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Academic literature on the topic 'Amorphization'

Author: Grafiati

Published: 4 June 2021

Last updated: 22 June 2024

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Journal articles on the topic "Amorphization"

1

Gratz, A. J., L. D. DeLoach, T. M. Clough, and W. J. Nellis. "Shock Amorphization of Cristobalite." Science 259, no. 5095 (January 29, 1993): 663–66. http://dx.doi.org/10.1126/science.259.5095.663.

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Shock amorphization of cristobalite is reported and related to shock metamorphism of quartz, both being silicon dioxide polymorphs. Whereas amorphization of quartz takes place over a broad pressure range and is complete only at 35 to 40 gigapascals (350 to 400 kilobars), amorphization of cristobalite was complete (greater than 99.9 percent) by 28 gigapascals with a relatively sharp phase transformation; lower shock pressures up to 23 gigapascals resulted in no significant amorphization. Also, unlike quartz, there was no sign of lamellar amorphization, which is common in shock compression. Cristobalite amorphization should prove a useful indicator of shock pressure and is the first case of pressure amorphization of isochemical polymorphs. The diaplectic glass that is produced has a refractive index and density essentially identical to those of the diaplectic glass made from quartz, which suggests that both polymorphs collapse during shock to similar disordered phases.

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Tsuchiya, Koichi, and Octav Ciuca. "Nanostructure Formation and Amorphization in Intermetallic Compounds by Severe Plastic Deformation." Materials Science Forum 667-669 (December 2010): 17–24. http://dx.doi.org/10.4028/www.scientific.net/msf.667-669.17.

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Process of nanostructure formation and amorphization by high pressure torsion (HPT) were studied for various intermetallic compounds. In ZrCu after HPT deformation, optical microscopy revealed that numerous shear bands formed running nearly parallel to the shear direction. Partial amorphization was confirmed by X-ray diffraction and TEM observations. Detailed TEM observations revealed localized amorphization within the nano-scale shear bands. For HPT deformation of zone-melted Zr50Cu40Al10 the preferential amorphization of ZrCu phase was observed. On the contrary, amorphization was not observed for Ni3Al even after HPT deformation of 100 turns; the sample remained to be disordered nanocrystalline of about 50 nm. The process and mechanism of the grain refinement and amorphization will be compared and discussed for these intermetallic compounds.

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Eby, Ray K., Rodney C. Ewing, and Robert C. Birtcher. "The amorphization of complex silicates by ion-beam irradiation." Journal of Materials Research 7, no. 11 (November 1992): 3080–102. http://dx.doi.org/10.1557/jmr.1992.3080.

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Twenty-five silicates were irradiated at ambient temperature conditions with 1.5 MeV Kr+. Critical doses of amorphization were monitored in situ with transmission electron microscopy. The doses required for amorphization are compared with the structures, bond-types, compositions, and physical properties of the silicates using simple correlation methods and more complex multivariate statistical analysis. These analyses were made in order to determine which properties most affect the critical amorphization dose. Simple two-variable correlations indicate that melting point, efficiency of atomic packing, the dimensionality of SiO4 polymerization (DOSP), and bond ionicity have a relationship with critical amorphization dose. However, these relationships are evident only in selected portions of the data set; that is, for silicate phases with a common structure type. A clearer relationship between the silicate properties and critical amorphization dose was determined for the entire data set with multiple linear regression. Several regression models are proposed which describe the variation in amorphization dose. All regression models contain the following properties: (i) melting point; (ii) a structural variable (DOSP, elastic modulus, and/or atomic packing); and (iii) the proportion of Si–O bonding (instead of bond ionicity). The regression models are equivalent, because they represent combinations of similar properties. Notably, density and atomic mass are not controlling properties for the critical amorphization dose. Melting and amorphization by ion irradiation are apparently related processes. Neither melting point nor critical amorphization dose can be predicted by considering only the structure, composition, or bonding of a particular phase. The Si–O bond is the most covalent bond in silicates, and is the “weak link” in the structure with respect to amorphization. Thus, DOSP is also an important property, as the topology of these “weak links” influences a structure's ability to accumulate amorphous regions. The efficiency of atomic packing is related to the process of defect self-recombination during amorphization. The bulk modulus and shear modulus are important variables within the regression models because of their direct relationship to atomic packing.

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Hempel, Nele-Johanna, Matthias M. Knopp, Ragna Berthelsen, and Korbinian Löbmann. "Convection-Induced vs. Microwave Radiation-Induced in situ Drug Amorphization." Molecules 25, no. 5 (February 27, 2020): 1068. http://dx.doi.org/10.3390/molecules25051068.

