Alexander Lebedev - Academia.edu (original) (raw)
Papers by Alexander Lebedev
Materials Science and Engineering: B, 1997
The objective of the present work was to prepare heterojunctions in the 3C-6H system and to inves... more The objective of the present work was to prepare heterojunctions in the 3C-6H system and to investigate their characteristics. The heteroepitaxy was carried out using sublimation epitaxy (SE) in an open system. The presence of 3C-Sic in the deposited structures was confirmed by X-ray diffraction. The p-n junction parameters were investigated from current-voltage and capacitance-voltage measurements, electroluminescence spectrum and DLTS data. 0 1997 Published by Elsevier Science S.A.
Materials Science Forum, 2011
Materials Science Forum, 2010
Within the scope of the Harrison's bond orbital model the spontaneous polarization, high-and low ... more Within the scope of the Harrison's bond orbital model the spontaneous polarization, high-and low frequency dielectric constants are obtained in an analytical form. Theoretical results are in a reasonable agreement with the experimental data available and the numerical calculations based on the ab initio methods.
Materials Science Forum, 2010
Nonequilibrium-charge transport has been studied in a structure with a Schottky barrier fabricate... more Nonequilibrium-charge transport has been studied in a structure with a Schottky barrier fabricated on a CVD-grown n-4H-SiC film. The charge introduced by single α-particles was recorded by nuclear spectrometric techniques. The maximum electric field strength in the structure was 1.1 MV/cm. The recorded charge as a function of the reverse bias applied to the structure shows a superlinear rise. Simultaneously, the width of the amplitude spectrum increased superlinearly, too. The observed effect is attributed to the initial stage of impact ionization. The manifestation of the process at unusually low fields (~1.0 MV/cm) is accounted for by specific features of the charge generation process. The carriers generated by a α-particle are found to be originally "heated". The results obtained allow prognostication of the appearance of SiC detectors of the "proportional counter" type in the near future. This is enabled by the advances made in the field of high-voltage electronics in obtaining in practice the required electric field strengths.
Materials Science Forum, 2013
ABSTRACT Abstract Results of an epitaxial growth of 3C-SiC epilayers on Si (0001) and C(000¯1) fa... more ABSTRACT Abstract Results of an epitaxial growth of 3C-SiC epilayers on Si (0001) and C(000¯1) faces of hexagonal 6H-SiC substrates are described. TEM study of grown layers as well as interface between cubic and hexagonal polytypes is presented. Difference between the layers on the Si and C faces are discussed.
Materials Science Forum, 2013
ABSTRACT Transport properties of multigraphene layers on 6H-SiC substrates was studied. It was fo... more ABSTRACT Transport properties of multigraphene layers on 6H-SiC substrates was studied. It was found that the curves of magnetoresistance and Shubnikov- de Haas oscillations shown the features, typical for single-layred graphene. The low temperature resistance demonstrated an increase with temperature increase, which also corresponds to a behavior typical for single-layered graphene (antilocalization). However at higher temperatures the resistance decreased with an increase of temperature, which corresponds to a weak localization. We believe that the observed behavior can be explained by a parallel combination of contributions to the conductivity of single-layered graphene and of multigraphene.
Materials Science Forum, 2010
Page 1. Low Temperature near band gap photoluminescence of 3C-SiC/15R-SiC and 3C-SiC/6H-SiC heter... more Page 1. Low Temperature near band gap photoluminescence of 3C-SiC/15R-SiC and 3C-SiC/6H-SiC heterostructures AALebedev, PLAbramov, EVBogdanova, S.Yu.Davydov, SPLebedev, DKNelson, GAOganesyan, BSRazbirin, ASTregubova. ...
Materials Science Forum, 2010
... 3C SiC epilayers (of 15 µm and 42 µm thickness) were grown by sublimation epitaxy on differen... more ... 3C SiC epilayers (of 15 µm and 42 µm thickness) were grown by sublimation epitaxy on different SiC substrates: either on Si-face of 6H Lely n-type substrate with d− a = (3÷4)×10 18 cm -3 (sample ... Page 2. No.1, β1) or on C-face of 15R Lely n-type substrate with n0 = (1÷2)×10 ...
