Artículos de revistas: "II-VI Substrates"

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Sato, K., Y. Seki, Y. Matsuda y O. Oda. "Recent developments in II–VI substrates". Journal of Crystal Growth 197, n.º 3 (febrero de 1999): 413–22. http://dx.doi.org/10.1016/s0022-0248(98)00739-8.

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2

Ernst, K., I. Sieber, M. Neumann-Spallart, M. Ch Lux-Steiner y R. Könenkamp. "Characterization of II–VI compounds on porous substrates". Thin Solid Films 361-362 (febrero de 2000): 213–17. http://dx.doi.org/10.1016/s0040-6090(99)00836-6.

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Jones, K. M., F. S. Hasoon, A. B. Swartzlander, M. M. Al-Jassim, T. L. Chu y S. S. Chu. "The morphology and microstructure of polycrystalline CdTe thin films for solar cell applications". Proceedings, annual meeting, Electron Microscopy Society of America 50, n.º 2 (agosto de 1992): 1384–85. http://dx.doi.org/10.1017/s0424820100131553.

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Polycrystalline thin films of II-VI semiconductors on foreign polycrystalline (or amorphous) substrates have many applications in optoelectronic devices. In contrast to the extensive studies of the heteroepitaxial growth of compound semiconductors on single-crystal substrates, the nucleation and growth of thin films of II-VI compounds on foreign substrates have received little attention, and the properties of these films are often controlled empirically to optimize device performance. A better understanding of the nucleation, growth, and microstructure will facilitate a better control of the structural and electrical properties of polycrystalline semiconductor films, thereby improving the device characteristics. Cadmium telluride (CdTe) has long been recognized as a promising thin-film photovoltaic material. Under NREL's sponsorship, the University of South Florida has recently developed a record high efficiency (14.6% under global AM1.5 conditions) thin-film CdS/CdTe heterojunction solar cell for potential low-cost photovoltaic applications. The solar cell has the structure:glass (substrate)/SnO2:F/CdS/CdTe/HgTe (contact)The CdS films were grown from an aqueous solution, while the CdTe films were deposited by the closespaced sublimation method.

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ZAHN, DIETRICH R. T. "PROBING SURFACES AND INTERFACES WITH OPTICAL TECHNIQUES". Surface Review and Letters 01, n.º 04 (diciembre de 1994): 421–28. http://dx.doi.org/10.1142/s0218625x94000382.

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The potential of optical techniques for probing semiconductor surfaces and interfaces is discussed using the example of Raman spectroscopy. The surface sensitivity of the technique is demonstrated by the detection of vibrational modes of atomic monolayers on semiconductor substrates, for instance arsenic on silicon(111). The special feature of Raman spectroscopy, namely its chemical sensivity, is illustrated by two examples: the interdiffusion of group III overlayers, e.g., In on the group V substrate Sb and the detection of reacted layers at II–VI/III– V heterointerfaces. The example of II–VI/III–V heteroepitaxy also serves as an example for demonstrating the growth monitoring capabilities of optical techniques.

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5

Belyaev, A. P. y V. P. Rubets. "Heteroepitaxy of II-VI compound semiconductors on cooled substrates". Semiconductors 35, n.º 3 (marzo de 2001): 279–82. http://dx.doi.org/10.1134/1.1356146.

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6

Boney, C. "II–VI blue/green laser diodes on ZnSe substrates". Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures 14, n.º 3 (mayo de 1996): 2259. http://dx.doi.org/10.1116/1.588914.

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Cywiński, G., T. Wojtowicz, K. Kopalko, G. Karczewski y J. Kossut. "Epitaxial Growths of II-VI Compounds on (110) Substrates". Acta Physica Polonica A 94, n.º 2 (agosto de 1998): 281–84. http://dx.doi.org/10.12693/aphyspola.94.281.

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8

Thompson, J., K. T. Woodhouse y C. Dineen. "Epitaxial growth of II–VI compounds on sapphire substrates". Journal of Crystal Growth 77, n.º 1-3 (septiembre de 1986): 452–59. http://dx.doi.org/10.1016/0022-0248(86)90336-2.

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9

Schikora, D., H. Hausleitner, S. Einfeldt, C. R. Becker, Th Widmer, C. Giftge, K. Lübke, K. Lischka, M. von Ortenberg y G. Landwehr. "Epitaxial overgrowth of II–VI compounds on patterned substrates". Journal of Crystal Growth 138, n.º 1-4 (abril de 1994): 8–13. http://dx.doi.org/10.1016/0022-0248(94)90772-2.

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10

Brill, Gregory N., Yuanping Chen, Priyalal S. Wijewarnasuriya y Nibir K. Dhar. "Hg based II-VI compounds on non-standard substrates". physica status solidi (a) 209, n.º 8 (20 de junio de 2012): 1423–27. http://dx.doi.org/10.1002/pssa.201100734.

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Naugle, Jennifer E., Erik R. Olson, Xiaojin Zhang, Sharon E. Mase, Charles F. Pilati, Michael B. Maron, Hans G. Folkesson, Walter I. Horne, Kathleen J. Doane y J. Gary Meszaros. "Type VI collagen induces cardiac myofibroblast differentiation: implications for postinfarction remodeling". American Journal of Physiology-Heart and Circulatory Physiology 290, n.º 1 (enero de 2006): H323—H330. http://dx.doi.org/10.1152/ajpheart.00321.2005.

