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Journal articles on the topic 'Impurity distribution'

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Author: Grafiati

Published: 4 June 2021

Last updated: 31 January 2023

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1

Zhang, Xiao Wei, Rui Ying Miao, Jia Min Zhong, Zong An Li, Dao Gao Wu, De Hong Chen, and Zhi Qiang Wang. "Impurity Characterization by LA-ICP-MS in Terbium Metal after Solid State Electrotransport Purification." Key Engineering Materials 921 (May 30, 2022): 119–28. http://dx.doi.org/10.4028/p-965yg3.

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Terbium metal rod with the dimension of 6.8mm in diameter and 150mm in length has been purified by solid state electrotransport (SSE) at 1050°C under a pressure of 10-5Pa for 50h, and the impurity distribution has been determined by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The research results indicate that, the rare earth impurity migrates from cathode to anode of the rod, and the impurity distribution is relatively uniform in the longitudinal section; low melting point impurity of Al migrates from cathode to anode and the impurity concentration distribution is relatively uniform in the longitudinal section, the segregation degree is about 10% in each sample; the impurity with high melting point, Ta, W, Mo, etc., the distribution of above impurity is very non-uniform, for the impurity of Ta, the mean concentration of sample 7 is only 8.75 ppm, but the local concentration is up to 350 ppm, and it exists in an elementary substance form in the Tb; non-rare earth impurity in Tb metal, such as Ni, Si and Ti, migrates from cathode to anode of the rod significantly; the total impurity content in cathode end is lower than other posion, the impurty content of 22 imputies in sample 6 is 648.47 ppm, is the lowest in the Tb rod, except for the high melting point impurities, the lowest impurity content is 60.05ppm in sample 7.

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2

Wang, Li Hua, Qiu Yan Hao, Bing Zhang Wang, Wei Zhong Sun, and Cai Chi Liu. "Distribution of Carbon in Large Diameter Semi-Insulating Gallium Arsenide Grown by Liquid Encapsulated Czochralski Technique." Advanced Materials Research 472-475 (February 2012): 587–90. http://dx.doi.org/10.4028/www.scientific.net/amr.472-475.587.

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Carbon impurity concentration and dislocation density were investigated with optical microscopy and Fourier transform infrared absorption spectrometer in radial direction of large diameter (6-inch) undoped semi-insulating Gallium Arsenide (SI-GaAs) grown by liquid encapsulated Czochralski (LEC). The experimental results showed that their distributions are both “W”-shaped along wafer diameter, which is relatively higher on the center and lower near the center, but highest on the edge of the wafer. The nonuniformity distribution of thermal stress from growth process leads to the “W”-shaped distribution of dislocations in radial direction. The adsorption of matrix elastic strain field around dislocations induces the “W”-shaped distribution of carbon impurity. Dislocations adsorb carbon impurity and carbon impurity decorates dislocations. Dislocation density distribution affects carbon behavior.

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3

Bochegov, V. I., and A. S. Parakhin. "Limiting impurity distribution during zone refining." Technical Physics Letters 40, no. 6 (June 2014): 460–61. http://dx.doi.org/10.1134/s1063785014060029.

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4

Papirov, I. I., A. I. Kravchenko, A. I. Mazin, A. V. Shiyan, and V. D. Virich. "Impurity distribution in a magnesium sublimate." Inorganic Materials 51, no. 6 (May 6, 2015): 563–65. http://dx.doi.org/10.1134/s0020168515060126.

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5

Nepomnyashchikh, A. I., and R. V. Presnyakov. "Impurity Distribution in Multicrystalline Silicon Growth." Inorganic Materials 54, no. 4 (April 2018): 315–18. http://dx.doi.org/10.1134/s0020168518040106.

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6

Czajka, Katarzyna, and Maciej M. Maśka. "Impurity distribution in a frustrated system." Physica B: Condensed Matter 378-380 (May 2006): 275–77. http://dx.doi.org/10.1016/j.physb.2006.01.103.

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7

Hui, Meng-jun, Kirk Beatty, Katherine Blackmore, and Kenneth Jackson. "Impurity distribution in InSb single crystals." Journal of Crystal Growth 174, no. 1-4 (April 1997): 245–49. http://dx.doi.org/10.1016/s0022-0248(96)01112-8.

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8

Barnes, Piers R. F., and Eric W. Wolff. "Distribution of soluble impurities in cold glacial ice." Journal of Glaciology 50, no. 170 (2004): 311–24. http://dx.doi.org/10.3189/172756504781829918.