Materials Science Forum, 2012
The polarization effect characteristically occurs in detectors based on wide-bandgap materials at... more The polarization effect characteristically occurs in detectors based on wide-bandgap materials at considerable concentrations of radiation defects. The appearance of an electromotive force in the bulk of a detector is due to the long-term capture of carriers at deep levels related to radiation centers. The kinetics and strength of the polarization field have been determined. The capture can be controlled by varying the detector temperature, with a compromise reached at the "optimal" temperature between the generation current and the position of the deepest of the levels whose contribution to the loss of charge via capture is negligible. It has been found that the depth of a level (related to the energy gap width) is close to 1/3, irrespective of the material. The optimal temperatures are specific to individual materials.
Materials Science Forum, 2013
The irradiation with 0.9 MeV electrons and with 8 MeV and 15 MeV protons were performed for study... more The irradiation with 0.9 MeV electrons and with 8 MeV and 15 MeV protons were performed for studying radiation defects. Proton scattering in a silicon carbide film has been numerically simulated. Distribution histograms of the energy imparted to recoil atoms are obtained. Two energy ranges are considered when analyzing the histograms. In the first range of "low" energies, individual Frenkel pairs with closely spaced components are created. In the second range, recoil atoms have energies sufficient for generating a cascade of displacements. This gives rise to microscopic regions with high density of vacancies and vacancy complexes of various kinds. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 194.85.224.35, Russian Academy of Sciences, St. Petersburg, Russian Federation-19/03/13,12:40:24)
Materials Science Forum, 2011
ABSTRACT Influence of high-vacuum annealing at temperatures in the range 1300-1400°C and residual... more ABSTRACT Influence of high-vacuum annealing at temperatures in the range 1300-1400°C and residual pressure of ~10-6 Torr on the surface of 6H-SiC (0001) wafers has been studied. Auger spectroscopy and RHEED data show that the annealing conditions do not lead to any surface reconstruction of the wafers. Atomic force microscopy reveals atomically flat surface terraces separated by steps of unit-cell height (h = 1.5 nm).
Materials Science Forum, 2010
ABSTRACT Atomic-force microscopy and scanning tunnel electron microscopy have been used to study ... more ABSTRACT Atomic-force microscopy and scanning tunnel electron microscopy have been used to study the surface of single-crystal 6H-SiC (0001) substrates subjected to step-by-step high-temperature annealing in vacuum. An annealing procedure leading to surface structuring by atomically smooth steps with heights of 0.75 and 1.5 nm has been found. It is suggested to use the structured surfaces as test objects for z-calibration of scanning probe microscopes.
Materials Science Forum, 2012
ABSTRACT The analytical expression for the density-of-states (DOS) of single-layer graphene inter... more ABSTRACT The analytical expression for the density-of-states (DOS) of single-layer graphene interacting with the SiC surface (epitaxial graphene) is obtained. The silicon carbide DOS is described within the scope of the Haldane-Anderson model. It is shown that due to the interaction with the substrate the gap of about 0.01-0.06 eV arises in the epitaxial graphene DOS. The estimation indicates that the electron charge of about (−10-3) e/atom transfers from the substrate to graphene.
Materials Science Forum, 2013
ABSTRACT The simple model for the one-layer graphene energy gaps induced by the substrate energy ... more ABSTRACT The simple model for the one-layer graphene energy gaps induced by the substrate energy gap is pro-posed.
Materials Science Forum, 2011
Page 1. On Application of Sublimation Epitaxy to Growth of Bulk 3C-SiC Crystals AA Lebedev, PL Ab... more Page 1. On Application of Sublimation Epitaxy to Growth of Bulk 3C-SiC Crystals AA Lebedev, PL Abramov, AS Zubrilov, EV Bogdanova, SP Lebedev, NV Seredova, and AS Tregubova. Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. ...
Materials Science Forum, 2014
Physica B: Condensed Matter, 2009
a b s t r a c t 3C-SiC epitaxial layers were grown by sublimation epitaxy in a vacuum on the (000... more a b s t r a c t 3C-SiC epitaxial layers were grown by sublimation epitaxy in a vacuum on the (0001)C face of 6H-SiC substrates produced by the Lely method and 4H-SiC substrates grown by modified Lely method. An analysis of these layers demonstrated the high structural perfection of the epitaxial layers and absence of any transition regions between 3C-SiC epitaxial layer and substrate. The low-temperature conductivity and magnetoresistance of the films have been studied in relation to their doping level and structural perfection.
