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Мигас, Дмитрий Борисович

Организационные подразделения

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Институт нанотехнологий в электронике, спинтронике и фотонике

Институт ИНТЭЛ занимается научной деятельностью и подготовкой специалистов в области исследования физических принципов, проектирования и разработки технологий создания компонентной базы электроники гражданского и специального назначения, а также построения современных приборов на её основе. Наша основная цель – это создание и развитие научно-образовательного центра мирового уровня в области наноструктурных материалов и устройств электроники, спинтроники, фотоники, а также создание эффективной инновационной среды в области СВЧ-электронной и радиационно-стойкой компонентной базы, источников ТГц излучения, ионно-кластерных технологий материалов.

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Мигас

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Дмитрий Борисович

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Теперь показываю 1 - 10 из 30

Только метаданные
Marked enhancement of the photoresponsivity and minority-carrier lifetime of BaS i2 passivated with atomic hydrogen
(2019) Xu, Z.; Shohonov, D. A.; Filonov, A. B.; Gotoh, K.; Migas, D. B.; Borisenko, V. E.; Мигас, Дмитрий Борисович
© 2019 American Physical Society.Passivation of barium disilicide (BaSi2) films is very important for their use in solar cell applications. In this paper, we demonstrated the effect of hydrogen (H) passivation on both the photoresponsivity and minority-carrier lifetime of BaSi2 epitaxial films grown by molecular beam epitaxy. First, we examined the growth conditions of a 3-nm-thick hydrogenated amorphous silicon (a-Si) capping layer formed on a 500-nm-thick BaSi2 film and found that an H supply duration (ta-Si:H) of 15 min at a substrate temperature of 180 °C sizably enhanced the photoresponsivity of the BaSi2 film. We next supplied atomic H to BaSi2 epitaxial films at 580 °C and changed supply duration (tBaSi;H) in the range of 1-30 min, followed by capping with an a-Si layer. The photoresponsivity of the films changed considerably depending on tBaSi;H and reached a maximum of 2.5 A/W at a wavelength of 800 nm for the sample passivated for tBaSi;H=15 min under a bias voltage of 0.3 V applied to the front-surface indium-tin-oxide electrode with respect to the back-surface aluminum electrode. This photoresponsivity is approximately one order of magnitude higher than the highest value previously reported for BaSi2. Microwave photoconductivity decay measurements revealed that the minority-carrier lifetime of the BaSi2 film with the highest photoresponsivity was 14 μs, equivalent to its bulk carrier lifetime ever reported. We performed theoretical analyses based on a rate equation including several recombination mechanisms and reproduced the experimentally obtained decay curves. We also calculated the total density of states of BaSi2 by ab initio studies when one Si vacancy existed in a unit cell and one, two, and three H atoms occupied Si vacancy or interstitial sites. A Si vacancy caused a localized state with two energy bands to appear close to the middle of the band gap. In certain cases, H passivation of the Si dangling bonds can markedly decrease trap concentration. From both experimental and theoretical viewpoints, we conclude that an atomic H supply is beneficial for BaSi2 solar cells.
Только метаданные
Mechanisms of carrier lifetime enhancement and conductivity-type switching on hydrogen-incorporated arsenic-doped BaSi2
(2021) Aonuki, S.; Xu, Z.; Yamashita, Y.; Gotoh, K.; Migas, D. B.; Мигас, Дмитрий Борисович
© 2021 Elsevier B.V.A comparative experimental and theoretical study of the role of H incorporation in As-doped BaSi2 films has been carried out based on the experimental results that an optimal time of H treatment for the increase in photoresponsivity and carrier lifetime was in the range of 1 – 20 min. Adequate theoretical representation of the decay curves in the framework of the model for non-radiative processes accounted for various trap-related recombination mechanisms to estimate the trap concentration to be in the range of 1.9 × 1013 to 1.7 × 1014 cm−3. Additionally, the extended theoretical ab initio quantum-chemical simulation of the electronic structure of the studied systems was performed. It was revealed that interstitial As atoms can mostly provide trap states in the gap while H atoms neutralize such traps. The experimentally observed unexpected switching in conductivity from n-type to p-type and vice versa in As-doped BaSi2 with H incorporation was explained to specific configurations of point defects (an As impurity with a H atom in different positions and various interatomic As-H distances) which affect the position of states in the gap.