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The aim of the study was to investigate the suitability of a convection oven to induce in situ amorphization. The study was conducted using microwave radiation-induced in situ amorphization as reference, as it has recently been shown to enable the preparation of a fully (100%) amorphous solid dispersion of celecoxib (CCX) in polyvinylpyrrolidone (PVP) after 10 min of continuous microwaving. For comparison, the experimental setup of the microwave-induced method was mimicked for the convection-induced method. Compacts containing crystalline CCX and PVP were prepared and either pre-conditioned at 75% relative humidity or kept dry to investigate the effect of sorbed water on the amorphization kinetics. Subsequently, the compacts were heated for 5, 10, 15, 20, or 30 min in the convection oven at 100 °C. The degree of amorphization of CCX in the compacts was subsequently quantified using transmission Raman spectroscopy. Using the convection oven, the maximum degree of amorphization achieved was 96.1% ± 2.1% (n = 3) for the conditioned compacts after 30 min of heating and 14.3% ± 1.4% (n = 3) for the dry compacts after 20 min of heating, respectively. Based on the results from the convection and the microwave oven, it was found that the sorbed water acts as a plasticizer in the conditioned compacts (i.e., increasing molecular mobility), which is advantageous for in situ amorphization in both methods. Since the underlying mechanism of heating between the convection oven and microwave oven differs, it was found that convection-induced in situ amorphization is inferior to microwave radiation-induced in situ amorphization in terms of amorphization kinetics with the present experimental setup.

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Chen, Z. Q., F. Wang, P. Huang, T. J. Lu, and K. W. Xu. "Low-Temperature Annealing Induced Amorphization in Nanocrystalline NiW Alloy Films." Journal of Nanomaterials 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/252965.

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Annealing induced amorphization in sputtered glass-forming thin films was generally observed in the supercooled liquid region. Based on X-ray diffraction and transmission electron microscope (TEM) analysis, however, here, we demonstrate that nearly full amorphization could occur in nanocrystalline (NC) sputtered NiW alloy films annealed at relatively low temperature. Whilst the supersaturation of W content caused by the formation of Ni4W phase played a crucial role in the amorphization process of NiW alloy films annealed at 473 K for 30 min, nearly full amorphization occurred upon further annealing of the film for 60 min. The redistribution of free volume from amorphous regions into crystalline regions was proposed as the possible mechanism underlying the nearly full amorphization observed in NiW alloys.

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Richet, Pascal, and Philippe Gillet. "Pressure-induced amorphization of minerals: a review." European Journal of Mineralogy 9, no. 5 (September 24, 1997): 907–34. http://dx.doi.org/10.1127/ejm/9/5/0907.

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Luzzi, D. E., and M. Meshii. "High-resolution electron microscopy of amorphization of Cu4 Ti3." Journal of Materials Research 1, no. 5 (October 1986): 617–28. http://dx.doi.org/10.1557/jmr.1986.0617.

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The electron irradiation-induced, crystalline-to-amorphous transition was studied in the intermetallic compound Cu4Ti3 by high-resolution electron microscopy. Using highresolution maps from the crystalline region into the amorphized region, the amorphization process and the amorphous structure were examined. The extent of chemical order in crystalline regions just prior to amorphization was studied by simultaneously imaging superlattice and fundamental lattice fringe contrast. The chemical order continuously decreased in these regions but faint superlattice contrast was recognized as long as the crystalline feature remained on the image, supporting the theory that chemical disordering is the major driving force for amorphization. The amorphization process appears to be evolutionary, leading to a nanocrystalline type of amorphous structure. A model of the amorphization process is proposed based on the present results and those from previous studies.

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SUITO, Kaichi. "Pressure-Induced Amorphization." Journal of the Society of Materials Science, Japan 42, no. 474 (1993): 333–38. http://dx.doi.org/10.2472/jsms.42.333.

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9

Ewing, R. C., A. Meldrum, L. Wang, and S. Wang. "Radiation-Induced Amorphization." Reviews in Mineralogy and Geochemistry 39, no. 1 (January 1, 2000): 319–61. http://dx.doi.org/10.2138/rmg.2000.39.12.

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Lam, Nghi Q., Paul R. Okamoto, and Mo Li. "Disorder-induced amorphization." Journal of Nuclear Materials 251 (November 1997): 89–97. http://dx.doi.org/10.1016/s0022-3115(97)00257-2.

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Dissertations / Theses on the topic "Amorphization"

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Cao, Shuai. "Nanostructured metal-organic frameworks and their amorphization, carbonization and applications." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.707948.

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Puthucode, Balakrishnan Anantharamakrishnan Kaufman Michael Joseph. "Amorphization and de-vitrification in immiscible copper-niobium alloy thin films." [Denton, Tex.] : University of North Texas, 2007. http://digital.library.unt.edu/permalink/meta-dc-3626.