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AbstractUnderstanding the microstructure of ice underpins the interpretation of ice-core measurements and many ice-sheet properties. A detailed study of polar snow and ice using scanning electron microscope (SEM) and X-ray analysis revealed the micro-structural distribution of soluble impurities. Sublimation under vacuum (etching) concentrated impurity from both the bulk and grain boundaries on to the specimen surfaces in detectable quantities. Sublimation in the cold room before examination (pre-etching) collected previously unobservable quantities of impurity at triple junctions. A heterogeneous distribution of impurities was observed. Chloride was frequently found to originate from the lattice, but not usually at triple junctions. Other impurities, particularly sodium chloride, were detected at grain boundaries and bubble surfaces. Sulphate was often found at triple junctions in specimens containing a high bulk concentration of the acid, frequently in conjunction with cations. This suggests the possibility that veins were only filled with significant amounts of impurity when the surrounding grain boundaries were saturated. The model of impurity arrangement inferred from the results reconciles differences between previous SEM studies; additionally it is consistent with and explains recent electrical conduction observations. The disconnected arrangement of impurity-filled grain boundaries and veins limits opportunities for significant post-depositional solute movement.

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9

Wang, Yu, Yuan Peng Shou, and Yu Qiu. "Light Doping Effect on System Energy in Conjugated Polymers." Advanced Materials Research 590 (November 2012): 79–86. http://dx.doi.org/10.4028/www.scientific.net/amr.590.79.

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Based on a tight binding model, we investigate impurity effect upon the stability of neutral and negatively or positively charged 1D conjugated polymer chains. Impurities are introduced by an attractive or a repulsive potential located at the lattice sites. The offsets of system energy due to light doping are calculated within adiabatic approximation. We show that doping position has significant impact upon system stability. A general picture of impurity distribution along the stretch direction of the polymer chain is obtained for both attractive and repulsive impurity potentials in neutral as well as in charged conjugated polymers. A polymer chain can generally be divided into edge, center and transition regions in terms of impurity distribution. It is found the static impurity distribution within a polymer is dominated by the strength and the sign of the impurity potential as well as whether the polymer chain is neutral or charged. Impurity distribution within the edge and the transition region is characterized by cluster and that within the center region by separation.

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10

Skrobian, Milan, and Rudolf Pernis. "MATHEMATICAL EQUATION FOR IMPURITY DISTRIBUTION AFTER SECOND PASS OF ZONE REFINING." Acta Metallurgica Slovaca 27, no. 1 (February 25, 2021): 32–35. http://dx.doi.org/10.36547/ams.27.1.808.

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A mathematical equation has been derived that describes impurity distribution in ingot after second pass of zone refining. While an exponential impurity distribution is calculated by a simplified model after first pass, second pass is described by mixed linear - exponential model. Relationship of transformed impurity concentration is constant over whole length of semi-infinite ingot for first pass. However, it has linear trend for second pass. Last part of molten zone at infinity solidifies differently and can be described mathematically as directional crystallization. A mathematical tool devised for second pass of zone refining can be tried to be used for derivation of functions of more complex models that would describe impurity distribution in more realistic way compared to simplified approach. Such models could include non-constant distribution coefficient and/or shrinking or widening molten zone over a length of ingot.

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11

Selivanov, E. N., S. V. Sergeeva, A. A. Korolev, K. L. Timofeev, S. A. Krayukhin, and K. V. Pikulin. "Impurity Distribution During Electrolytic Refining of Antimony." Metallurgist 64, no. 11-12 (March 2021): 1198–207. http://dx.doi.org/10.1007/s11015-021-01105-0.

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12

Callahan, Daniel L., and Gareth Thomas. "Impurity Distribution in Polycrystalline Aluminum Nitride Ceramics." Journal of the American Ceramic Society 73, no. 7 (July 1990): 2167–70. http://dx.doi.org/10.1111/j.1151-2916.1990.tb05298.x.

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13

Kravchenko, A. I. "Equation of impurity distribution in solidified distillates." Inorganic Materials 43, no. 8 (August 2007): 916–17. http://dx.doi.org/10.1134/s0020168507080171.

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14

Kitada, Masahiro, and Hitoshi Nakamura. "Impurity distribution of very thin permalloy films." Thin Solid Films 167, no. 1-2 (December 1988): L39—L41. http://dx.doi.org/10.1016/0040-6090(88)90518-4.

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15

Nobis, Thomas, Evgeni M. Kaidashev, Andreas Rahm, Michael Lorenz, Jörg Lenzner, and Marius Grundmann. "Spatially Inhomogeneous Impurity Distribution in ZnO Micropillars." Nano Letters 4, no. 5 (May 2004): 797–800. http://dx.doi.org/10.1021/nl049889y.

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16

Gavin, L. B., and V. A. Naumov. "Distribution of disperse impurity in turbulent jet." Journal of Engineering Physics 49, no. 4 (October 1985): 1136–42. http://dx.doi.org/10.1007/bf00871906.

