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Your search keyword '"Gogova, Daniela"' showing total 125 results
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125 results on '"Gogova, Daniela"'

1. Response to 'Comment on 'A novel two-dimensional boron-carbon-nitride (BCN) monolayer: A first-principles insight [J. Appl. Phys. 2021, 130, 114301]''

Author

Bafekry, Asadollah, Naseri, Mosayeb, Fadlallah, Mohamed M., Sarsari, Ismaeil Abdolhosseini, faraji, Mehrdad, khatibani, Abbas bagheri, Ghergherehchi, Mitra, and Gogova, Daniela

Subjects
Physics - Computational Physics
Abstract

Recently, reported a comments on the our paper [JAP21-AR-03574R].. For clarification, we applied the fingerprint theory to examine the similarity between the distinct structures. The fingerprint function is a crystal structure descriptor, an 1D-function related to the pair correlation function and diffraction patterns. It does not depend on absolute atomic coordinates, but only on interatomic distances. Small deviations in atomic positions will influence the fingerprints only slightly [1-3]. Fingerprint theory allows quantification of the degree of order and complexity of a crystal structure.

Published
2022

3. Ion implantation in \b{eta}-Ga2O3: physics and technology

Author

Nikolskaya, Alena, Okulich, Evgenia, Korolev, Dmitry, Stepanov, Anton, Nikolichev, Dmitry, Mikhaylov, Alexey, Tetelbaum, David, Almaev, Aleksei, Bolzan, Charles Airton, Buaczik, Antônio Jr, Giulian, Raquel, Grande, Pedro Luis, Kumar, Ashok, Kumar, Mahesh, and Gogova, Daniela

Subjects
Condensed Matter - Materials Science
Abstract

Gallium oxide and in particular its thermodynamically stable \b{eta}-Ga2O3 phase is within the most exciting materials in research and technology nowadays due to its unique properties, such as an ultra-wide band gap and a very high breakdown electric field, finding a number of applications in electronics and optoelectronics. Ion implantation is a traditional technological method used in these fields, and its well-known advantages can contribute greatly to the rapid development of physics and technology of Ga2O3-based materials and devices. Here, the current status of ion beam implantation in \b{eta}-Ga2O3 is reviewed. The main attention is paid to the results of experimental study of damage under ion irradiation and the properties of Ga2O3 layers doped by ion implantation. The results of ab initio theoretical calculations of the impurities and defects parameters are briefly presented, and the physical principles of a number of analytical methods used to study implanted gallium oxide layers are highlighted. The use of ion implantation in the development of such Ga2O3-based devices as metal oxide field effect transistors, Schottky barrier diodes, and solar-blind UV detectors, is described together with systematical analysis of the achieved values of their characteristics. Finally, the most important challenges to be overcome in this field of science and technology are discussed.

Published
2021
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6. Molecular Effect in Damage Formation in β-Ga2O3

Author

Karabeshkin, Konstantin V., Struchkov, Andrei I., Titov, Andrei I., Azarov, Alexander, Gogova, Daniela S., Karaseov, Platon A., Velichko, Elena, editor, Kapralova, Viktoria, editor, Karaseov, Platon, editor, Zavjalov, Sergey, editor, Angueira, Pablo, editor, and Andreev, Sergey, editor

Published
2022
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11. Surface roughness evolution in a solid-on-solid model of epitaxial growth

Author

Petrov, Petar P. and Gogova, Daniela

Subjects
Condensed Matter - Materials Science
Abstract

The paper presents results from kinetic Monte Carlo simulations of kinetic surface roughening using an important and experimentally relevant model of epitaxial growth -- the solid-on-solid model with Arrhenius dynamics. A restriction on diffusing adatoms is included allowing hopping down only at steps of height one monolayer in order to avoid possibly unrealistic events of jumping from arbitrarily high steps. Simulation results and precise analytic expressions representing the time evolution of surface roughness do not depend on the substrate size and clearly put forward the conclusion that for any basic set of parameters the model approaches in asymptotic limit the usual random deposition process with growth exponent $\beta=1/2$. At high temperatures, it is preceded by a long transient regime characterized by a smooth surface covered with porous pillars and described by a power law with $\beta=3/4$., Comment: 14 pages, 4 figures and a table

Published
2014
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21. Epitaxial growth of β-Ga2O3 by hot-wall MOCVD

Author

Gogova, Daniela, primary, Ghezellou, Misagh, additional, Tran, Dat Q., additional, Richter, Steffen, additional, Papamichail, Alexis, additional, Hassan, Jawad ul, additional, Persson, Axel R., additional, Persson, Per O. Å., additional, Kordina, Olof, additional, Monemar, Bo, additional, Hilfiker, Matthew, additional, Schubert, Mathias, additional, Paskov, Plamen P., additional, and Darakchieva, Vanya, additional