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Cardiac fibroblast (CF) proliferation and differentiation into hypersecretory myofibroblasts can lead to excessive extracellular matrix (ECM) production and cardiac fibrosis. In turn, the ECM produced can potentially activate CFs via distinct feedback mechanisms. To assess how specific ECM components influence CF activation, isolated CFs were plated on specific collagen substrates (type I, III, and VI collagens) before functional assays were carried out. The type VI collagen substrate potently induced myofibroblast differentiation but had little effect on CF proliferation. Conversely, the type I and III collagen substrates did not affect differentiation but caused significant induction of proliferation (type I, 240.7 ± 10.3%, and type III, 271.7 ± 21.8% of basal). Type I collagen activated ERK1/2, whereas type III collagen did not. Treatment of CFs with angiotensin II, a potent mitogen of CFs, enhanced the growth observed on types I and III collagen but not on the type VI collagen substrate. Using an in vivo model of myocardial infarction (MI), we measured changes in type VI collagen expression and myofibroblast differentiation after post-MI remodeling. Concurrent elevations in type VI collagen and myofibroblast content were evident in the infarcted myocardium 20-wk post-MI. Overall, types I and III collagen stimulate CF proliferation, whereas type VI collagen plays a potentially novel role in cardiac remodeling through facilitation of myofibroblast differentiation.

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12

Brockhausen, Inka, Jeremy P. Carver y Harry Schachter. "Control of glycoprotein synthesis. The use of oligosaccharide substrates and HPLC to study the sequential pathway for N-acetylglucosaminyltransferases I, II, III, IV, V, and VI in the biosynthesis of highly branched N-glycans by hen oviduct membranes". Biochemistry and Cell Biology 66, n.º 10 (1 de octubre de 1988): 1134–51. http://dx.doi.org/10.1139/o88-131.

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Glycoproteins isolated from hen oviduct contain highly branched asparagine-linked oligosaccharides (N-glycans). Six N-acetylglucosaminyltransferases (GlcNAc-T I, II, III, IV, V, and VI) are involved in initiating the synthesis of these branches, as indicated below:[Formula: see text]where R is GlcNAcβ1—4(+/−Fucα1—6)GlcNAcAsn-X. HPLC has been used to study the substrate specificities of these GlcNAc-T and the sequential pathways involved in the biosynthesis of highly branched N-glycans in hen oviduct. Oligosaccharides with free reducing GlcNAc termini were prepared from various glycoproteins by hydrazinolysis–re-N-acetylation and used as GlcNAc-T substrates and HPLC standards. Enzyme assay components were separated on AG1 × 8, followed by HPLC on amine-bonded silica columns eluted with acetonitrile–water mixtures. Absorbance at 195 nm and radioactivity of eluted compounds were monitored. Substrates and products were identified by comparison of their retention times with those of oligosaccharides with known structures. Enzyme assay by HPLC is more rapid and convenient than previous GlcNAc-T assays using lectin columns or electrophoresis. Since some substrates yielded multiple products, these could be used to assay more than one GlcNAc-T in the same incubation. GlcNAc-T VI was shown to act on both bisected and nonbisected GlcNAc-terminating tetraantennary oligosaccharide substrates; GlcNAc-T II, IV, and V acted poorly or not at all on bisected substrates. GlcNAc-T V was the only enzyme among the six transferases studied that could be assayed in the absence of Mn2+.

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13

Gupta, Avinash K., Ilya Zwieback, Andrew E. Souzis, Murugesu Yoganathan y Thomas Anderson. "Status of Large Diameter SiC Single Crystals at II-VI". Materials Science Forum 600-603 (septiembre de 2008): 35–38. http://dx.doi.org/10.4028/www.scientific.net/msf.600-603.35.

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II-VI is developing large-diameter SiC crystals to be used as lattice-matched, high thermal conductivity substrates for new generation GaN-based and SiC-based semiconductor devices. Large-diameter 6H SiC single crystals are grown at II-VI using our Advanced PVT sublimation growth process. Stable SI properties are achieved by compensation with vanadium, which results in high and spatially uniform resistivity, on the order of 1011 Ohm-cm. The quality of the presently grown 100 mm 6H SI substrates has been dramatically improved [1], and they are free of edge defects. Micropipe density in the 100 mm 6H SI substrates ranges from 2 to 8 cm-2 and dislocation density from 3·104 to 6·104 cm-2. X-ray rocking curves measured on as-sawn 100 mm 6H wafers showed edge-to-edge lattice curvature () between 0.1° and 0.3° and FWHM of the rocking curve between 50 and 100 arc-seconds

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14

Suarez, Ernesto, Pik-Yiu Chan, Mukesh Gogna, John E. Ayers, Evan Heller y Faquir Jain. "ZNS/ZNMGSETE/ZNS II-VI Energy Barrier for INGAAS Substrates". International Journal of High Speed Electronics and Systems 23, n.º 01n02 (marzo de 2014): 1450013. http://dx.doi.org/10.1142/s012915641450013x.

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InGaAs high mobility transistors presently provide the fastest speeds. As InGaAs nonvolatile memory field effect transistors (NVMFETs) are scaled down past 22 nm gate width, threshold voltage variation becomes a limiting factor. Replacing the amorphous SiO 2 or HfO 2 with a heteroepitaxial barrier stack the threshold voltage can be stabilized by minimizing the interface charge at the barrier-channel interface. The floating gate is comprised of individually germanium-oxide cladded germanium quantum dots. The tunneling layer is comprised of a quantum well stack of ZnSe / ZnS / ZnMgSeTe / ZnS / ZnSe . The magnesium incorporation increases the the energy barrier but introduces dislocation that can leak charge. The ZnS and ZnSe layers have a lower bandgap but a lower dislocation density to assist with gate leakage prevention. We present simulation and experimental C-V data on InGaAs FET and II-VI tunneling layer on an InGaAs substrate respectively.