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17

Simons, Terrence J., Rohan L. de Silva, and Dennis E. Creasy. "Crystallisation of pentaerythritol. III. Impurity distribution coefficients." Journal of Chemical Technology and Biotechnology 32, no. 4 (April 24, 2007): 518–24. http://dx.doi.org/10.1002/jctb.5030320404.

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18

Chen, Dehong, Chuang Yu, Zhiqiang Wang, Xiaowei Zhang, Wenli Lu, and Dongwei Zhang. "Simulation of Lanthanum Purification Using a Finite Element Method." Materials 15, no. 9 (April 28, 2022): 3183. http://dx.doi.org/10.3390/ma15093183.

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The zone refining technology is considered to be one of the most effective means of purifying lanthanum. However, it is tough to obtain the temperature distribution of the molten region through experimental methods. In this study, finite element analysis was used to establish the zone refining simulation model, and the impurity distribution of lanthanum after purification was investigated experimentally. Good agreement between the simulated and experimental results was obtained. The effects of the current and the frequency on the temperature distribution and the width of the region were studied using the simulation model. Through the zone refining experiment, the impurity distributions under different widths of molten region were revealed. Finally, the influence of molten region width on the limiting distribution was calculated by solving the limiting distribution equation.

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19

Presnyakov, R. V., S. M. Peshcherova, A. G. Chueshova, V. A. Bychinskii, and A. I. Nepomnyashchikh. "Impurity-impurity interaction during the growth of UMG-Si-based mc-Si." Proceedings of Universities. Applied Chemistry and Biotechnology 12, no. 1 (April 1, 2022): 15–29. http://dx.doi.org/10.21285/2227-2925-2022-12-1-15-29.

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This article investigates the relationship between the chemical composition and electrophysical properties of p- and n-type multicrystalline silicon ingots based on metallurgical silicon with a purity of 99.99 at.%. In particular, the role of impurity-impurity interactions in the production of multisilicon by the Bridgman vertical method is evaluated in order to identify approaches to controlling this process effectively. The phase equilibrium calculations in the “silicon–all impurities” and “silicon-impurity-oxygen” systems were carried out based on the Gibbs energy minimization in the Selector software package. The study investigates the rank correlations of the concentrations of various impurities with each other, as well as with the specified electrical resistivity (SER) and the lifetime of nonequilibrium charge carriers (NCC) in the direction of crystal growth. Pair correlations of the element distribution profiles were considered based on the role of the main factor represented by the ratio of individual impurity solubilities in solid or liquid silicon (k0), as well as from the standpoint of direct interaction between two elements. It was found that the k0 value for two individual impurities in silicon does not automatically lead to the pair correlation of their distribution profiles in the ingot. A significant effect on the distribution profiles of impurities in multisilicon with k0→0 has the factor of binding some part of the impurity into such a form that this impurity can be incorporated easily into a growing crystal. Binding may be induced by the interaction of the impurity in the melt with the oxygen background, its segregation at the grain boundaries, and its capture by the crystallization front in the composition of the liquid inclusion. Significant correlations of impurity distribution profiles in the ingot were demonstrated by the pairs whose elements interact without the formation of chemical compounds in the 25–1413 °C temperature range. The conducted phase equilibrium calculations for the “silicon–all impurities” system revealed the possibility of forming the VB2, TiB2, ZrB2, and MgTiO4 solid phases in the melt.

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20

Cho, Jin Sang, Sung Min Joo, Sang Hwan Cho, Young Hwan Yu, Im Ho Kim, Hwan Kim, and Choon Han. "Change of Formation Yield and Characterization of PCC Particle Synthesized with Impurity Ions Contents by Carbonation Process." Materials Science Forum 510-511 (March 2006): 1026–29. http://dx.doi.org/10.4028/www.scientific.net/msf.510-511.1026.

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The effect of the impurity ions Al3+, Fe3+ and Mg2+ on the formation yield and crystal properties of precipitated calcium carbonate(PCC) produced by the carbonation process was investigated in Ca(OH)2-H2O-CO2 system. The effect of the impurity ions Al3+, Fe3+ and Mg2+ on the formation yield using particle size distribution and morphology of PCC were discussed. The particle size distribution of PCC was increased with increase of impurity ions. The morphology was transformed in order of spheroidal, scalenohedral, rhombohedral calcite for Al3+, Fe3+ and rhombospheroidal, spherical, scalenohedral for Mg2+ with increase of impurity ions.

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21

Shi, Shu Ang, Wei Dong, Shi Hai Sun, Yi Tan, Guo Bin Li, and Fu Min Xu. "Resistivity Distribution Characteristics of Metallurgical Silicon Ingot after Directional Solidification." Materials Science Forum 675-677 (February 2011): 109–12. http://dx.doi.org/10.4028/www.scientific.net/msf.675-677.109.