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Puthucode, Balakrishnan Anantharamakrishnan. "Amorphization and De-vitrification in Immiscible Copper-Niobium Alloy Thin Films." Thesis, University of North Texas, 2007. https://digital.library.unt.edu/ark:/67531/metadc3626/.

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While amorphous phases have been reported in immiscible alloy systems, there is still some controversy regarding the reason for the stabilization of these unusual amorphous phases. Direct evidence of nanoscale phase separation within the amorphous phase forming in immiscible Cu-Nb alloy thin films using 3D atom probe tomography has been presented. This evidence clearly indicates that the nanoscale phase separation is responsible for the stabilization of the amorphous phase in such immiscible systems since it substantially reduces the free energy of the undercooled liquid (or amorphous) phase, below that of the competing supersaturated crystalline phases. The devitrification of the immiscible Cu-Nb thin film of composition Cu-45% Nb has been studied in detail with the discussion on the mechanism of phase transformation. The initial phase separation in the amorphous condition seems to play a vital role in the crystallization of the thin film. Detailed analysis has been done using X-ray diffraction, transmission electron microscopy and 3D atom probe tomography.

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Vaseashta, Ashok K. "Photonic studies of defects and amorphization in ion beam damaged GaAs surfaces." Diss., This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-08082007-170507/.

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Sun, Xuejiao. "Structure and dynamic processes involved in the amorphization of zeolite Y with different cations." Thesis, Aberystwyth University, 2018. http://hdl.handle.net/2160/84f5b229-ee45-4f93-b7bd-69b33cd7f77e.

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Zeolites, as promising raw materials for making glass, have been studied for many years. Their framework structures provide them with properties different from other mineral materials, such as low density, water absorption capacity and ion exchange property. Building from subunit cages, zeolites have a huge family with different properties and topologies. Sodium zeolite Y can be mass-produced and is easy to obtain which is therefore the studied material in this thesis. Although some researches have been done on glass formation from zeolites, many aspects in the amorphization process including thermodynamics, structural changes, dynamical changes need more study. Further more, study on glass formation from ion exchanged zeolite glass is now a new research topic. In this thesis, ex situ temperature induced amorphization of sodium zeolite Y (Na58Al58Si134O384·212H2O) has been studied. Multiple techniques were used to investigate different properties of it. Differential scanning calorimetry (DSC) was conducted to study the thermal properties of Na zeolite Y, finding that the structural collapse happens over a large temperature range covering 200K, in which the speed of collapse accelerates with higher temperature. Therefore, three target temperatures were chosen in this range to amorphize Na zeolite Y using different lengths of heating time to obtain samples with different degree of amorphization. These amorphous samples are then studied by X-ray powder diffraction (XRPD) and High resolution X-ray powder diffraction (HR-XRPD) to detect their structural changes during collapse. The data were analyzed by Rietveld Methods (TOPAS software), finding that the amorphization shrinks the cage topology, and makes the charge-compensating Na ion move to sodalite cages and double 6-fold rings (D6R), which are smaller than the super cages. Raman spectroscopy was also used to study the dynamics of Na zeolite Y and its amorphization. The band of 4-fold and 6-fold rings which make up the cages can be clearly seen in the Raman spectra of crystalline zeolite Y, along with a small stretching mode peak feature. When amorphization take place, the peaks for 4- and 6-fold rings will first decrease then grow again suggesting the disappearance and regrowth of the rings. Some new rings like 5-fold rings appear after collapse similar to other dense alumina silicate glasses. Inelastic neutron scattering (INS) was also used to detect the dynamic properties of the Na zeolite Y, suggesting that the cage structure shrinks with amorphization. Ion exchange can make a lot of changes to the properties of the Na zeolite Y before and after amorphization, therefore, Cu and Nd exchanged zeolite Y are also studied in this thesis. Studied by DSC, the ion exchanged zeolite Y shows higher collapse temperature and faster collapse within amorphization range. This can be caused by the higher field strength and different cation occupancy of the ion exchanged species. Samples with different degrees of amorphization were studied by XRPD and HR-XRPD similar to Na zeolite Y, finding that the exchanged ion shrinks the unit cell in proportion to their higher field strength and smaller ionic sizes in the order Na-Nd-Cu. However, the movement of the cation caused by the heat treatment during amorphization makes different influence on the Nd and Cu exchanged zeolite. The unit cell size of amorphous Cu zeolite Y becomes larger than crystalline Cu zeolite Y, but still smaller than the crystalline Na zeolite Y. This is due to high field strength of the Cu2+ cation and movement of the cations from supercage to sodalite cage. The change of the amorphous Nd zeolite Y is similar to that occurring in Na zeolite Y. Raman spectroscopy for Cu zeolite Y showed quite different features to Na zeolite Y and Nd zeolite Y, the latter two being similar to one another. In Cu zeolite Y the 4-fold and 6-fold peaks diminish in intensity slightly and then grow, when new features like 5-fold rings appearing. The band for 6-fold rings dominates the features of 4- and 5-fold rings, indicating a change in topology for Cu exchanged zeolite Y. This thesis includes suggestions for further work to confirm the findings. Taken together, these findings contribute to the expanding literature of zeolite amorphization and may find commercialization applications.