Journal of Materials Science: Materials in Electronics, 2008
Abstract In this study, we carried out for the first time a galvanomagnetic investigation of 3CS... more Abstract In this study, we carried out for the first time a galvanomagnetic investigation of 3CSiC/6HSiC hetero-structures at liquid-helium temperatures and observed in n-3CSiC low resistance of the samples and the appearance of a negative magnetoresistance in ...
Materials Science and Engineering: B, 1997
The objective of the present work was to prepare heterojunctions in the 3C-6H system and to inves... more The objective of the present work was to prepare heterojunctions in the 3C-6H system and to investigate their characteristics. The heteroepitaxy was carried out using sublimation epitaxy (SE) in an open system. The presence of 3C-Sic in the deposited structures was confirmed by X-ray diffraction. The p-n junction parameters were investigated from current-voltage and capacitance-voltage measurements, electroluminescence spectrum and DLTS data. 0 1997 Published by Elsevier Science S.A.
Materials Science Forum, 2011
Materials Science Forum, 2010
Within the scope of the Harrison's bond orbital model the spontaneous polarization, high-and low ... more Within the scope of the Harrison's bond orbital model the spontaneous polarization, high-and low frequency dielectric constants are obtained in an analytical form. Theoretical results are in a reasonable agreement with the experimental data available and the numerical calculations based on the ab initio methods.
Materials Science Forum, 2010
Nonequilibrium-charge transport has been studied in a structure with a Schottky barrier fabricate... more Nonequilibrium-charge transport has been studied in a structure with a Schottky barrier fabricated on a CVD-grown n-4H-SiC film. The charge introduced by single α-particles was recorded by nuclear spectrometric techniques. The maximum electric field strength in the structure was 1.1 MV/cm. The recorded charge as a function of the reverse bias applied to the structure shows a superlinear rise. Simultaneously, the width of the amplitude spectrum increased superlinearly, too. The observed effect is attributed to the initial stage of impact ionization. The manifestation of the process at unusually low fields (~1.0 MV/cm) is accounted for by specific features of the charge generation process. The carriers generated by a α-particle are found to be originally "heated". The results obtained allow prognostication of the appearance of SiC detectors of the "proportional counter" type in the near future. This is enabled by the advances made in the field of high-voltage electronics in obtaining in practice the required electric field strengths.
Materials Science Forum, 2013
ABSTRACT Abstract Results of an epitaxial growth of 3C-SiC epilayers on Si (0001) and C(000¯1) fa... more ABSTRACT Abstract Results of an epitaxial growth of 3C-SiC epilayers on Si (0001) and C(000¯1) faces of hexagonal 6H-SiC substrates are described. TEM study of grown layers as well as interface between cubic and hexagonal polytypes is presented. Difference between the layers on the Si and C faces are discussed.
Materials Science Forum, 2013
ABSTRACT Transport properties of multigraphene layers on 6H-SiC substrates was studied. It was fo... more ABSTRACT Transport properties of multigraphene layers on 6H-SiC substrates was studied. It was found that the curves of magnetoresistance and Shubnikov- de Haas oscillations shown the features, typical for single-layred graphene. The low temperature resistance demonstrated an increase with temperature increase, which also corresponds to a behavior typical for single-layered graphene (antilocalization). However at higher temperatures the resistance decreased with an increase of temperature, which corresponds to a weak localization. We believe that the observed behavior can be explained by a parallel combination of contributions to the conductivity of single-layered graphene and of multigraphene.
Materials Science Forum, 2010
Page 1. Low Temperature near band gap photoluminescence of 3C-SiC/15R-SiC and 3C-SiC/6H-SiC heter... more Page 1. Low Temperature near band gap photoluminescence of 3C-SiC/15R-SiC and 3C-SiC/6H-SiC heterostructures AALebedev, PLAbramov, EVBogdanova, S.Yu.Davydov, SPLebedev, DKNelson, GAOganesyan, BSRazbirin, ASTregubova. ...
Materials Science Forum, 2010
... 3C SiC epilayers (of 15 µm and 42 µm thickness) were grown by sublimation epitaxy on differen... more ... 3C SiC epilayers (of 15 µm and 42 µm thickness) were grown by sublimation epitaxy on different SiC substrates: either on Si-face of 6H Lely n-type substrate with d− a = (3÷4)×10 18 cm -3 (sample ... Page 2. No.1, β1) or on C-face of 15R Lely n-type substrate with n0 = (1÷2)×10 ...