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The distribution of resistivity, impurity and polarity in multicrystalline silicon ingot prepared by directional solidification method was detected. The effect of impurity distribution on resistivity was also researched. The results show that the shapes of equivalence line of resistivity in the cross section and vertical section of the silicon ingot depend on the solid-liquid interface. The resistivity in the vertical section increases with the increasing of solidified height at the beginning of solidification and reaches to maximum at the polarity transition point, then decreases rapidly with the increasing of solidified height and tends to zero on the top of the ingot because of the high impurity concentration. Study proves that the variation of resistivity in the vertical section is mainly relevant to the concentration distribution of the impurities such as Al, B and P in the growth direction.

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22

Zainabidinov, S. Z., N. A. Turgunov, Sh K. Akbarov, E. Kh Berkinov, and D. Kh Mamazhonova. "DISTRIBUTION OF IMPURITY ATOMS BY THE VOLUME OF MICROINCUTIONS IN SAMPLES n-Si <Ni>." SEMOCONDUCTOR PHYSICS AND MICROELECTRONICS 3, no. 1 (February 28, 2021): 10–15. http://dx.doi.org/10.37681/2181-1652-019-x-2021-1-1.

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The paper considers the structural structure o f nickel impurity microinclusions in silicon, form ed during diffusion alloying at a temperature o f T = 1523 K. Using microprobe analysis, images o f nickel impurity microinclusions were obtained, and their chemical compositions were determined. The distribution o f Ni atoms and some technological impurities such as Fe and Cr over the volume o f multilayer microinclusions was revealed, according to which the maximum percentage o f impurity atoms is in its central part.

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23

Lopatina, Oksana V., Leonid A. Svyatkin, Yury M. Koroteev, and Ivan P. Chernov. "Features of Valence Electron Density Distribution in Zr–H and Zr–He." Advanced Materials Research 1084 (January 2015): 241–45. http://dx.doi.org/10.4028/www.scientific.net/amr.1084.241.

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Ab initio calculations of electronic structures of Zr–H and Zr–He systems have been done. The influence of hydrogen or helium impurities on the electron density distribution of the host metal has been considered. Extremely inhomogeneous redistribution of the metal valence charge density within the first coordination sphere of the impurity was found. The character of the observed anisotropy depends on the impurity type.

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24

Sidoryakina, Valentina V., and Sofya V. Protsenko. "The dynamics of impurity distribution in marine systems." MATEC Web of Conferences 226 (2018): 04026. http://dx.doi.org/10.1051/matecconf/201822604026.

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The system of Navier-Stokes equations, which includes three equations of motion in regions with a dynamically varying geometry of the computational domain was used to describe the wave processes. The velocity vector field is used as input information for calculating the dynamics of impurity propagation in marine systems. The article considers construction and investigation of parallel algorithms for the numerical realization of 3D models of suspended matter transportation and deposition and 2D models of bottom sediment transportation in sea coastal systems on the basis of explicit schemes with regularization terms that provide improved stability quality. The developed models take into account coastal currents and stress near the bottom caused by wind waves, turbulent spatial-three-dimensional motion of the water medium, particle size distribution and porosity of bottom sediments and hydraulic size of suspended particles, complicated shoreline shape and bottom relief and other factors. The practical significance of numerical algorithms and the complex of programs that realize them consists in the possibility of their application in the study of processes in coastal water systems, as well as in constructing the velocity and pressure field of the aquatic environment.

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25

Shvydkii, E. L., S. A. Bychkov, V. V. Zakharov, I. V. Sokolov, and F. E. Tarasov. "Impurity Distribution in a Two-Sided Electromagnetic Stirrer." Russian Metallurgy (Metally) 2019, no. 6 (June 2019): 570–75. http://dx.doi.org/10.1134/s0036029519060156.

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26

ZHANG, Xiaowei, Ruiying MIAO, Chuanjun LI, Daogao WU, Huan YAN, Zhiqiang WANG, Dehong CHEN, Shihong YAN, and Zongan LI. "Impurity distribution in metallic dysprosium during distillation purification." Journal of Rare Earths 34, no. 9 (September 2016): 924–30. http://dx.doi.org/10.1016/s1002-0721(16)60116-3.

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27

Shut, V. N., I. F. Kashevich, and B. E. Watts. "Water-soluble ferroelectric crystals with inhomogeneous impurity distribution." Crystallography Reports 49, no. 2 (March 2004): 206–10. http://dx.doi.org/10.1134/1.1690417.