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Monsegue, Niven. "Characterizing the Effects of Mechanical Alloying on Solid State Amorphization of Nanoscaled Multilayered Ni-Ti." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/28373.

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Equiatomic composition of Ni and Ti was cryomilled with varying milling times to create Ni-Ti lamella structures with average spacings of 50 nm, 470 nm, and 583 nm in powder particles to vary the interfacial surface area per volume. These surfaces form interfaces for diffusion that are essential for solid state amorphization during low temperature annealing. To compare solid state amorphization in a relatively defect free multilayer system, elemental Ni and Ti were deposited by electron beam physical vapor deposition on titanium plates with comparable spacing as above. Both milled and deposited multilayers were annealed between 225 and 350°C for up to 50 hours. X-ray diffraction characterization and in situ annealing was conducted on cryomilled and deposited multilayers of Ni-Ti. Based on this characterization, an amorphization model based on the Johnson-Mehl-Avrami nucleation and growth equation has been established to predict the amorphization of both cryomilled and deposited multilayers. Cryomilled powders experienced much larger amorphization rates during annealing than that of deposited multilayer structures, for all layer spacings. This superior amorphization is seen despite the formation of amorphous phase during the milling process; the amount of which increases with increasing milling time. The difference in amorphization rates between cryomilled and deposited multilayers is attributed to excess driving force due to the extensive preexisting defects in the powders caused by cryomilling. Serial 3D reconstruction of cryomilled Ni-Ti powders was done by scanning electron microscopy and focused ion beam. Through 3D reconstruction it was observed that a random and non-linear lamella structure has been formed in cryomilled powders. Furthermore, lamellar spacing was seen to become smaller with increased milling time while at the same time becoming more homogeneous through the material's volume. 3D reconstruction of cryomilled Ni-Ti offers a unique insight into the microstructures and surface areas of cryomilled powder particles that has never been accomplished.
Ph. D.

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Gotoshia, S. V., and L. V. Gotoshia. "Laser Raman-Spectroscopy of Phase Transformation in the Near Surface of GaP." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35159.

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When implanting GaP with boron and heavier argon ions, severe distortion of crystal structure occurs. Raman scattering has shown that with implanted ion dose change the crystal structure transforms gradually into disordered state, in which coexisting of crystalline, microcrystalline, nanocrystalline and amorphous phases is possible. At the certain stage of implantation the formation of continuous amorphous layer of GaP takes place. The critical doses of amorphization of GaP at implantation with B and Ar ions have been defined. The graph of dependence of LO phonon halfwidths upon implantation doses is also a characteristic of synthesizing of nano-GaP. We suggest a possible mechanism for structural transition dynamics in GaP caused by ion implantation. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35159

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Hickey, Diane P. "Ion implantation induced defect formation and amorphization in the Group IV semiconductors: diamond, silicon, and germanium /." [Gainesville, Fla.] : University of Florida, 2007. http://purl.fcla.edu/fcla/etd/UFE0021224.

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Thomeny, Girao Helainne. "Pressure-induced disorder in bulk and nanometric SnO2." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1176/document.

