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Your search keyword '"Nikitina, I. P."' showing total 227 results
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227 results on '"Nikitina, I. P."'

52. Liquid Phase Epitaxy of SiC-AlN Solid Solutions

Author

Dmitriev, V. A., Elfimov, L. B., Lin’kov, I. Yu., Morozenko, Ya. V., Nikitina, I. P., Chelnokov, V. E., Cherenkov, A. E., Chernov, M. A., Lotsch, H. K. V., editor, Yang, Cary Y., editor, Rahman, M. Mahmudur, editor, and Harris, Gary L., editor

Published
1992
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62. Templates for homoepitaxial growth of 3C-SiC obtained by direct bonding of silicon carbide wafers of differing polytype

Author

null Lebedev A. A., null Davydov V. Yu., null Lebedev S. P., null Nikitina I. P., null Smirnov A. N., null Amelchuk D. G., and null Mynbaeva M. G.

Abstract

An approach of direct bonding of SiC wafers of differing polytypes has been implemented in order to create a template for cubic 3C-SiC homoepitaxy. Heteroepitaxial 3C-SiC layers grown by chemical vapor deposition were transferred onto a hexagonal 6H-SiC wafer. The results of structural characterization showed that the quality of 3C-SiC sublimation epitaxy on the templates is comparable to the level of epitaxy of cubic silicon carbide by chemical vapor deposition method. It was confirmed that the 3C-SiC layer transferred onto the 6H-SiC substrate plays the role of a crystalline "seed" that determines cubic polytype of the overgrown SiC layer. Keywords: Silicon carbide, polytypes, direct bonding, templates, sublimation epitaxy.

Published
2022

96. Formation and role of graphite and nickel silicide in nickel based ohmic contacts to n-type silicon carbide.

Author

Nikitina, I. P., Vassilevski, K. V., Wright, N. G., Horsfall, A. B., O'Neill, A. G., and Johnson, C. M.

Subjects
*SILICON carbide, *GRAPHITE, *NICKEL, *ELECTRIC fields, *THERMAL conductivity, *SILICON compounds, *ELECTRICAL engineering, *PHYSICS
Abstract

Nickel-based contacts, deposited on 4H-SiC C-face substrates, were annealed at temperatures ranging from 800 to 1040 °C and the phase composition of the contact layers analyzed by x-ray diffraction techniques. Ni2Si was identified as the dominant phase for annealing temperatures exceeding 925 °C, with further increases in concentration with increasing temperature. At the highest annealing temperature of 1040 °C, a 40 nm thick nanocrystalline graphite film at the Ni2Si–SiC interface was discovered and its presence confirmed by Raman spectroscopy. The roles of the Ni2Si and graphite films in the formation of ohmic contacts were determined by their subsequent exclusion from the contact composition. Following deposition and annealing, the Ni2Si and graphite layers were etched away selectively and replaced with new metal films deposited at room temperature and without any annealing. Measurement of the current-voltage characteristics revealed that the ohmic nature of the contacts was preserved after removal of the Ni2Si and the graphite layers. It is concluded that the main reason for the conversion of Schottky to ohmic contacts during high-temperature annealing is a change of the electrical properties of the underlying SiC rather than being attributable to the presence of nickel silicides or graphite. It is proposed that a solid-state reaction between nickel and silicon carbide, similar to catalytic graphitization of carbon, may take place during Ni–SiC contact annealing at the temperature of 1040 °C. This process may result in the creation of sufficient carbon vacancies in the near-interface region of the SiC to allow increased electron transport through the Schottky barrier. [ABSTRACT FROM AUTHOR]

Published
2005
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97. Oxygen-Mediated Superexchange Interactions and Their Impact on the Structural Stability, Magnetic Order, and Magnetocrystalline Anisotropy of One-Dimensional Co-Oxide Chains on Rh(553) Step-Surfaces

Author

Korobova, J. G., Nikitina, I. A., Bazhanov, D. I., and Ruiz-Díaz, P.

Abstract

First-principles calculations in the framework of the generalized gradient approximation together with Uon-site Coulomb corrections in the GGA + U approach to density functional theory (DFT) are performed to investigate the structural stability, magnetic order, and magnetocrystalline anisotropy of one-dimensional (1D) cobalt-oxide chains on Rh(553) step-surfaces. We found that the chains’ magnetic and structural stability strongly depends on the oxygen concentration, η. It is determined that there exist competing direct ferromagnetic and indirect antiferromagnetic exchange interactions in the doped-oxygen 1D linear chains, and in general, the oxygen doping stabilizes the antiferromagnetism. For pure Co linear chains and low oxygen concentrations, in which η ≤ 0.1 monolayers (ML), the ferromagnetic solution is the ground-state magnetic configuration. For η > 0.2 ML, the antiferromagnetic arrangement stabilizes through superexchange interactions. The strong influence regarding the oxygen-doping on the Co linear chains’ structural properties is evidenced when a small dimerization between the Co atoms at low O concentrations emerges. In contrast, dimerization in the Co chains is suppressed when the system is “oxygen-free” or η > 0.2 ML. The increase of oxygen concentration strengthens the pdhybridization between Co d-states and O p-states, leading to an electronic redistribution of the majority and minority bands of the Co d-states. Such a redistribution yields to the formation of more localized bands. A significant reduction of the local magnetic moment in the Co atoms is followed. The robustness of the DFT + U results is also discussed to some extent. Throughout a perturbative analysis, we also investigate the oxygen dependence on the magnetocrystalline anisotropy energy (MAE) for the Co-oxide chains, which ranges from 0.4 to 1.2 meV. Interestingly, magnetization directions canted to the wires’ direction or perpendicular to the Rh terrace are determined. Their origins are discussed in terms of the local contributions to the MAE.

Published
2020
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99. OPTICAL PROPERTIES OF BULK GALLIUM OXIDE GROWN FROM THE MELT.

Author

Mynbaeva, M. G., Shirshnev, P. S., Kremleva, A. V., Smirnov, A. N., Ivanova, E. V., Zamoryanskaya, M. V., Nikitina, I. P., Lavrent'ev, A. A., Mynbaev, K. D., Odnoblyudov, M. A., Bauman, D. A., Lipsanen, H., Nikolaev, V. I., Bougrov, V. E., and Romanov, A. E.

Subjects
OPTICAL properties, GALLIUM, OXIDES, RAMAN spectroscopy, PHONONS
Abstract

Results of the studies of the properties of single-crystalline bulk β-Ga2O3 grown from the melt are presented. High chemical purity and phase uniformity of the grown material are demonstrated. Raman spectroscopy studies confirmed low energies of optical phonons in β-Ga2O3, which makes it a promising material for laser optics applications. [ABSTRACT FROM AUTHOR]

Published
2018
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100. Raman and photoluminescence studies of biaxial strain in GaN epitaxial layers grown on 6H-SiC.

Author

Davidov, V. Yu., Averkiev, N.S., Goncharuk, I. N., Nelson, D. K., Nikitina, I. P., Polkovnikov, A. S., Smirnov, A. N., Jacobson, M. A., and Semchinova, O. K.

Subjects
PHONONS, RAMAN spectroscopy, STRAINS & stresses (Mechanics)
Abstract

Discusses the effect of biaxial strain on optical phonons in high-quality GaN epitaxial layers grown on 6H-SiC substrates by metal organic chemical vapor deposition. Comparative analysis of the strain measured by x-ray diffraction and Raman spectroscopy; Study of the effect of strain on the optical phonon modes of GaN and related deformation potential constants.

Published
1997

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