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28

Ostanin, N. I., V. M. Rudoy, I. P. Demin, T. N. Ostanina, and V. S. Nikitin. "Statistical analysis of the distribution of impurities during copper electrorefining." Izvestiya Vuzov. Tsvetnaya Metallurgiya (Universities' Proceedings Non-Ferrous Metallurgy), no. 4 (August 12, 2021): 16–23. http://dx.doi.org/10.17073/0021-3438-2021-4-16-23.

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Electrolytic copper refining makes it possible to obtain high purity metal, so the analysis of the main ways of impurity transition into electrolysis products is an actual problem. If it is solved, the process can be controlled when changing the composition of raw materials and, as a result, the content of impurities in the anodes. This paper uses the comprehensive analysis and synchronization of a large array of data on impurities concentrations in various process media (anodes, electrolyte, slime, and cathode metal) obtained on the series of commercial cells to identify the directions of impurity flows and relationship between their content in these media. It is shown that the transition of impurities from one process medium (source) to another (receiver) is implemented according to four main patterns: linear increase, no visible dependence, the presence of a limit concentration in the receiver and the presence of a threshold concentration in the source. The paper provides the results obtained in the statistical analysis of the distribution of six impurities (bismuth, arsenic, lead, sulfur, nickel and silver) belonging to different groups in four main pairs of the impurity source – receiver: anode – solution, anode – slime, slime – cathode, solution – cathode. The coefficients of linear regression equations are determined and their significance is estimated for all dependencies of the impurity concentration in the source on the content in the receiver. The coefficients obtained make it possible to explain the impurity transition paths observed in the commercial cells and predict the quality of cathode copper and the composition of slimes when the anode composition changes. The calculations showed that impurities are accumulated in cathodes due to the occlusion of slime particles and incomplete solution removal from the surface of commercial cathodes rather than due to electrochemical reactions. The copper electrorefining technology should be improved and developed so as to find surface-active additives that would prevent the adsorption of suspended slime particles on the cathode surface, as well as better wash them from the electrolyte.

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29

Velichko, O. I. "On concentration dependence of arsenic diffusivity in silicon." International Journal of Computational Materials Science and Engineering 05, no. 01 (March 2016): 1650005. http://dx.doi.org/10.1142/s2047684116500056.

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An analysis of the equations used for modeling thermal arsenic diffusion in silicon has been carried out. It was shown that for arsenic diffusion governed by the vacancy-impurity pairs and the pairs formed due to interaction of impurity atoms with silicon self-interstitials in a neutral charge state, the doping process can be described by the Fick’s second law equation with a single effective diffusion coefficient which takes into account two impurity flows arising due to interaction of arsenic atoms with vacancies and silicon self-interstitials, respectively. Arsenic concentration profiles calculated with the use of the effective diffusivity agree well with experimental data if the maximal impurity concentration is near the intrinsic carrier concentration. On the other hand, for higher impurity concentrations a certain deviation in the local regions of arsenic distribution is observed. The difference from the experiment can occur due to the incorrect use of effective diffusivity for the description of two different impurity flows or due to the formation of nonuniform distributions of neutral vacancies and neutral self-interstitials in heavily doped silicon layers. We also suppose that the migration of nonequilibrium arsenic interstitial atoms makes a significant contribution to the formation of a low concentration region on thermal arsenic diffusion.

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30

Barraud, S., P. Dollfus, S. Galdin, R. Rengel, M. J. Martin, and J. E. Velázquez. "An lonised-impurity Scattering Model for 3D Monte Carlo Device Simulation with Discrete Impurity Distribution." VLSI Design 13, no. 1-4 (January 1, 2001): 399–404. http://dx.doi.org/10.1155/2001/96951.

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An improved 3-D Monte Carlo simulation model is developed to treat the discrete random dopant distribution in sub-0.1 μm MOSFET. The new atomistic model is based on a scattering rate calculation and an algorithm that take into account many-body effects and the local variations of screening length according to impurity distribution and bias conditions.To validate this new approach low field electron drift mobility and diffusion coefficient have been computed using simulation of 3D bars for 1015–1018 cm–3 range of average doping concentration. A good agreement is found between calculation and experimental mobility data at 300 K.

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31

HUANG, HAI, and JIANGHUA LI. "THE ABSORPTION AND CONDUCTIVITY FOR MICROSTRUCTURED SILICON IN THE IMPURITY-DEFECT MODEL." Modern Physics Letters B 27, no. 16 (June 6, 2013): 1350116. http://dx.doi.org/10.1142/s0217984913501169.