Published
2022
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25. Point defects in a two-dimensional ZnSnN₂ nanosheet : a first-principles study on the electronic and magnetic properties

Author

Bafekry, Asadollah, Faraji, Mehrdad, Fadlallah, Mohamed M., Mortazavi, Bohayra, Ziabari, A. Abdolahzadeh, Khatibani, A. Bagheri, Nguyen, Chuong, V, Ghergherehchi, Mitra, and Gogova, Daniela

Subjects
Chemistry, Physics, Engineering sciences. Technology
Abstract

The reduction of dimensionality is a very effective way to achieve appealing properties in two-dimensional materials (2DMs). First-principles calculations can greatly facilitate the prediction of 2DM properties and find possible approaches to enhance their performance. We employed first-principles calculations to gain insight into the impact of different types of point defects (vacancies and substitutional dopants) on the electronic and magnetic properties of a ZnSnN2 (ZSN) monolayer. We show that Zn, Sn, and N + Zn vacancy-defected structures are p-type conducting, while the defected ZSN with a N vacancy is n-type conducting. For substitutional dopants, we found that all doped structures are thermally and energetically stable. The most stable structure is found to be B-doping at the Zn site. The highest work function value (5.0 eV) has been obtained for Be substitution at the Sn site. Li-doping (at the Zn site) and Be-doping (at the Sn site) are p-type conducting, while B-doping (at the Zn site) is n-type conducting. We found that the considered ZSN monolayer-based structures with point defects are magnetic, except those with the N vacancy defects and Be-doped structures. The ab initio molecular dynamics simulations confirm that all substitutionally doped and defected structures are thermally stable. Thus, our results highlight the possibility of tuning the magnetism in ZnSnN2 monolayers through defect engineering.

Published
2021

27. Ion implantation in β-Ga2O3: Physics and technology

Author

Nikolskaya, Alena, primary, Okulich, Evgenia, additional, Korolev, Dmitry, additional, Stepanov, Anton, additional, Nikolichev, Dmitry, additional, Mikhaylov, Alexey, additional, Tetelbaum, David, additional, Almaev, Aleksei, additional, Bolzan, Charles Airton, additional, Buaczik, Antônio, additional, Giulian, Raquel, additional, Grande, Pedro Luis, additional, Kumar, Ashok, additional, Kumar, Mahesh, additional, and Gogova, Daniela, additional

Published
2021
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28. Epitaxial growth of β-Ga2O3 by hot-wall MOCVD.

Author

Gogova, Daniela, Ghezellou, Misagh, Tran, Dat Q., Richter, Steffen, Papamichail, Alexis, Hassan, Jawad ul, Persson, Axel R., Persson, Per O. Å., Kordina, Olof, Monemar, Bo, Hilfiker, Matthew, Schubert, Mathias, Paskov, Plamen P., and Darakchieva, Vanya

Subjects
*EPITAXY, *WIDE gap semiconductors, *SCANNING transmission electron microscopy, *EPITAXIAL layers, *METAL organic chemical vapor deposition, *SAPPHIRES
Abstract

The hot-wall metalorganic chemical vapor deposition (MOCVD) concept, previously shown to enable superior material quality and high performance devices based on wide bandgap semiconductors, such as Ga(Al)N and SiC, has been applied to the epitaxial growth of β-Ga2O3. Epitaxial β-Ga2O3 layers at high growth rates (above 1 μm/h), at low reagent flows, and at reduced growth temperatures (740 °C) are demonstrated. A high crystalline quality epitaxial material on a c-plane sapphire substrate is attained as corroborated by a combination of x-ray diffraction, high-resolution scanning transmission electron microscopy, and spectroscopic ellipsometry measurements. The hot-wall MOCVD process is transferred to homoepitaxy, and single-crystalline homoepitaxial β-Ga2O3 layers are demonstrated with a 2 ̄ 01 rocking curve width of 118 arc sec, which is comparable to those of the edge-defined film-fed grown ( 2 ̄ 01) β-Ga2O3 substrates, indicative of similar dislocation densities for epilayers and substrates. Hence, hot-wall MOCVD is proposed as a prospective growth method to be further explored for the fabrication of β-Ga2O3. [ABSTRACT FROM AUTHOR]

Published
2022
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29. Semiconducting Chalcogenide Alloys Based on the (Ge, Sn, Pb) (S, Se, Te) Formula with Outstanding Properties: A First-Principles Calculation Study

Author

Bafekry, Asadollah, primary, Shahrokhi, Masoud, additional, Shafique, Aamir, additional, Jappor, Hamad R., additional, Fadlallah, Mohamed M., additional, Stampfl, Catherine, additional, Ghergherehchi, Mitra, additional, Mushtaq, Muhammad, additional, Feghhi, Seyed Amir Hossein, additional, and Gogova, Daniela, additional

Published
2021
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35. ZnSnN2 in Real Space and k‐Space: Lattice Constants, Dislocation Density, and Optical Band Gap.