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15

Bieker, S., P. R. Hartmann, T. Kießling, M. Rüth, C. Schumacher, C. Gould, W. Ossau y L. W. Molenkamp. "Removal of GaAs growth substrates from II–VI semiconductor heterostructures". Semiconductor Science and Technology 29, n.º 4 (26 de febrero de 2014): 045016. http://dx.doi.org/10.1088/0268-1242/29/4/045016.

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16

Wang, Jiawei, Jiahui Li, Yi Hou, Wei Dai, Ruopeng Xie, Tatiana T. Marquez-Lago, André Leier et al. "BastionHub: a universal platform for integrating and analyzing substrates secreted by Gram-negative bacteria". Nucleic Acids Research 49, n.º D1 (21 de octubre de 2020): D651—D659. http://dx.doi.org/10.1093/nar/gkaa899.

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Abstract Gram-negative bacteria utilize secretion systems to export substrates into their surrounding environment or directly into neighboring cells. These substrates are proteins that function to promote bacterial survival: by facilitating nutrient collection, disabling competitor species or, for pathogens, to disable host defenses. Following a rapid development of computational techniques, a growing number of substrates have been discovered and subsequently validated by wet lab experiments. To date, several online databases have been developed to catalogue these substrates but they have limited user options for in-depth analysis, and typically focus on a single type of secreted substrate. We therefore developed a universal platform, BastionHub, that incorporates extensive functional modules to facilitate substrate analysis and integrates the five major Gram-negative secreted substrate types (i.e. from types I–IV and VI secretion systems). To our knowledge, BastionHub is not only the most comprehensive online database available, it is also the first to incorporate substrates secreted by type I or type II secretion systems. By providing the most up-to-date details of secreted substrates and state-of-the-art prediction and visualized relationship analysis tools, BastionHub will be an important platform that can assist biologists in uncovering novel substrates and formulating new hypotheses. BastionHub is freely available at http://bastionhub.erc.monash.edu/.

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17

KERN, András, Zsófia SZENTPÉTERY, Károly LILIOM, Éva BAKOS, Balázs SARKADI y András VÁRADI. "Nucleotides and transported substrates modulate different steps of the ATPase catalytic cycle of MRP1 multidrug transporter". Biochemical Journal 380, n.º 2 (1 de junio de 2004): 549–60. http://dx.doi.org/10.1042/bj20031607.

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The human ABC (ATP-binding cassette) transporter MRP1 (human multidrug-resistance-associated protein 1; ABCC1) is involved in the cellular extrusion of conjugated metabolites and causes multidrug resistance in tumour cells. The transport of substrate molecules by ABC proteins is energized by ATP hydrolysis, performed by two co-operating ABC units. Orthovanadate (Vi), a non-covalent inhibitor of the ABC ATPases, was found to catalyse a photo-oxidative cleavage of various ATP-binding proteins. In the present study, we have identified three Vi-cleavage sites within MRP1, and found that the cleavage reactions were variably modulated by the presence of nucleotides and by transported substrates. We concluded that Vi cleavage of MRP1 at Site I detects conformational changes due to the binding of MgATP. In contrast, Site II could be identified as part of the substrate-modulated catalytic cycle, probably containing an MRP1·MgADP·Vi transition-state-like complex. Cleavage at Site III was modulated by both the binding and hydrolysis of MgATP, in a biphasic pattern, which was also affected by the presence of transported substrates. We detected two different allosteric effects and found that they control two consecutive steps of the MRP1 ATPase catalytic cycle. Nucleotide binding to the low-affinity site accelerated the formation of the pre-hydrolytic intermediate in the other catalytic centre. Interaction of the transporter with its transported substrates stimulated a later reaction of the hydrolytic cycle, the formation of the post-hydrolytic intermediate, which could be detected in both catalytic sites by the experimental strategy used.

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18

Moug, R., A. Alfaro-Martinez, L. Peng, T. Garcia, V. Deligiannakis, A. Shen y M. Tamargo. "Selective etching of InGaAs/InP substrates from II-VI multilayer heterostructures". physica status solidi (c) 9, n.º 8-9 (6 de julio de 2012): 1728–31. http://dx.doi.org/10.1002/pssc.201100716.

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Garcia, Thor Axtmann, Vasilios Deligiannakis, Candice Forrester, Ido Levy y Maria C. Tamargo. "Bi2 Se3 van der Waals Virtual Substrates for II-VI Heterostructures". physica status solidi (b) 254, n.º 11 (28 de agosto de 2017): 1700275. http://dx.doi.org/10.1002/pssb.201700275.

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Witt, Katarzyna, Waldemar Studziński y Daria Bożejewicz. "Possibility of New Active Substrates (ASs) to Be Used to Prevent the Migration of Heavy Metals to the Soil and Water Environments". Molecules 28, n.º 1 (22 de diciembre de 2022): 94. http://dx.doi.org/10.3390/molecules28010094.