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In this paper, a model for the optical absorption and carrier concentration in microstructured silicon is presented based on Gaussian energy distribution of defect and impurity, as well as the Boltzmann distribution of carriers. The parameters of the impurity and defect model contributing to the absorption and carrier concentration are investigated. The simulation results show that the absorption in the single level impurity-defect model ranges from 64% to 68%; larger than that in the single level impurity model (55%–65%); as well as that in the defect model (50%–66%). It also indicates that the absorption increases with bigger correlation energy (U) and the best bandwidth (d) is 0.92 eV. However, the carrier concentration gets stronger with bigger bandwidth, smaller correlation energy and higher temperature. Thus, these calculations would play an important role in the applications of microstructured silicon.

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32

Inglot, Michał, and Tomasz Szczepański. "Impurity-Induced Magnetization of Graphene." Materials 15, no. 2 (January 11, 2022): 526. http://dx.doi.org/10.3390/ma15020526.

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We present a model of impurity-induced magnetization of graphene assuming that the main source of graphene magnetization is related to impurity states with a localized spin. The analysis of solutions of the Schrödinger equation for electrons near the Dirac point has been performed using the model of massless fermions. For a single impurity, the solution of Schrödinger’s equation is a linear combination of Bessel functions. We found resonance energy levels of the non-magnetic impurity. The magnetic moment of impurity with a localized spin was accounted for the calculation of graphene magnetization using the Green’s function formalism. The spatial distribution of induced magnetization for a single impurity is obtained. The energy of resonance states was also calculated as a function of interaction. This energy is depending on the impurity potential and the coupling constant of interaction.

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33

Baroni, Travis C., Brendan J. Griffin, James R. Browne, and Frank J. Lincoln. "Correlation between Charge Contrast Imaging and the Distribution of Some Trace Level Impurities in Gibbsite." Microscopy and Microanalysis 6, no. 1 (January 2000): 49–58. http://dx.doi.org/10.1017/s1431927600000088.

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Charge contrast images (CCI) of synthetic gibbsite obtained on an environmental scanning electron microscope gives information on the crystallization process. Furthermore, X-ray mapping of the same grains shows that impurities are localized during the initial stages of growth and that the resulting composition images have features similar to these observed in CCI. This suggests a possible correlation between impurity distributions and the emission detected during CCI. X-ray line profiles, simulating the spatial distribution of impurities derived from the Monte Carlo program CASINO, have been compared with experimental line profiles and give an estimate of the localization. The model suggests that a main impurity, Ca, is depleted from the solution within approximately 3–4 μm of growth.

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34

Baroni, Travis C., Brendan J. Griffin, James R. Browne, and Frank J. Lincoln. "Correlation between Charge Contrast Imaging and the Distribution of Some Trace Level Impurities in Gibbsite." Microscopy and Microanalysis 6, no. 1 (January 2000): 49–58. http://dx.doi.org/10.1007/s100059910005.

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Abstract Charge contrast images (CCI) of synthetic gibbsite obtained on an environmental scanning electron microscope gives information on the crystallization process. Furthermore, X-ray mapping of the same grains shows that impurities are localized during the initial stages of growth and that the resulting composition images have features similar to these observed in CCI. This suggests a possible correlation between impurity distributions and the emission detected during CCI. X-ray line profiles, simulating the spatial distribution of impurities derived from the Monte Carlo program CASINO, have been compared with experimental line profiles and give an estimate of the localization. The model suggests that a main impurity, Ca, is depleted from the solution within approximately 3–4 μm of growth.

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35

E SILVA, E. A. DE ANDRADA, and I. C. DA CUNHA LIMA. "DENSITY OF STATES AND CHARGE DISTRIBUTION IN LIGHTLY DOPED AND COMPENSATED QUANTUM WELL." Modern Physics Letters B 03, no. 11 (July 20, 1989): 815–19. http://dx.doi.org/10.1142/s021798498900128x.

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In this letter we use a Semi-Classical Impurity Band Model and obtain by Monte Carlo simulation the density of states (DOS) and the impurity charge distribution inside a quantum well (QW) of Ga 1−x Al x As/GaAs . We show the existence of a Coulomb gap as has been observed in bulk semiconductors. The DOS is not very sensitive to the QW width close to the Coulomb gap, at least in the range from 1 to 4 times the Bohr radius, and shows a behavior D(E)∝|E−EF| which indicates a two-dimensional signature. We show that the neutral donors concentrate in the center of the well according to a distribution whose width and decay rate depend on the compensation and impurity concentration respectively. Those effects are expected to be observed by infra-red absorption experiments and useful in device diagnosis.

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36

Callahan, Daniel, and G. Thomas. "CBED analysis of impurity distributions in AlN." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 214–15. http://dx.doi.org/10.1017/s0424820100174205.