Author

Olsen, Vegard Skiftestad, Øversjøen, Vetle, Gogova, Daniela, Pécz, Béla, Galeckas, Augustinas, Borgersen, Jon, Karlsen, Kjetil, Vines, Lasse, and Kuznetsov, Andrej

Subjects
BAND gaps, LATTICE constants, DISLOCATION density, MAGNETRON sputtering, NITRIDES, OPTICAL lattices
Abstract

Semiconducting II‐IV nitrides exhibit tunability of optoelectronic properties similar to that of the group III nitrides, while comprising earth‐abundant and potentially low‐cost elements. However, the II‐IV nitrides synthesis is immature, limiting the explorations. Herein, ZnSnN2 hetero‐epitaxial films grown by high‐power impulse magnetron sputtering, having the quality at the level of the III‐nitrides layers grown without dislocation‐reducing strategies are demonstrated. This breakthrough, in addition to paving the way toward potential applications, enables reliable measurements of the ZnSnN2 properties in real space and k‐space. In particular, for wurtzite ZnSnN2 films with total dislocation density of ≤ 5 × 1010 cm−2, the lattice parameters and the optical band gap (Eg) are determined with the accuracy not being accessible before for this material, e.g. Eg = 1.67 ± 0.03 eV. Thus, looking retrospectively, the authors' data set the ZnSnN2—and perhaps more generally the II‐IV nitrides—at the stage comparable to that of the beginning of the III‐nitrides rising era. [ABSTRACT FROM AUTHOR]

Published
2021
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40. Homoepitaxial growth of beta-Ga2O3 layers by metal-organic vapor phase epitaxy

Author

Wagner, Guenter, Baldini, Michele, Gogova, Daniela, Schmidbauer, Martin, Schewski, Robert, Albrecht, Martin, Galazka, Zbigniew, Klimm, Detlef, and Fornari, Roberto

Subjects
Ga2O3, transparent semiconducting oxides, thin films, metal-organic vapor phase epitaxy, structure
Abstract

Epitaxial -Ga2O3 layers have been grown on -Ga2O3 (100) substrates using metal-organic vapor phase epitaxy. Trimethylgallium and pure oxygen or water were used as precursors for gallium and oxygen, respectively. By using pure oxygen as oxidant, we obtained nano-crystals in form of wires or agglomerates although the growth parameters were varied in wide range. With water as an oxidant, smooth homoepitaxial -Ga2O3 layers were obtained under suitable conditions. Based on thermodynamical considerations of the gas phase and published ab initio data on the catalytic action of the (100) surface of -Ga2O3 we discuss the adsorption and incorporation processes that promote epitaxial layer growth. The structural properties of the -Ga2O3 epitaxial layers were characterized by X-ray diffraction pattern and high resolution transmission electron microscopy. As-grown layers exhibited sharp peaks that were assigned to the monocline gallium oxide phase and odd reflections that could be assigned to stacking faults and twin boundaries, also confirmed by TEM. Shifts of the layer peak towards smaller 2 values with respect to the Bragg reflection for the bulk peaks have been observed. After post growth thermal treatment in oxygen-containing atmosphere the reflections of the layers do shift back to the position of the bulk -Ga2O3 peaks, which was attributed to significant reduction of lattice defects in the grown layers after thermal treatment. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Published
2014

43. Epitaxial stabilization of pseudomorphic α-Ga2O3on sapphire (0001)

Author

Schewski, Robert, primary, Wagner, Günter, additional, Baldini, Michele, additional, Gogova, Daniela, additional, Galazka, Zbigniew, additional, Schulz, Tobias, additional, Remmele, Thilo, additional, Markurt, Toni, additional, von Wenckstern, Holger, additional, Grundmann, Marius, additional, Bierwagen, Oliver, additional, Vogt, Patrick, additional, and Albrecht, Martin, additional

Published
2014
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50. A new approach to free-standing GaN using β-Ga2O3 as a substrate

Author

Kachel, Krzysztof, primary, Korytov, Maxim, additional, Gogova, Daniela, additional, Galazka, Zbigniew, additional, Albrecht, Martin, additional, Zwierz, Radoslaw, additional, Siche, Dietmar, additional, Golka, Sebastian, additional, Kwasniewski, Albert, additional, Schmidbauer, Martin, additional, and Fornari, Roberto, additional

Published
2012
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