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This paper aims to propose an alternative to the known permeable reactive barriers (PRBs). PRB is one of the methods, which is a reactive barrier placed below the ground, to clean up contaminated groundwater. New polymer active substrates (ASs) were used to prevent soil contamination by toxic heavy metals. The active substrates consisted of a mixture of poly(vinyl chloride), Aliquat 336, and bis(2-ethylhexyl)adipate, which was applied to the skeleton material (fiberglass or textile). Aliquat 336 was used as a binding agent for metal ions (Cr(VI), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II)). In contrast with the PRBs, the ASs (from AS-1 to AS-5) were obtained in a simple way using the pouring method. The obtained ASs could be recycled and reused. The active substrates were used for the binding of various metal ions from aqueous solutions and the examined soil. It was found that the active substrate AS-1 decreased the concentrations of nickel, cadmium, and lead by more than 50% and that of chromium by more than 90% in the aqueous solution. High sorption efficiency for chromium and zinc metals (81% and 66%) with the use of AS-2 was also found, owing to which the migration of metals from soil to water can be limited. In the soil environment, active substrate AS-5 with the addition of a plasticizer showed the greatest effectiveness. This solution resulted in a reduction in each tested metal ion of at least 50%, and reductions in cadmium, lead, and copper of over 70%.

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Staudenmann, J. L., R. D. Horning y R. D. Knox. "Buerger precession camera and overall characterization of thin films and flat-plate crystals". Journal of Applied Crystallography 20, n.º 3 (1 de junio de 1987): 210–21. http://dx.doi.org/10.1107/s0021889887086813.

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A fast simple and non-destructive method is described to provide qualitative structural information for flat-plate crystals and epitaxically grown films. The technique, based upon the Buerger precession camera, produces an easy-to-interpret photograph of the reciprocal space of all the components at once: substrate, film or buffer layer, and/or superlattice. A wide variety of technologically important examples are used to illustrate the technique: a mixture of CdTe phases on (001) Si, an aluminium layer on a (001) Si substrate, (001) Ge epitaxic layers on (001) Si substrates, three combinations of possible orientations of CdTe epitaxic layers on various substrate types, CdTe/ZnTe and other II–VI superlattices on GaAs substrates. In addition, the precession pictures readily reveal the common [111] face-centered cubic twin fault, or stacking disorder, seen in bulk growth methods. This finding may have severe consequences for the electronic mobility and the feasibility of devices fabricated from these composite systems.

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22

Che, Song-Bek, Ichirou Nomura, Akihiko Kikuchi y Katsumi Kishino. "Yellow-green ZnCdSe/BeZnTe II-VI laser diodes grown on InP substrates". Applied Physics Letters 81, n.º 6 (5 de agosto de 2002): 972–74. http://dx.doi.org/10.1063/1.1492311.

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23

Wissmann, H., T. Tran Anh, S. Rogaschewski y M. von Ortenberg. "Self-organized MBE growth of II–VI epilayers on patterned GaSb substrates". Journal of Crystal Growth 201-202 (mayo de 1999): 619–22. http://dx.doi.org/10.1016/s0022-0248(98)01423-7.

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24

Wang, S., D. Ding, X. Liu, X. B. Zhang, D. J. Smith, J. K. Furdyna y Y. H. Zhang. "MBE growth of II–VI materials on GaSb substrates for photovoltaic applications". Journal of Crystal Growth 311, n.º 7 (marzo de 2009): 2116–19. http://dx.doi.org/10.1016/j.jcrysgro.2008.09.189.

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25

Kumar, Arun Babu, Sophia Masi, Farideh Ghomashchi, Naveen Kumar Chennamaneni, Makoto Ito, C. Ronald Scott, Frantisek Turecek, Michael H. Gelb y Zdenek Spacil. "Tandem Mass Spectrometry Has a Larger Analytical Range than Fluorescence Assays of Lysosomal Enzymes: Application to Newborn Screening and Diagnosis of Mucopolysaccharidoses Types II, IVA, and VI". Clinical Chemistry 61, n.º 11 (1 de noviembre de 2015): 1363–71. http://dx.doi.org/10.1373/clinchem.2015.242560.

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Abstract BACKGROUND There is interest in newborn screening and diagnosis of lysosomal storage diseases because of the development of treatment options that improve clinical outcome. Assays of lysosomal enzymes with high analytical range (ratio of assay response from the enzymatic reaction divided by the assay response due to nonenzymatic processes) are desirable because they are predicted to lead to a lower rate of false positives in population screening and to more accurate diagnoses. METHODS We designed new tandem mass spectrometry (MS/MS) assays that give the largest analytical ranges reported to date for the use of dried blood spots (DBS) for detection of mucopolysaccharidoses type II (MPS-II), MPS-IVA, and MPS-VI. For comparison, we carried out fluorometric assays of 6 lysosomal enzymes using 4-methylumbelliferyl (4MU)-substrate conjugates. RESULTS The MS/MS assays for MPS-II, -IVA, and -VI displayed analytical ranges that are 1–2 orders of magnitude higher than those for the corresponding fluorometric assays. The relatively small analytical ranges of the 4MU assays are due to the intrinsic fluorescence of the 4MU substrates, which cause high background in the assay response. CONCLUSIONS These highly reproducible MS/MS assays for MPS-II, -IVA, and -VI can support multiplex newborn screening of these lysosomal storage diseases. MS/MS assays of lysosomal enzymes outperform 4MU fluorometric assays in terms of analytical range. Ongoing pilot studies will allow us to gauge the impact of the increased analytical range on newborn screening performance.

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Garcia, J. A., A. Remón, V. Munñz y R. Triboulet. "Annealing-induced Changes in the Electronic and Structural Properties of ZnTe Substrates". Journal of Materials Research 15, n.º 7 (julio de 2000): 1612–16. http://dx.doi.org/10.1557/jmr.2000.0231.