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Oxygen impurities may significantly influence the properties of nitride ceramics with a strong dependence on the microstructural distribution of the impurity. For example, amorphous oxygen-rich grain boundary phases are well-known to cause high-temperature mechanical strength degradation in silicon nitride whereas solutionized oxygen is known to decrease the thermal conductivity of aluminum nitride. Microanalytical characterization of these impurities by spectral methods in the AEM is complicated by reactions which form oxygen-rich surface phases not representative of the bulk material. Furthermore, the impurity concentrations found in higher quality ceramics may be too low to measure by EDS or PEELS. Consequently an alternate method for the characterization of impurities in these ceramics has been investigated.Convergent beam electron diffraction (CBED) is a promising technique for the study of impurity distributions in aluminum nitride ceramics. Oxygen is known to enter into stoichiometric solutions with AIN with a consequent decrease in lattice parameter.

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37

Гайнутдинов, Р. В., А. Л. Толстихина, А. К. Лашкова, Н. В. Белугина, В. Н. Шут, С. Е. Мозжаров, and И. Ф. Кашевич. "Применение сканирующей емкостной силовой микроскопии для выявления примесных фаз в сегнетоэлектрике триглицинсульфат." Журнал технической физики 89, no. 11 (2019): 1692. http://dx.doi.org/10.21883/jtf.2019.11.48330.119-19.

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The results of the study of inhomogeneous ferroelectric triglycine sulfate single crystal with a growth periodic impurity structure TGS - TGS + Cr are presented. The impurity distribution was investigated with scanning capacitance force microscopy (SCFM). The peculiarities of the capacitance variations imaging on a doubled and tripled resonant frequency of electrostatic force are considered. The piezoelectric response, surface potential and surface topography were studied. It is shown that capacitive contrast is formed both at the domain boundaries and in the TGS and TGS + Cr bands. It was shown that SCFM allowed one to observe the impurity spatial distribution in the ferroelectric structure at the difference in the chromium concentration about 0.02-0.08 wt%.

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Morozova, Ekaterina, and Vladimir Panov. "Extreme Value Analysis for Mixture Models with Heavy-Tailed Impurity." Mathematics 9, no. 18 (September 9, 2021): 2208. http://dx.doi.org/10.3390/math9182208.

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This paper deals with the extreme value analysis for the triangular arrays which appear when some parameters of the mixture model vary as the number of observations grows. When the mixing parameter is small, it is natural to associate one of the components with “an impurity” (in the case of regularly varying distribution, “heavy-tailed impurity”), which “pollutes” another component. We show that the set of possible limit distributions is much more diverse than in the classical Fisher–Tippett–Gnedenko theorem, and provide the numerical examples showing the efficiency of the proposed model for studying the maximal values of the stock returns.

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Yokoi, Toru, Motoshige Yumoto, and Takao Sakai. "Secondary Electron Energy Distribution from Electrode Surface with Impurity." IEEJ Transactions on Fundamentals and Materials 115, no. 9 (1995): 912–13. http://dx.doi.org/10.1541/ieejfms1990.115.9_912.

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Vykhodets, V. B., Tatiana Eugenievna Kurennykh, and N. U. Tarenkova. "Study of Distribution of Impurity Atoms in Metallurgical Macrodefects." Defect and Diffusion Forum 273-276 (February 2008): 707–12. http://dx.doi.org/10.4028/www.scientific.net/ddf.273-276.707.

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Using nuclear microanalysis (NRA) and electron probe microanalysis (EPMA), concentrations of carbon, oxygen, nitrogen, aluminum, and vanadium were measured on a large group of macrodefects formed in the course of smelting titanium alloys. A remarkable enrichment of the defect material in oxygen and nitrogen atoms was detected; histograms of defect distribution over the concentrations of oxygen, nitrogen, aluminum, and vanadium were obtained. The above results agree with the concepts according to which the defects are formed from the particles that have the melting temperature higher then the temperature of smelting.

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Volkov, P. K., B. G. Zakharov, and Yu A. Serebryakov. "Convection in melts and impurity distribution in semiconductor crystals." Crystallography Reports 45, no. 5 (September 2000): 862–70. http://dx.doi.org/10.1134/1.1312937.

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Abdrashitov, V. G., and V. V. Ryzhov. "Modeling of the impurity distribution obtained by ion implantation." Russian Physics Journal 37, no. 5 (May 1994): 410–22. http://dx.doi.org/10.1007/bf00560112.

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Hou, P. Y., X. F. Zhang, and R. M. Cannon. "Impurity distribution in Al2O3 formed on an FeCrAl alloy." Scripta Materialia 50, no. 1 (January 2004): 45–49. http://dx.doi.org/10.1016/j.scriptamat.2003.09.044.

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Al-Omari, A. K., R. Reininger, and D. L. Huber. "Polarization energy distribution for impurity molecules in dense gases." Journal of Chemical Physics 109, no. 18 (November 8, 1998): 7663–66. http://dx.doi.org/10.1063/1.477412.

