minor fraction of the total chromium content in the alloy present as coherent, tiny nitride platelets within the ferrite lamellae of the “discontinuously coarsened” lamellar precipitation morphology, as evidenced by transmission electron microscopy. A possible kinetic background for this unusual phenomenon was discussed.

Published
2008

39. Redetermination of the crystal structure of the Ag3Sn intermetallic compound.

Author

Rossi, Paul Josef, Zotov, Nikolay, and Mittemeijer, Eric Jan

Subjects
INTERMETALLIC compounds, X-ray powder diffraction, ORTHORHOMBIC crystal system, CRYSTAL structure research, SILVER
Abstract

Ambiguity exists in the literature on the crystal structure of Ag3Sn: no agreement on neither the type of orthorhombic distortion nor the presence of ordering exists. Therefore, the exact crystal structure of Ag3Sn has been reinvestigated using high resolution X-ray powder dffraction. By applying Rietveld refinements, it could be shown that Ag3Sn is orthorhombic, with an ordered crystal structure of *#946;-Cu3Ti-type (space group Pmmn). The lattice parameters of a Sn-rich and an Ag-rich sample are a = 4.78233(1) Å, b = 5.99752(1) Å, c = 5.16393(1) Å and a = 4.78291(2) Å, b = 5.98854(2) Å, c = 5.15686(2) Å, respectively. The lattice parameters indicate k-type orthorhombic distortion. [ABSTRACT FROM AUTHOR]

Published
2016
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