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48 results on '"Orekhov, Anton S."'

3. Coulomb blockade in field electron emission from carbon nanotubes

Author

Kleshch, Victor I., Porshyn, Vitali, Serbun, Pavel, Orekhov, Anton S., Ismagilov, Rinat R., Malykhin, Sergey A., Eremina, Valentina A., Obraztsova, Elena D., Lützenkirchen-Hecht, Dirk, and Obraztsov, Alexander N.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We report the observation of Coulomb blockade in field electron emission (FE) from single-wall carbon nanotubes (SWCNTs), which is manifested as pronounced steps in the FE current-voltage curves and oscillatory variations in the energy distribution of emitted electrons. The appearance of the Coulomb blockade is explained by the formation of nanoscale protrusions at the apexes of SWCNTs due to the electric field-assisted surface diffusion of adsorbates and carbon adatoms. The proposed adsorbate-assisted FE mechanism is substantially different from the well-known resonant tunneling associated with discrete electronic states of adsorbed atoms. The simulations based on the Coulomb blockade theory are in excellent agreement with the experimental results. The SWCNT field emitters controlled by the Coulomb blockade effect are expected to be used to develop on-demand coherent single-electron sources for advanced vacuum nanoelectronic devices., Comment: 19 pages, 8 figures

Published
2020
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4. Coulomb-blockade-controlled single-electron point source

Author

Kleshch, Victor I., Porshyn, Vitali, Orekhov, Anton S., Orekhov, Andrey S., Lützenkirchen-Hecht, Dirk, and Obraztsov, Alexander N.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Coulomb blockade is a fundamental phenomenon in physics enabling transfer of individual electrons one by one into electrically isolated nanostructures such as nanowires or quantum dots and thereby creation of sources of single electrons. Nowadays, solid-state single-electron sources are key elements of the emerging new technologies of quantum information processing and single-electron electronics. Moreover, advanced research in free-electron quantum optics and developments in electron microscopy require the point sources of free electrons in vacuum, which can be controlled on a single electron level. However, up to now, single-electron vacuum guns were not realized in practice. The problems to be solved include the formation of stable tip-shaped heterostructured emitters and control of liberated electrons in time and energy domain. Here we overcome these challenges by creating a field emission (FE) electron source based on a carbon nanowire coupled to an ultra-sharp diamond tip by a tunnel junction. Using energy spectroscopy, we directly observe Coulomb oscillations of the electron Fermi level in the nanowire at room temperature and FE currents up to 1 $\mu$A. We reveal that the oscillations are suppressed at high FE current either by Joule heating or due to the high tunneling resistance, depending on the nanowire charging time, ranging from about 25 fs to 1 ps. We anticipate that the combination of introduced carbon single-electron sources with laser-induced gating is highly promising for the creation of coherent ultrashort free-electron bunches of interest for low-energy electron holography and ultrafast electron or X-ray imaging and spectroscopy., Comment: 25 pages, 10 figures

Published
2020

24. Coulomb blockade in field electron emission from carbon nanotubes

Author

Kleshch, Victor I., primary, Porshyn, Vitali, additional, Serbun, Pavel, additional, Orekhov, Anton S., additional, Ismagilov, Rinat R., additional, Malykhin, Sergey A., additional, Eremina, Valentina A., additional, Obraztsov, Petr A., additional, Obraztsova, Elena D., additional, and Lützenkirchen-Hecht, Dirk, additional

Published
2021
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26. Low-resolution structures of modular nanotransporters shed light on their functional activity

Author

Khramtsov, Yuri V., primary, Vlasova, Anastasiia D., additional, Vlasov, Alexey V., additional, Rosenkranz, Andrey A., additional, Ulasov, Alexey V., additional, Ryzhykau, Yury L., additional, Kuklin, Alexander I., additional, Orekhov, Anton S., additional, Eydlin, Ilia B., additional, Georgiev, Georgii P., additional, Gordeliy, Valentin I., additional, and Sobolev, Alexander S., additional

Published
2020
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28. Highly oriented graphite produced by femtosecond laser on diamond