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Bâldea, Ioan, and Marian Bădescu. "Quasiregular impurity distribution driven by a charge-density wave." Physical Review B 48, no. 12 (September 15, 1993): 8619–28. http://dx.doi.org/10.1103/physrevb.48.8619.

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Kundrotas, J., A. Dargys, and A. Cesna. "The hot electron distribution function under impurity breakdown conditions." physica status solidi (b) 194, no. 2 (April 1, 1996): 649–60. http://dx.doi.org/10.1002/pssb.2221940220.

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Bohleber, Pascal, Marco Roman, Martin Šala, and Carlo Barbante. "Imaging the impurity distribution in glacier ice cores with LA-ICP-MS." Journal of Analytical Atomic Spectrometry 35, no. 10 (2020): 2204–12. http://dx.doi.org/10.1039/d0ja00170h.

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48

Dai, S. Y., D. F. Kong, V. S. Chan, L. Wang, Y. Feng, and D. Z. Wang. "EMC3–EIRENE simulations of neon impurity seeding effects on heat flux distribution on CFETR." Nuclear Fusion 62, no. 3 (March 1, 2022): 036019. http://dx.doi.org/10.1088/1741-4326/ac47b5.

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Abstract The numerical modelling of the heat flux distribution with neon impurity seeding on China fusion engineering test reactor has been performed by the three-dimensional (3D) edge transport code EMC3–EIRENE. The maximum heat flux on divertor targets is about 18 MW m−2 without impurity seeding under the input power of 200 MW entering into the scrape-off layer. In order to mitigate the heat loads below 10 MW m−2, neon impurity seeded at different poloidal positions has been investigated to understand the properties of impurity concentration and heat load distributions for a single toroidal injection location. The majority of the studied neon injections gives rise to a toroidally asymmetric profile of heat load deposition on the in- or out-board divertor targets. The heat loads cannot be reduced below 10 MW m−2 along the whole torus for a single toroidal injection location. In order to achieve the heat load mitigation (<10 MW m−2) along the entire torus, modelling of sole and simultaneous multi-toroidal neon injections near the in- and out-board strike points has been stimulated, which indicates that the simultaneous multi-toroidal neon injections show a better heat flux mitigation on both in- and out-board divertor targets. The maximum heat flux can be reduced below 7 MW m−2 on divertor targets for the studied scenarios of the simultaneous multi-toroidal neon injections.

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REKHA, B., and K. NAVANEETHAKRISHNAN. "CARRIER MOBILITY IN A SEMICONDUCTOR QUANTUM WELL WIRE–EFFECTS OF EXTERNAL PERTURBATIONS." International Journal of Modern Physics B 20, no. 01 (January 10, 2006): 49–60. http://dx.doi.org/10.1142/s0217979206033048.

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Carrier mobility in a narrow GaAs semiconductor quantum well wire embedded in the GaAlAs matrix is investigated using a simple model developed by Lee and Spector. Five different screening functions with three different impurity distributions are used in the calculations. The results show that (i) the choice of the screening function is important as the mobility values vary by two orders of magnitude, and (ii) the mobility values not only depend on the impurity distribution but also vary differently with the wire radius. While hydrostatic pressure reduces the mobility values, temperature increases the values. The polaronic effect decreases the mobility values irrespective of temperature and pressure, the maximum contribution being 9%.

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Lai, Hui Xian, Liu Qing Huang, Ming Fang, Cheng Hao Lu, Juan Chen, De Qin Yu, Jin Tang Li, Wen Hui Ma, Jian Ning Shen, and Xue Tao Luo. "Precipitation Phase and Impurities Distribution of Metallurgical Grade Silicon by Vacuum Refining Followed Slag Treatment." Advanced Materials Research 813 (September 2013): 492–96. http://dx.doi.org/10.4028/www.scientific.net/amr.813.492.

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Precipitation phase and impurities distribution of MG-silicon were investigated by vacuum refining followed by slag treatment, and the CaO-SiO2-CaF2 system was adopted for slag treatment. Contrasting the microstructure of precipitated phase in slag treatment with and without vacuum refining pretreated, it could be concluded that the composition of precipitated phases, obtained in MG-Si after vacuum refining followed slag treatment, only consisted of Ca-rich intermetallic silicide phases such as Si-Ca-Ni, Si-Ca-Fe and main impurity phase Si-Ca. And the vacuum refining could make an increase in concentration of the impurity Ti due to its low saturated vapor pressure and silicon loss, which was in favor of the interaction with the impurity B, resulting in the formation of TiB2 that could stay at the slag. Consequently, the vacuum refining could be regarded as an effective method for facilitating the removal of B from MG-Si with slag treatment.

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