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Les matériaux nanométriques ont fait l'objet d'un intérêt de recherche important car ils présentent de nouvelles propriétés physiques et chimiques par rapport aux échantillons massifs. En ce qui concerne les nanomatériaux, l'effet de taille et l'énergie de surface sont généralement invoqués, même si les concepts sous-jacents ne sont pas clairs. Dans cette thèse, la question principale à laquelle nous voulons répondre est : quels sont les principaux paramètres qui régissent la stabilité structurelle du SnO2 à l’échelle nanométrique sous haute pression comparé aux échantillons de SnO2 massifs ? La combinaison de la haute pression et de la taille des particules est particulièrement importante pour comprendre la structure de ces nanoparticules et l'effet des défauts et de l'énergie de surface sur leur stabilité de phase, car, en gardant la taille des particules constante, l'augmentation de la pression permettra l'exploration les paysages énergétiques du système. De plus, la pression et la taille sont deux paramètres qui peuvent être utilisés conjointement pour stabiliser les nouvelles phases. L'intérêt de l'étude des nanoparticules sous haute pression est au moins double : (i) acquérir une compréhension fondamentale de la thermodynamique lorsque l'énergie interfaciale devient de la même ampleur que l'énergie interne (ii) pour stabiliser de nouvelles structures potentiellement potentielles intérêt en tant que matériaux fonctionnels. Dans ce travail, nous avons utilisé la spectroscopie Raman comme principale méthode de caractérisation. Pour les échantillons de SnO2 massif, nous avons utilisé la théorie de la percolation pour expliquer la désordre « partiel » du sous-réseau oxygène qui apparaît lorsque la pression augmente, ce qu’on appelle désordre « partiel » induite par la pression. Et, en étudiant les nanoparticules de SnO2, nous avons utilisé des simulations ab initio pour expliquer l'apparition de ce type de désordre, cet à dire, le désordre du sous-réseau anionique lorsque la pression augmente. De cette façon, nous proposons d'obtenir une compréhension fondamentale du SnO2 massif et nanométrique, sous pression
Nanosized materials have been the focus of an extensive interest research as they present new physical and chemical properties in comparison to their bulk equivalent. When dealing with nanomaterials, the size effect and the surface energy are generally invoked, even though the underlying concepts are not clear. In this thesis, the main question that we want to answer is: what are the main parameters which govern the structural stability at the SnO2 nanometric under high pressure in comparison to its bulk counterpart? The combination of high pressure and particle size is particularly important in order to understand the nanoparticle structure, and the effect of the defects and of the surface energy on phase stability. By maintaining the size of the particle constant, the pressure will allow the energy landscapes of the system to be explored. In addition, pressure and size are two parameters that can be used conjointly in order to stabilize new phases. So, the interest of studying nanoparticles under the high-pressure is at least two-fold: (i) to gain a fundamental understanding of thermodynamics when the interfacial energy reaches the same magnitude as the internal energy (ii) to stabilize new structures that may have potential interest as functional materials. In this work, we used Raman spectroscopy as the main characterization method. In the study of SnO2 bulk samples, we used percolation to explain the “partial” disorder of the oxygen sublattice which appears in the powders when the pressure increases; and for studying SnO2 nanoparticles, we used ab initio simulations to explain the appearance of this kind of disorder, i.e. the anionic sublattice disorder in SnO2 nanoparticle samples. In this way, we propose to obtain a fundamental understanding of SnO2 bulk and nanoparticles under pressure

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Kucheyev, Sergei Olegovich, and kucheyev1@llnl gov. "Ion-beam processes in group-III nitrides." The Australian National University. Research School of Physical Sciences and Engineering, 2002. http://thesis.anu.edu.au./public/adt-ANU20030211.170915.