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The aim of this study is to demonstrate that the electronic and structural properties of II–VI substrates, here ZnTe, can be dramatically affected by thermal heating at temperatures in the range of those typically used in the epitaxial metalorganic chemical vapor deposition processes. Photoluminescence response shows that annealing at these temperatures produces a reduction of the sample crystalline quality, decreasing the free exciton emission relative to the deep level related one. Some factors, like the change in the charge and stress state of dislocations, Cu diffusion, and oxygen incorporation, could be responsible for changes in the substrate properties, which can produce stresses and contamination in the deposited sample.

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MONAICO, Eduard V. "MICRO- AND NANO-ENGINEERING OF SEMICONDUCTOR COMPOUNDS AND METAL STRUCTURES BASED ON ELECTROCHEMICAL TECHNOLOGIES". Annals of the Academy of Romanian Scientists Series on Physics and Chemistry 9, n.º 1 (30 de agosto de 2024): 85–107. http://dx.doi.org/10.56082/annalsarsciphyschem.2024.1.85.

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This paper aims to address the challenges of micro- and nano-engineering semiconductor compounds and fabricating metal-semiconductor nanocomposite materials by developing theoretical concepts for the application of electrochemical nanostructuring technologies to semiconductor substrates. It includes identifying the technological conditions for controlled electrochemical etching to create nanostructured semiconductor templates with wide bandgaps, such as III-V semiconductors (InP, GaAs, GaN) and II-VI compounds (CdSe, ZnSe, ZnxCd1-xS). The study also demonstrates the conditions for electrochemical metal deposition in porous semiconductor templates and investigates the laws and mechanisms of metal deposition depending on the composition of the semiconductor substrates and current pulse parameters. Additionally, the paper addresses the conditions for electrochemical etching of semiconductor substrates to produce nanowire networks with directed alignment to the substrate surface, instead of merely producing porous layers. A comprehensive investigation of the properties of the developed nanostructures and materials is proposed to demonstrate their applicability in nanoelectronic, optoelectronic, and photonic devices.

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28

Anderson, Thomas, Donovan L. Barrett, J. Chen, Ejiro Emorhokpor, A. Gupta, R. H. Hopkins, Andrew E. Souzis et al. "Growth of Large Diameter SiC Crystals by Advanced Physical Vapor Transport". Materials Science Forum 483-485 (mayo de 2005): 9–12. http://dx.doi.org/10.4028/www.scientific.net/msf.483-485.9.

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Semi-insulating 6H SiC substrates, 2”, 3” and 100mm in diameter, and n+ 4H SiC substrates, 2” and 3” in diameter, are grown at II-VI using the Advanced Physical Vapor Transport (APVT) technique [1]. The process utilizes high-purity SiC source and employs special measures aimed at the reduction of background contamination. Semi-insulating properties are achieved by precise vanadium compensation, which yields substrates with stable and uniform electrical resistivity reaching ~ 1011 Ω-cm and higher. Conductive n+ 4H SiC crystals with the spatially uniform resistivity of 0.02 W-cm are grown using nitrogen doping. Crystal quality of the substrates, their electrical properties and low temperature photoluminescence are discussed.

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KOUMANOV, Kamen, Claude WOLF y Gilbert BÉREZIAT. "Modulation of human type II secretory phospholipase A2 by sphingomyelin and annexin VI". Biochemical Journal 326, n.º 1 (15 de agosto de 1997): 227–33. http://dx.doi.org/10.1042/bj3260227.

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Conjectural results have been reported on the capacity of inflammatory secreted phospholipase A2 (sPLA2) to hydrolyse mammalian membrane phospholipids. Development of an assay based on the release of non-esterified fatty acids by the enzyme acting on the organized phospholipid mixture constituting the membrane matrix has led to the identification of two prominent effectors, sphingomyelin (SPH) and annexin. Recombinant human type II sPLA2 hydrolyses red-cell membrane phospholipids with a marked preference for the inner leaflet. This preference is apparently related to the high content of SPH in the outer leaflet, which inhibits sPLA2. This inhibition by SPH is specific for sPLA2. Cholesterol counteracts the inhibition of sPLA2 by SPH, suggesting that the SPH-to-cholesterol ratio accounts in vivo for the variable susceptibility of cell membranes to sPLA2. Different effects were observed of the presence of the non-hydrolysable D-α-dipalmitoyl phosphatidylcholine (D-DPPC), which renders the membranes rigid but does not inhibit sPLA2. Annexin VI was shown, along with other annexins, to inhibit sPLA2 activity by sequestering the phospholipid substrate. The present study has provided the first evidence that annexin VI, in concentrations that inhibit hydrolysis of purified phospholipid substrates, stimulated the hydrolysis of membrane phospholipids by sPLA2. The activation requires the presence of membrane proteins. The effect is specific for type II sPLA2 and is not reproducible with type I PLA2. The activation by annexin VI of sPLA2 acting on red cell membranes results in the preferential release of polyunsaturated fatty acids. It suggests that type II sPLA2, in conjunction with annexin VI, might be involved in the final step of endocytosis and/or exocytosis providing the free polyunsaturated fatty acids acting synergistically to cause membrane fusion.

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Stoica, V. A., L. Endicott, H. H. Shen, W. Liu, K. Sun, C. Uher y R. Clarke. "High-quality II-VI films grown on amorphous substrates using tunable tetradymite templates". Applied Physics Letters 105, n.º 22 (1 de diciembre de 2014): 221606. http://dx.doi.org/10.1063/1.4903268.