Author

Kononenko, Vitali V., primary, Khomich, Andrej A., additional, Khomich, Alexander V., additional, Khmelnitskii, Roman A., additional, Gololobov, Viktor M., additional, Komlenok, Maxim S., additional, Orekhov, Andrey S., additional, Orekhov, Anton S., additional, and Konov, Vitaly I., additional

Published
2019
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29. Protective Dps–DNA co‐crystallization in stressed cells: an in vitro structural study by small‐angle X‐ray scattering and cryo‐electron tomography

Author

Dadinova, Liubov A., primary, Chesnokov, Yurii M., additional, Kamyshinsky, Roman A., additional, Orlov, Ivan A., additional, Petoukhov, Maxim V., additional, Mozhaev, Andrey A., additional, Soshinskaya, Ekaterina Yu., additional, Lazarev, Vassili N., additional, Manuvera, Valentin A., additional, Orekhov, Anton S., additional, Vasiliev, Alexander L., additional, and Shtykova, Eleonora V., additional

Published
2019
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35. Carbon superfine materials as a promising material for Gluconobacter oxydans based microbial fuel cells

Author

Tenchurin, Timur K, primary, Reshetilov, Anatoly N, additional, Plekhanova, Yuliya V, additional, Tarasov, Sergey E, additional, Bykov, Aleksandr G, additional, Gutorov, Michail A, additional, Alferov, Sergey V, additional, Chvalun, Sergei N, additional, Orekhov, Anton S, additional, Shepelev, Alexey D, additional, Gotovtsev, Pavel M, additional, and Vasilov, Raif G, additional

Published
2018
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42. Wormlike Surfactant Micelles with Embedded Polymer Chains

Author

Kwiatkowski, Alexander L., Sharma, Hari, Molchanov, Vyacheslav S., Orekhov, Anton S., Vasiliev, Alexander L., Dormidontova, Elena E., and Philippova, Olga E.

Abstract

Active use of wormlike micelle (WLM) solutions in a broad range of applications demands control of their viscoelastic properties under different external conditions that can be achieved by using hybrid materials, such as polymer–surfactant complexes. Understanding the properties of such hybrid materials remains a challenge. Using a combination of several experimental techniques with molecular dynamics simulations, we investigate the interaction of poly(4-vinylpyridine) with WLMs of the anionic surfactant potassium oleate. We find that this polymer is solubilized by the micelles at the interface between the tails and headgroups of surfactant, thus screening the hydrophobic polymer backbone from interactions with water while maintaining hydrogen bonding between the pyridine rings and water. By use of SANS with contrast variation, it was shown that the macromolecules associated with the micelles have an expanded coil-like conformation with persistence length 4-fold higher than that of a polymer chain in a good solvent. The rheological behavior of the micellar solutions shows that at low polymer concentrations (regime I) the system maintains high viscoelasticity with the plateau modulus remaining almost unchanged, while the zero-shear viscosity slightly decreases. At higher polymer concentrations (regime II), the viscosity drops by more than 4 orders of magnitude, approaching that of pure solvent. The transition from the I to II regime occurs when the number of added macromolecules is approximately equal to the number of elastically active strands in micellar network. The observed changes are attributed to polymer-induced shortening of WLMs accompanied by loop and branch formation. The saturated polymer–surfactant complex contains about one surfactant per repeat unit of the polymer and represents a best compromise when the WLM retains its general cylindrical geometry (but not the viscoelastic properties) and the polymer maintains an expanded coil-like conformation.

Published
2024
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44. A Comparative Study of Field Emission From Semiconducting and Metallic Single‐Walled Carbon Nanotube Planar Emitters.

Author

Kleshch, Victor I., Eremina, Valentina A., Serbun, Pavel, Orekhov, Anton S., Lützenkirchen‐Hecht, Dirk, Obraztsova, Elena D., and Obraztsov, Alexander N.