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Group-III-nitride semiconductors (GaN, InGaN, and AlGaN) are important for the fabrication of a range of optoelectronic devices (such as blue-green light emitting diodes, laser diodes, and UV detectors) as well as devices for high-temperature/high-power electronics. In the fabrication of these devices, ion bombardment represents a very attractive technological tool. However, a successful application of ion implantation depends on an understanding of the effects of radiation damage. Hence, this thesis explores a number of fundamental aspects of radiation effects in wurtzite III-nitrides. Emphasis is given to an understanding of (i) the evolution of defect structures in III-nitrides during ion irradiation and (ii) the influence of ion bombardment on structural, mechanical, optical, and electrical properties of these materials. ¶ Structural characteristics of GaN bombarded with keV ions are studied by Rutherford backscattering/channeling (RBS/C) spectrometry and transmission electron microscopy (TEM). Results show that strong dynamic annealing leads to a complex dependence of the damage buildup on ion species with preferential surface disordering. Such preferential surface disordering is due to the formation of surface amorphous layers, attributed to the trapping of mobile point defects by the GaN surface. Planar defects are formed for a wide range of implant conditions during bombardment. For some irradiation regimes, bulk disorder saturates below the amorphization level, and, with increasing ion dose, amorphization proceeds layer-by-layer only from the GaN surface. In the case of light ions, chemical effects of implanted species can strongly affect damage buildup. For heavier ions, an increase in the density of collision cascades strongly increases the level of stable implantation-produced lattice disorder. Physical mechanisms of surface and bulk amorphization and various defect interaction processes in GaN are discussed. ¶ Structural studies by RBS/C, TEM, and atomic force microscopy (AFM) reveal anomalous swelling of implanted regions as a result of the formation of a porous structure of amorphous GaN. Results suggest that such a porous structure consists of N$_{2}$ gas bubbles embedded into a highly N-deficient amorphous GaN matrix. The evolution of the porous structure appears to be a result of stoichiometric imbalance, where N- and Ga-rich regions are produced by ion bombardment. Prior to amorphization, ion bombardment does not produce a porous structure due to efficient dynamic annealing in the crystalline phase. ¶ The influence of In and Al content on the accumulation of structural damage in InGaN and AlGaN under heavy-ion bombardment is studied by RBS/C and TEM. Results show that an increase in In concentration strongly suppresses dynamic annealing processes, while an increase in Al content dramatically enhances dynamic annealing. Lattice amorphization in AlN is not observed even for very large doses of keV heavy ions at -196 C. In contrast to the case of GaN, no preferential surface disordering is observed in InGaN, AlGaN, and AlN. Similar implantation-produced defect structures are revealed by TEM in GaN, InGaN, AlGaN, and AlN. ¶ The deformation behavior of GaN modified by ion bombardment is studied by spherical nanoindentation. Results show that implantation disorder significantly changes the mechanical properties of GaN. In particular, amorphous GaN exhibits plastic deformation even for very low loads with dramatically reduced values of hardness and Young's modulus compared to the values of as-grown GaN. Moreover, implantation-produced defects in crystalline GaN suppress the plastic component of deformation. ¶ The influence of ion-beam-produced lattice defects as well as a range of implanted species on the luminescence properties of GaN is studied by cathodoluminescence (CL). Results indicate that intrinsic lattice defects mainly act as nonradiative recombination centers and do not give rise to yellow luminescence (YL). Even relatively low dose keV light-ion bombardment results in a dramatic quenching of visible CL emission. Postimplantation annealing at temperatures up to 1050 C generally causes a partial recovery of measured CL intensities. However, CL depth profiles indicate that, in most cases, such a recovery results from CL emission from virgin GaN, beyond the implanted layer, due to a reduction in the extent of light absorption within the implanted layer. Experimental data also shows that H, C, and O are involved in the formation of YL. The chemical origin of YL is discussed based on experimental data. ¶ Finally, the evolution of sheet resistance of GaN epilayers irradiated with MeV light ions is studied {\it in-situ}. Results show that the threshold dose of electrical isolation linearly depends on the original free electron concentration and is inversely proportional to the number of atomic displacements produced by the ion beam. Furthermore, such isolation is stable to rapid thermal annealing at temperatures up to 900 C. Results also show that both implantation temperature and ion beam flux can affect the process of electrical isolation. This behavior is consistent with significant dynamic annealing, which suggests a scenario where the centers responsible for electrical isolation are defect clusters and/or antisite-related defects. A qualitative model is proposed to explain temperature and flux effects. ¶ The work presented in this thesis has resulted in the identification and understanding of a number of both fundamental and technologically important ion-beam processes in III-nitrides. Most of the phenomena investigated are related to the nature and effects of implantation damage, such as lattice amorphization, formation of planar defects, preferential surface disordering, porosity, decomposition, and quenching of CL. These effects are often technologically undesirable, and the work of this thesis has indicated, in some cases, how such effects can be minimized or controlled. However, the thesis has also investigated one example where irradiation-produced defects can be successfully applied for a technological benefit, namely for electrical isolation of GaN-based devices. Finally, results of this thesis will clearly stimulate further research both to probe some of the mechanisms for unusual ion-induced effects and also to develop processes to avoid or repair unwanted lattice damage produced by ion bombardment.

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Books on the topic "Amorphization"

1

Motta, A. T. Amorphization kinetics of Zr3Fe under electron irradiation. Chalk River, Ont: Chalk River Laboratories, 1994.

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Motta, A. T. Amorphization kinetics of Zr(Cr, Fe)₂ under ion irradiation. Chalk River, Ont: AECL Research, 1994.

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Motta, A. T. Amorphization kinetics of Zr(Cr, Fe)2 under ion irradiation. Chalk River, Ont: Chalk River Laboratories, 1994.

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Termentzidis, Konstantinos. Nanostructured Semiconductors: Amorphization and Thermal Properties. Jenny Stanford Publishing, 2017.

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Termentzidis, Konstantinos. Nanostructured Semiconductors: Amorphization and Thermal Properties. Jenny Stanford Publishing, 2017.

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Beck, Hans, and Hans-Joachim Guntherodt. Glassy Metals III: Amorphization Techniques, Catalysis, Electronic and Ionic Structure. Springer, 2013.

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Beck, H. Glassy Metals III: Amorphization Techniques, Catalysis, Electronic and Ionic Structure (Topics in Applied Physics). Springer, 1994.

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Book chapters on the topic "Amorphization"

1

Ewing, Rodney C., Alkiviathes Meldrum, LuMin Wang, and ShiXin Wang. "12. Radiation-Induced Amorphization." In Transformation Processes in Minerals, edited by Simon A. Redfern and Michael A. Carpenter, 319–62. Berlin, Boston: De Gruyter, 2000. http://dx.doi.org/10.1515/9781501509155-013.

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Motta, Arthur T., and Clement Lemaignan. "Mechanisms of Radiation Induced Amorphization." In Ordering and Disordering in Alloys, 255–76. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2886-5_28.

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Gerl, M., and P. Guilmin. "Amorphization by Solid State Reaction." In Diffusion in Materials, 625–42. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-1976-1_32.