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31

Ashenford, D., D. Johnston, B. Lunn y C. G. Scott. "Characteristics of II-VI semiconductor thin films grown by MBE on InSb substrates". Journal of Physics: Condensed Matter 1, SB (1 de octubre de 1989): SB51—SB54. http://dx.doi.org/10.1088/0953-8984/1/sb/010.

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32

Sidorov, Yu G., M. V. Yakushev, D. N. Pridachin, V. S. Varavin y L. D. Burdina. "The heteroepitaxy of II–VI compounds on the non-isovalent substrates (ZnTe/Si)". Thin Solid Films 367, n.º 1-2 (mayo de 2000): 203–9. http://dx.doi.org/10.1016/s0040-6090(00)00674-x.

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Hughes, W. C., C. Boney, M. A. L. Johnson, J. W. Cook y J. F. Schetzina. "Surface preparation of ZnSe substrates for MBE growth of II–VI light emitters". Journal of Crystal Growth 175-176 (mayo de 1997): 546–51. http://dx.doi.org/10.1016/s0022-0248(96)01022-6.

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34

Gessert, T. A., E. Colegrove, B. Stafford, R. Kodama, Wei Gao, H. R. Moutinho, D. Kuciauskas, R. C. Reedy, T. M. Barnes y S. Sivananthan. "II-VI Material Integration With Silicon for Detector and PV Applications". MRS Advances 1, n.º 50 (2016): 3391–402. http://dx.doi.org/10.1557/adv.2016.408.

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ABSTRACTHeteroepitaxial growth of high-quality II-VI-alloy materials on Si substrates is a well-established commercial growth process for infrared (IR) detector devices. However, it has only recently been recognized that these same processes may have important applications for production of high-efficiency photovoltaic devices. This submission reviews the process developments that have enabled effective heteroepitaxy of II-VI alloy materials on lattice-mismatched Si for IR detectors as a foundation to describe recent efforts to apply these insights to the fabrication of multijunction Si/CdZnTe devices with ultimate conversion efficiencies >40%. Reviewed photovoltaic studies include multijunction Si/CdZnTe devices with conversion efficiency of ∼17%, analysis of structural and optoelectrical quality of undoped CdTe epilayer films on Si, and the effect that a Te-rich growth environment has on the structural and optoelectronic quality of both undoped and As-doped heteroepitaxial CdTe.

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35

Sorokin, Sergey V., Pavel S. Avdienko, Irina V. Sedova, Demid A. Kirilenko, Valery Yu Davydov, Oleg S. Komkov, Dmitrii D. Firsov y Sergey V. Ivanov. "Molecular Beam Epitaxy of Layered Group III Metal Chalcogenides on GaAs(001) Substrates". Materials 13, n.º 16 (5 de agosto de 2020): 3447. http://dx.doi.org/10.3390/ma13163447.

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Development of molecular beam epitaxy (MBE) of two-dimensional (2D) layered materials is an inevitable step in realizing novel devices based on 2D materials and heterostructures. However, due to existence of numerous polytypes and occurrence of additional phases, the synthesis of 2D films remains a difficult task. This paper reports on MBE growth of GaSe, InSe, and GaTe layers and related heterostructures on GaAs(001) substrates by using a Se valve cracking cell and group III metal effusion cells. The sophisticated self-consistent analysis of X-ray diffraction, transmission electron microscopy, and Raman spectroscopy data was used to establish the correlation between growth conditions, formed polytypes and additional phases, surface morphology and crystalline structure of the III–VI 2D layers. The photoluminescence and Raman spectra of the grown films are discussed in detail to confirm or correct the structural findings. The requirement of a high growth temperature for the fabrication of optically active 2D layers was confirmed for all materials. However, this also facilitated the strong diffusion of group III metals in III–VI and III–VI/II–VI heterostructures. In particular, the strong In diffusion into the underlying ZnSe layers was observed in ZnSe/InSe/ZnSe quantum well structures, and the Ga diffusion into the top InSe layer grown at ~450 °C was confirmed by the Raman data in the InSe/GaSe heterostructures. The results on fabrication of the GaSe/GaTe quantum well structures are presented as well, although the choice of optimum growth temperatures to make them optically active is still a challenge.

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36

Jung, M. N., S. Y. Ha, H. S. Kim, H. J. Ko, H. Ko, W. H. Lee, D. C. Oh, Y. Murakami, T. Yao y J. H. Chang. "The Shape Control of ZnO Based Nanostructures". Journal of Nanoscience and Nanotechnology 6, n.º 11 (1 de noviembre de 2006): 3628–32. http://dx.doi.org/10.1166/jnn.2006.17996.

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Tetrapod-shape ZnO nanostructures are formed on Si substrates by vapor phase transportation method. The effects of two important growth parameters, growth temperature and VI/II ratio, are investigated. The growth temperature is varied in the range from 600 °C to 900 °C to control the vapor pressure of group II-element and the formation process of nanostructures. VI/II ratio was changed by adjusting the flux of carrier gas which affects indirectly the supplying rate of group VI-element. From the scanning electron microscopy (SEM), systematic variation of shape including cluster, rod, wire and tetrapod was observed. ZnO tetrapods, formed at 800 °C under the carrier gas flux of 0.5 cc/mm2 min, show considerably uniform shape with 100 nm thick and 1 ∼ 1.5 μm long legs. Also stoichiometric composition (O/Zn ∼ 1) was observed without any second phase structures. While, the decrease of growth temperature and the increase of carrier gas flux, results in the irregular shaped nanostructures with non-stoichiometric composition. The excellent luminescence properties, strong excitonic UV emission at 3.25 eV without deep level emission, indicate that the high crystalline quality tetrapod structures can be formed at the optimized growth conditions.