Только метаданные
Stability of 2D Alkaline-Earth Metal Silicides, Germanides and Stannides
(2019) Alekseev, A. Yu.; Chernykh, A. G.; Filonov, A. B.; Skorodumova, N. V.; Migas, D. B.; Мигас, Дмитрий Борисович
By means of ab initio calculations, we have estimated stability of 2D Me2X (Me = Mg, Ca, Sr, Ba and X = Si, Ge, Sn) in the T and Td phases, which are similar to the ones of 2D transition metal chalcogenides, in addition to their phonon spectra. The T phase is found to be more stable for 2D Ca2X, Sr2X and Ba2X, whereas the Td phase is predicted to be the ground state for 2D Mg2X. We have also discussed that imaginary frequencies in the calculated phonon spectra of 2D Me2X, which appeared in the vicinity of the Gamma point, were not necessarily associated with the dynamic instability.
Только метаданные
New monoclinic ground state of FeSi
(2024) Galkin, N. G.; Migas, D. B.; Medvedeva, N. V.; Filonov, A. B.; Мигас, Дмитрий Борисович
Только метаданные
Crystal Structure, Optical Properties, and Characteristics of the Band Gap of Ca2Si Semiconductor Films on an Al2O3(0001) Substrate
(2022) Galkin, N. G.; Galkin, K. N.; Chernev, I. M.; Kropachev, O. V.; Goroshko, D. L.; Subbotin, E. Y.; Migas, D. B.; Мигас, Дмитрий Борисович
Только метаданные
Ultra-thin and thin CrSi films on Si(111): II. Transport and magnetic properties
(2024) Galkin, N. G.; Subbotin, E. Yu.; Galkin, K. N.; Migas, D. B.; Мигас, Дмитрий Борисович
Только метаданные
The origin of different iridium oxidation states of Sr2IrO4
(2025) Migas, D. B.; Filonov, A. B.; Daniluyk, A. L.; Skorodumova, N. V.; Мигас, Дмитрий Борисович
Только метаданные
Recent Progress Toward Realization of High-Efficiency BaSi2 Solar Cells: Thin-Film Deposition Techniques and Passivation of Defects
(2022) Suemasu, T.; Migas, D. B.; Мигас, Дмитрий Борисович
© 2021 Wiley-VCH GmbHSafe, stable, and earth-abundant materials for solar cell applications are of particular importance to realize a decarbonized society. Semiconducting barium disilicide (BaSi2), which is composed of nontoxic and earth-abundant elements, is an emerging material to meet this requirement. BaSi2 has a bandgap of 1.3 eV that is suitable for single-junction solar cells, a large absorption coefficient exceeding that of chalcopyrite, and inactive grain boundaries. This review is started by describing the recent progress of BaSi2 thin-film deposition techniques using radio-frequency sputtering and discuss the high photoresponsivity of BaSi2 thin films. Special attention is paid to passivation of the defects in BaSi2 films by hydrogen or carbon doping. Ab initio studies based on density-functional theory are then used to calculate the positions of the localized defective states and the Fermi level to discuss the experimentally obtained passivation effects. Finally, the issues that need to be resolved toward realization of high-efficiency BaSi2 solar cells are addressed.
Только метаданные
Effects of Si/Ge superlattice structure with intermixed interfaces on phonon thermal conductivity
(2025) Khamets, A. L.; Safronov, I. V.; Filonov, A. B.; Migas, D. B.; Мигас, Дмитрий Борисович
Только метаданные
Structural stability and electronic properties of 2D alkaline-earth metal silicides, germanides, and stannides
(2020) Alekseev, A. Y.; Migas, D. B.; Filonov, A. B.; Borisenko, V. E.; Мигас, Дмитрий Борисович
We present the results of an extended theoretical study of the structure, phonon, electronic and optical properties of 2D alkaline-earth metal silicides, germanides and stannides (2D Me2X, where Me=Mg, Ca, Sr, Ba and X=Si, Ge, Sn). The performed analysis has shown the occurrence of the pseudo passivation effect and ionic chemical bonding in these 2D Me2X. In addition, the preformed investigation of their phonon spectra has shown the absence of imaginary frequencies indicating the stability of these 2D structures. The band structure calculations performed using the hybrid functional have revealed that all 2D Me2X are semiconductors with the gap varying from 0.12 to 1.01 eV. Among them Mg- and Ca-based 2D materials are direct band-gap semiconductors with the first direct transition having appreciable oscillator strength. We also propose to consider ternary 2D silicides, germanides and stannides with different Me atoms as a feasible way to modify properties of parent 2D Me2X. (c) 2020 The Japan Society of Applied Physics