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Sieber, Heino, Gerhard Wilde, Alexander Sagel, and John H. Perepezko. "Solid State Amorphization by Cold-Rolling." In Materials Development and Processing - Bulk Amorphous Materials, Undercooling and Powder Metallurgy, 1–9. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/3527607277.ch1.

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Yip, Sidney, Simon R. Phillpot, and Dieter Wolf. "Crystal Disordering in Melting and Amorphization." In Handbook of Materials Modeling, 2009–23. Dordrecht: Springer Netherlands, 2005. http://dx.doi.org/10.1007/1-4020-3286-2_104.

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Yip, Sidney, Simon R. Phillpot, and Dieter Wolf. "Crystal Disordering in Melting and Amorphization." In Handbook of Materials Modeling, 2009–23. Dordrecht: Springer Netherlands, 2005. http://dx.doi.org/10.1007/978-1-4020-3286-8_104.

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Yamanaka, T., T. Shibata, S. Kawasaki, and S. Kume. "Pressure Induced Amorphization of Hexagonal GeO2." In High-Pressure Research: Application to Earth and Planetary Sciences, 493–501. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm067p0493.

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Yurachkivsky, A. P., and G. G. Shapovalov. "On the Kinetics of Amorphization Under Ion Implantation." In Frontiers in Nanoscale Science of Micron/Submicron Devices, 413–16. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-1778-1_30.

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Zhang, Yanwen, and William J. Weber. "Defect Accumulation, Amorphization and Nanostructure Modification of Ceramics." In Ion Beam Modification of Solids, 287–318. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-33561-2_7.

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Williams, J. S., G. de M. Azevedo, H. Bernas, and F. Fortuna. "Ion-Beam-Induced Amorphization and Epitaxial Crystallization of Silicon." In Topics in Applied Physics, 73–111. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-88789-8_4.

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Conference papers on the topic "Amorphization"

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Nakagawa, Sachiko T. "Physics of amorphization." In 2011 11th International Workshop on Junction Technology (IWJT). IEEE, 2011. http://dx.doi.org/10.1109/iwjt.2011.5969996.

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Ren, Zhencheng, Chang Ye, and Yalin Dong. "Molecular Dynamic Simulation of Surface Amorphization of NiTi Under Dynamic Shock Peening." In ASME 2015 International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/msec2015-9320.

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Surface amorphization of NiTi has been achieved by ultra-high strain rate dynamic loading induced by ultrasonic nano-crystal surface modification (UNSM). The amorphous microstructure was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). To better understand the physical mechanism of the amorphization process, molecular dynamics (MD) simulation has been implemented to simulate the shock loading process and the results are consistent with the experiment. Central-symmetry parameter (CSP) and radial distribution function (RDF) were used to characterize the microstructure evolution. The simulation result demonstrates that the deformation is first formed as “twining” structure and then transformed into amorphization. The simulation also shows that shock speeds affect the amorphization level on the surface, while the shock amplitude mainly affects the amorphization depth.

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Sikka, S. K., and Satish C. Gupta. "Shock induced amorphization of materials." In The tenth American Physical Society topical conference on shock compression of condensed matter. AIP, 1998. http://dx.doi.org/10.1063/1.55478.

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Uvarov, N. F., A. A. Politov, and B. B. Bokhonov. "AMORPHIZATION OF IONIC SALTS IN NANOCOMPOSITES." In Proceedings of the 7th Asian Conference. WORLD SCIENTIFIC, 2000. http://dx.doi.org/10.1142/9789812791979_0015.

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Okulich, Evgeniya, Victor Okulich, and David Tetelbaum. "ESTIMATION OF THE DOSE OF SILICON AMORPHIZATION IN A WIDE RANGE OF ION IMPLANTATION PARAMETERS WITH LIGHT IONS." In International Forum “Microelectronics – 2020”. Joung Scientists Scholarship “Microelectronics – 2020”. XIII International conference «Silicon – 2020». XII young scientists scholarship for silicon nanostructures and devices physics, material science, process and analysis. LLC MAKS Press, 2020. http://dx.doi.org/10.29003/m1579.silicon-2020/133-136.

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There are presented the results of calculating the dose of silicon amorphization by light ions (He+, B+, N+, Si+, and P+) depending on the parameters of ion implantation. A method for calculating the dose of amorphization of silicon in the region of the gate dielectric is proposed.

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Ye, Chang, and Gary J. Cheng. "Controlled Nanocrystallization of NiTi Shape Memory Alloy by Laser Shock Peening." In ASME 2011 International Manufacturing Science and Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/msec2011-50294.

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In this paper, partial amorphization of NiTi alloys by laser shock peening (LSP) is reported. The microstructure of NiTi after LSP was characterized by transmission electron microscopy (TEM). The amorphization mechanism was discussed in light of the high strain rate deformation characteristics of LSP. With subsequent controlled annealing after LSP, nanostructure with different grain size distribution was achieved.