Subjects
SINGLE walled carbon nanotubes, ELECTRON field emission, SEMICONDUCTORS, THIN films, TWO-phase flow
Abstract

Field electron emission from thin films composed of solely metallic or semiconducting single‐walled carbon nanotubes is investigated using a scanning tip anode technique. Metallic and semiconducting nanotubes are separated by aqueous two‐phase extraction. Local field emission centers observed on nanotube films of both types showed non‐linear Fowler–Nordheim (FN) plots bent downwards. The curving of FN plots is much stronger for semiconducting nanotubes which is explained by their higher electrical resistance and stronger field penetration effect compared to metallic nanotubes. Particular nanotubes of both types revealed oscillations in current–voltage characteristics. The periodic oscillations indicated that the field emission current is modulated either by resonant tunnelling from confinement states in nano‐objects formed by adsorbates or by the Coulomb blockade effect that can occur for emission from short carbon nanotubes. [ABSTRACT FROM AUTHOR]

Published
2018
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45. Luminescent Characteristics of Needle‐Like Single Crystal Diamonds.

Author

Malykhin, Sergey A., Houard, Jonathan, Ismagilov, Rinat R., Orekhov, Anton S., Vella, Angela, and Obraztsov, Alexander N.

Subjects
DIAMOND crystals, SINGLE crystals, PHOTON-electron interactions, LUMINESCENCE spectroscopy, WAVELENGTHS
Abstract

Luminescent properties of needle‐like single crystal diamonds are investigated in a wide range of wavelength. The luminescent spectra with zero phonon lines centered at 389, 442, 468, 534, 563, 575, and 738 nm are detected using excitation by photons and electrons. Obtained photo‐ and cathodo‐luminescent (PL and CL) spectra indicate presence in the single‐crystal diamond needles of nitrogen‐ and silicon‐vacancy centers as well as substitutional or/and interstitials related to these atomic impurities. The dependencies of PL intensities of the 575 and 738 nm lines (related, correspondingly, to nitrogen‐ and silicon‐vacancy centers) on excitation wavelength are determined. Time‐resolved measurements are performed for the 575 nm PL line. The luminescence decay behavior for this line demonstrates the presence of recombination processes with characteristic times of about 28 ns (on 200 ns time scale) and 2.8 ns (on 20 ns time scale). [ABSTRACT FROM AUTHOR]

Published
2018
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46. Two-Ply Composite Membranes with Separation Layers from Chitosan and Sulfoethylcellulose on a Microporous Support Based on Poly(diphenylsulfone-N-phenylphthalimide).

Author

Kononova, Svetlana V., Kruchinina, Elena V., Petrova, Valentina A., Baklagina, Yulia G., Romashkova, Kira A., Orekhov, Anton S., Klechkovskaya, Vera V., and Skorik, Yury A.

Subjects
POLYMERIC membranes, CHITOSAN, ETHYLCELLULOSE, MICROPOROSITY, SULFONE derivatives, PHTHALIMIDES, X-ray diffraction
Abstract

Two-ply composite membranes with separation layers from chitosan and sulfoethylcellulose were developed on a microporous support based on poly(diphenylsulfone-N-phenylphthalimide) and investigated by use of X-ray diffraction and scanning electron microscopy methods. The pervaporation properties of the membranes were studied for the separation of aqueous alcohol (ethanol, propan-2-ol) mixtures of different compositions. When the mixtures to be separated consist of less than 15 wt % water in propan-2-ol, the membranes composed of polyelectrolytes with the same molar fraction of ionogenic groups (-NH3+ for chitosan and -SO3- for sulfoethylcellulose) show high permselectivity (the water content in the permeate was 100%). Factors affecting the structure of a non-porous layer of the polyelectrolyte complex formed on the substrate surface and the contribution of that complex to changes in the transport properties of membranes are discussed. The results indicate significant prospects for the use of chitosan and sulfoethylcellulose for the formation of highly selective pervaporation membranes. [ABSTRACT FROM AUTHOR]

Published
2017
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47. Structure and optical properties of thin poly(p-xylylene) – Silver nanocomposite films prepared by low-temperature vapor deposition polymerization

Author

Streltsov, Dmitry R., primary, Mailyan, Karen A., additional, Gusev, Alexey V., additional, Ryzhikov, Ilya A., additional, Kiryukhin, Yury I., additional, Orekhov, Anton S., additional, Vasiliev, Alexander L., additional, Erina, Natalia A., additional, Pebalk, Andrey V., additional, Odarchenko, Yaroslav I., additional, Chvalun, Sergei N., additional, and Ivanov, Dimitri A., additional

Published
2015
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