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37

Brown, P. D., Y. Y. Loginov, W. M. Stobbs y C. J. Humphreys. "Microtwin nucleation and propagation in heteroepitaxial II-VI compounds on (001)-oriented GaAs substrates". Philosophical Magazine A 72, n.º 1 (julio de 1995): 39–57. http://dx.doi.org/10.1080/01418619508239581.

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38

Kobayashi, Ryohei, Shingo Takamatsu, Koji Fukushima, Katsumi Kishino y Ichirou Nomura. "Investigation of yellow/green II-VI compound semiconductor laser diode structures on InP substrates". physica status solidi (c) 13, n.º 7-9 (16 de marzo de 2016): 669–72. http://dx.doi.org/10.1002/pssc.201510255.

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39

Gupta, Avinash K., Ping Wu, Varatharajan Rengarajan, Xue Ping Xu, Murugesu Yoganathan, Christ Martin, Ejiro Emorhokpor, Andy Souzis, Ilya Zwieback y Tom Anderson. "Status of Large Diameter SiC Single Crystals". Materials Science Forum 717-720 (mayo de 2012): 3–8. http://dx.doi.org/10.4028/www.scientific.net/msf.717-720.3.

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Large-diameter SiC single crystals are grown at II-VI by the sublimation technique. 100mm substrates of semi-insulating 6H SiC and n-type 4H SiC are produced as commercial products; in development, diameter expansion to 125mm has been achieved. Over the last two years, significant improvements have been made in crystal quality. The values of FWHM of x-ray rocking curves are typically 20-40 arc-seconds for 6H SI wafers and 12-30 arc-seconds for 4H n+ wafers. Micropipe density is less than 3 cm-2, and less than 0.1 cm-2 in best substrates. Electrical resistivity of SI substrates is, typically, of 1011 Ω•cm or above. For 4H n+ substrates, the typical dislocation density is about 9×103 cm-2 and the typical BPD density is less than 1×103 cm-2.

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40

Doğan, S., Y. Ayyildiz, M. Doğan, ü. Alan y M. E. Diken. "Characterisation of polyphenol oxidase from Melissa officinalis L. subsp. officinalis (lemon balm)". Czech Journal of Food Sciences 31, No. 2 (18 de abril de 2013): 156–65. http://dx.doi.org/10.17221/288/2011-cjfs.

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Polyphenol oxidase (PPO) from Melissa officinalis L. subsp. officinalis (lemon balm) was partially purified by ammonium sulphate precipitation and dialysis; and then it was characterised in detail in terms of pH and temperature optima, thermal stability, kinetic parameters, and inhibition properties. Based on experimental results, it was found out that (i) the optimum pH and temperature values of PPO were 6.5, 4.0, and 8.5 and 40, 50, and 60°C for catechol, 4-methylcatechol and pyrogallol substrates, respectively; (ii) the best substrate was pyrogallol due to the highest V<sub>max</sub>/K<sub>m</sub> value, followed by catechol and 4-methylcatechol; (iii) enzyme activity decreased due to heat denaturation of the enzyme with increasing temperature and inactivation time for all substrates; (vi) gallic acid and l-glutamic acid did not inhibit PPO; and (v) the most effective inhibitor was glutathione. Furthermore, the phenolic and protein contents of lemon balm extract were also determined according to the Folin-Ciocalteu and Bradford methods, respectively.  

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41

Zaumseil, Peter, Grzegorz Kozlowski, Yuji Yamamoto, Markus Andreas Schubert y Thomas Schroeder. "X-ray characterization of Ge dots epitaxially grown on nanostructured Si islands on silicon-on-insulator substrates". Journal of Applied Crystallography 46, n.º 4 (7 de junio de 2013): 868–73. http://dx.doi.org/10.1107/s0021889813003518.

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On the way to integrate lattice mismatched semiconductors on Si(001), the Ge/Si heterosystem was used as a case study for the concept of compliant substrate effects that offer the vision to be able to integrate defect-free alternative semiconductor structures on Si. Ge nanoclusters were selectively grown by chemical vapour deposition on Si nano-islands on silicon-on-insulator (SOI) substrates. The strain states of Ge clusters and Si islands were measured by grazing-incidence diffraction using a laboratory-based X-ray diffraction technique. A tensile strain of up to 0.5% was detected in the Si islands after direct Ge deposition. Using a thin (∼10 nm) SiGe buffer layer between Si and Ge the tensile strain increases to 1.8%. Transmission electron microscopy studies confirm the absence of a regular grid of misfit dislocations in such structures. This clear experimental evidence for the compliance of Si nano-islands on SOI substrates opens a new integration concept that is not only limited to Ge but also extendable to semiconductors like III–V and II–VI materials.

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42

Ahmad, Farhan, Nadir Qurban, Zain Fatima, Toqeer Ahmad, Iqra Zahid, Ahmad Ali, Sehrish Rana Rajpoot, Muhammad Wasim Tasleem y Esha Maqbool. "Electrical Characterization of II-VI Thin Films for Solar Cells Application". ASEAN Journal of Science and Engineering 2, n.º 3 (10 de febrero de 2022): 199–208. http://dx.doi.org/10.17509/ajse.v2i3.39425.