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CHEN, L. J., H. L. HSIAO, and H. F. HSU. "SOLID STATE AMORPHIZATION IN METAL-SI SYSTEMS." In Proceedings of the 8th Asia-Pacific Physics Conference. WORLD SCIENTIFIC, 2001. http://dx.doi.org/10.1142/9789812811523_0017.

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Lian, J., R. C. Ewing, S. V. Yudintsev, and S. V. Stefanovsky. "Radiation Stability of Melted Titanate Waste Forms for Actinide Immobilization." In ASME 2001 8th International Conference on Radioactive Waste Management and Environmental Remediation. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/icem2001-1316.

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Abstract Radiation stability of titanate ceramics suggested for actinide-bearing waste immobilization was studied. The major actinide (uranium) hosts in the samples prepared by melting followed by crystallization in a resistive furnace and in a cold crucible are phases with fluorite-related structure (zirconolite, pyrochlore, murataite) as well as brannerite. Critical amorphization doses at room temperature for these phases irradiated with 1 MeV Kr+ ions were (× 1018 ions/m2) ∼3, 1.8–2.4, 1.7–1.9, and 1.4 for zirconolite, pyrochlore, murataite, and brannerite, respectively. Murataite varieties with three-, five-, and eight-fold fluorite cells have the similar radiation stability. Recalculation of critical amorphization dose to dpa estimates a time required for murataite amorphization as 600–700 years at 10 wt.% 239Pu content. Similar values have been established previously for pyrochlore-structured titanates proposed for plutonium immobilization (because there will be also some commercial Pu issue).

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Motooka, T., F. Kobayashi, P. Fons, T. Tokuyama T. Suzuki, and N. Natsuaki. "Amorphization Processes in Ion Implanted Si: Temperature Dependence." In 1991 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 1991. http://dx.doi.org/10.7567/ssdm.1991.b-1-3.

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Chen, Pin Hong, Chia Chang Hsu, Jerander Lai, Boris Liao, Chun Ling Lin, Olivia Huang, Chun Chieh Chiu, C. M. Hsu, and J. Y. Wu. "Investigation pre-amorphization implantation on nickel silicide formation." In 2014 IEEE International Interconnect Technology Conference / Advanced Metallization Conference (IITC/AMC). IEEE, 2014. http://dx.doi.org/10.1109/iitc.2014.6831887.

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Reports on the topic "Amorphization"

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Ewing, R. C., and Lu-Min Wang. Particle-induced amorphization complex ceramic. Office of Scientific and Technical Information (OSTI), February 1996. http://dx.doi.org/10.2172/269048.

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Snead, L. L., and J. C. Hay. Neutron irradiation induced amorphization of silicon carbide. Office of Scientific and Technical Information (OSTI), September 1998. http://dx.doi.org/10.2172/330621.

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Ewing, R. C., and L. M. Wang. Particle-induced amorphization of complex ceramics. Final report. Office of Scientific and Technical Information (OSTI), August 1998. http://dx.doi.org/10.2172/639811.

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Snead, L. L., and S. J. Zinkle. Threshold irradiation dose for amorphization of silicon carbide. Office of Scientific and Technical Information (OSTI), April 1997. http://dx.doi.org/10.2172/543281.

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Snead, L. L., and S. J. Zinkle. Amorphization and the effect of implanted ions in SiC. Office of Scientific and Technical Information (OSTI), December 1994. http://dx.doi.org/10.2172/52826.

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Simpson, T. W., D. Love, E. Endisch, R. D. Goldberg, I. V. Mitchell, T. E. Haynes, and J. M. Baribeau. Amorphization threshold in Si-implanted strained SiGe alloy layers. Office of Scientific and Technical Information (OSTI), December 1994. http://dx.doi.org/10.2172/41378.

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Weber, W. J., and L. M. Wang. Temperature dependence of ion-beam-induced amorphization in {beta}-SiC. Office of Scientific and Technical Information (OSTI), February 1995. http://dx.doi.org/10.2172/10119438.

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Birtcher, R. C. Energy dependence of Ge amorphization by Ne, Ar or Kr ion irradiation. Office of Scientific and Technical Information (OSTI), October 1994. http://dx.doi.org/10.2172/436444.

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Zinkle, S. J., and L. L. Snead. Influence of irradiation spectrum and implanted ions on the amorphization of ceramics. Office of Scientific and Technical Information (OSTI), April 1996. http://dx.doi.org/10.2172/270452.

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Machavariani, G. Y., G. K. Rozenberg, M. P. Pasternak, O. Naaman, and R. D. Taylor. High pressure metallization and amorphization of the molecular crystal Sn(IBr){sub 2}. Office of Scientific and Technical Information (OSTI), December 1998. http://dx.doi.org/10.2172/304019.

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