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Cds and CdTe both are effective absorber semiconductors for thin-film solar cells. It is a naturally n-type material, which has a direct bandgap value of 2.42 eV at room temperature It has great importance in light detectors in this work, CdS thin films (TF) were synthesized on glass substrates by RF Magnetron sputtering technique in an inert gas atmosphere. The electrical properties of CdS were characterized by the Van Der Pauw method. The films showed p-type conductivity, while the films deposited at different annealed times exhibited n-type conductivity. The resistivity of the CdTe films decrease as the conductivity increased. As the source rate was increased, the hole concentration in the as-grown p-type CdTe films increased. It was also reported annealing process affects the electrical properties. Al doping CdS the value of resistivity becomes minimum as the resistivity becomes maximum although mobility has maximum value after an increase in Al doping the mobility value. As a result, the CdS/CdTe thin-film showed enhanced electrical properties for solar cell applications.

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43

Butashin, A. V., V. M. Kanevskii, A. E. Muslimov, E. V. Rakova, V. I. Mikhailov, V. A. Babaev, A. M. Ismailov y M. Kh Rabadanov. "Specific features of the growth of A II B VI films on (0001)Al2O3 substrates". Crystallography Reports 59, n.º 3 (mayo de 2014): 418–21. http://dx.doi.org/10.1134/s1063774514030067.

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44

Ouyang, L., X.-B. Zhang, S. Wang, X. Lu, Y.-H. Zhang, X. Liu, J. Furdyna y DJ Smith. "Lattice-Matched II-VI/III-V Materials and Virtual Substrates for Multijunction Solar-Cell Applications". Microscopy and Microanalysis 16, S2 (julio de 2010): 1350–51. http://dx.doi.org/10.1017/s1431927610062811.

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45

Di Cioccio, L., A. Million, J. Piaguet, G. Rolland, G. Lentz, N. Magnea y H. Mariette. "Twin free growth of II–VI compounds on (111) CdZnTe substrates by molecular beam epitaxy". Journal of Crystal Growth 95, n.º 1-4 (febrero de 1989): 552–56. http://dx.doi.org/10.1016/0022-0248(89)90464-8.

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46

Yu, Z. "High-brightness II–VI light-emitting diodes grown by molecular-beam epitaxy on ZnSe substrates". Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures 13, n.º 2 (marzo de 1995): 711. http://dx.doi.org/10.1116/1.588143.

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47

Patriarche, G., J. P. Rivière, J. Castaing, A. Tromson Carli, R. Triboulet y Y. Marfaing. "Extended defects in II-VI semiconductor heteroepitaxial layers grown on GaAs substrates of various orientations". Physica Status Solidi (a) 138, n.º 2 (16 de agosto de 1993): 437–43. http://dx.doi.org/10.1002/pssa.2211380211.

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48

Kozlovsky, V. I., V. P. Martovitsky, Ya K. Skasyrsky, Yu G. Sadofyev y A. G. Turyansky. "MBE Growth of II-VI Epilayers and QW Structures on Hexagonal ZnCdS and CdSSe Substrates". physica status solidi (b) 229, n.º 1 (enero de 2002): 63–67. http://dx.doi.org/10.1002/1521-3951(200201)229:1<63::aid-pssb63>3.0.co;2-8.

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49

Yoganathan, Murugesu, Ejiro Emorhokpor, Thomas Kerr, A. Gupta, C. D. Tanner y Ilya Zwieback. "Characterization of SiC Substrates Using X-Ray Rocking Curve Mapping". Materials Science Forum 527-529 (octubre de 2006): 729–32. http://dx.doi.org/10.4028/www.scientific.net/msf.527-529.729.

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SiC substrates produced at II-VI, Inc. have been characterized using x-ray rocking curve mapping (topography). The rocking curves have been measured in the -scan mode for the (0006) Bragg reflection of 6H and the (0004) reflection of 4H SiC substrates. The maps contain information extracted from the rocking curves, such as the peak angle () and the rocking curve broadening (FWHM). In the case when lattice distortion is present due to the elastic or plastic deformation, the peak angle () changes gradually upon scanning, with the d/dx gradient proportional to the lattice curvature in the plane of diffraction. Multi-peak reflections and/or sharp change in the value of indicate the presence of misoriented grains. X-ray rocking curve mapping of SiC substrates yields excellent measures of crystalline quality that contain important information on the lattice strain and sub-grain misorientation.

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50

Gupta, A., E. Semenas, Ejiro Emorhokpor, J. Chen, Ilya Zwieback, Andrew E. Souzis y Thomas Anderson. "Growth and Characterization of Large Diameter 6H and 4H SiC Single Crystals". Materials Science Forum 527-529 (octubre de 2006): 43–46. http://dx.doi.org/10.4028/www.scientific.net/msf.527-529.43.

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Over the past year, II-VI has transitioned from 2” to 3” commercial SiC substrates. Large-diameter semi-insulating 6H-SiC and n-type 4H-SiC single crystals are grown using the Advanced PVT growth process. Expansion of boule diameter from 2 to 3 and up to 4.25 inches has been carried out using a specially designed growth technique. Stable semi-insulating properties in 6H-SiC are achieved by precise vanadium compensation. The technique of compensation is optimized to produce a controlled and spatially uniform distribution of vanadium and high and spatially uniform electrical resistivity reaching 10 10 – 1011 ·cm. N-type 3-inch 4H-SiC crystals are grown using doping with nitrogen, and 3-inch 4H-SiC substrates show uniform resistivity of about 0.018 ·cm. The best quality semiinsulating (SI) 3” 6H-SiC substrates demonstrate micropipe density of 3 cm-2, and n-type 3” 4H-SiC substrates - about 1 cm-2. X-ray rocking curve topography of the produced 3” SiC substrates is used for evaluation of their crystal quality.

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