Materials Science Forum, 2012
The polarization effect characteristically occurs in detectors based on wide-bandgap materials at... more The polarization effect characteristically occurs in detectors based on wide-bandgap materials at considerable concentrations of radiation defects. The appearance of an electromotive force in the bulk of a detector is due to the long-term capture of carriers at deep levels related to radiation centers. The kinetics and strength of the polarization field have been determined. The capture can be controlled by varying the detector temperature, with a compromise reached at the "optimal" temperature between the generation current and the position of the deepest of the levels whose contribution to the loss of charge via capture is negligible. It has been found that the depth of a level (related to the energy gap width) is close to 1/3, irrespective of the material. The optimal temperatures are specific to individual materials.
Materials Science Forum, 2013
The irradiation with 0.9 MeV electrons and with 8 MeV and 15 MeV protons were performed for study... more The irradiation with 0.9 MeV electrons and with 8 MeV and 15 MeV protons were performed for studying radiation defects. Proton scattering in a silicon carbide film has been numerically simulated. Distribution histograms of the energy imparted to recoil atoms are obtained. Two energy ranges are considered when analyzing the histograms. In the first range of "low" energies, individual Frenkel pairs with closely spaced components are created. In the second range, recoil atoms have energies sufficient for generating a cascade of displacements. This gives rise to microscopic regions with high density of vacancies and vacancy complexes of various kinds. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 194.85.224.35, Russian Academy of Sciences, St. Petersburg, Russian Federation-19/03/13,12:40:24)
Materials Science Forum, 2011
ABSTRACT Influence of high-vacuum annealing at temperatures in the range 1300-1400°C and residual... more ABSTRACT Influence of high-vacuum annealing at temperatures in the range 1300-1400°C and residual pressure of ~10-6 Torr on the surface of 6H-SiC (0001) wafers has been studied. Auger spectroscopy and RHEED data show that the annealing conditions do not lead to any surface reconstruction of the wafers. Atomic force microscopy reveals atomically flat surface terraces separated by steps of unit-cell height (h = 1.5 nm).
Materials Science Forum, 2010
ABSTRACT Atomic-force microscopy and scanning tunnel electron microscopy have been used to study ... more ABSTRACT Atomic-force microscopy and scanning tunnel electron microscopy have been used to study the surface of single-crystal 6H-SiC (0001) substrates subjected to step-by-step high-temperature annealing in vacuum. An annealing procedure leading to surface structuring by atomically smooth steps with heights of 0.75 and 1.5 nm has been found. It is suggested to use the structured surfaces as test objects for z-calibration of scanning probe microscopes.
Materials Science Forum, 2012
ABSTRACT The analytical expression for the density-of-states (DOS) of single-layer graphene inter... more ABSTRACT The analytical expression for the density-of-states (DOS) of single-layer graphene interacting with the SiC surface (epitaxial graphene) is obtained. The silicon carbide DOS is described within the scope of the Haldane-Anderson model. It is shown that due to the interaction with the substrate the gap of about 0.01-0.06 eV arises in the epitaxial graphene DOS. The estimation indicates that the electron charge of about (−10-3) e/atom transfers from the substrate to graphene.
Materials Science Forum, 2013
ABSTRACT The simple model for the one-layer graphene energy gaps induced by the substrate energy ... more ABSTRACT The simple model for the one-layer graphene energy gaps induced by the substrate energy gap is pro-posed.
Materials Science Forum, 2011
Page 1. On Application of Sublimation Epitaxy to Growth of Bulk 3C-SiC Crystals AA Lebedev, PL Ab... more Page 1. On Application of Sublimation Epitaxy to Growth of Bulk 3C-SiC Crystals AA Lebedev, PL Abramov, AS Zubrilov, EV Bogdanova, SP Lebedev, NV Seredova, and AS Tregubova. Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. ...
Materials Science Forum, 2014
Physica B: Condensed Matter, 2009
a b s t r a c t 3C-SiC epitaxial layers were grown by sublimation epitaxy in a vacuum on the (000... more a b s t r a c t 3C-SiC epitaxial layers were grown by sublimation epitaxy in a vacuum on the (0001)C face of 6H-SiC substrates produced by the Lely method and 4H-SiC substrates grown by modified Lely method. An analysis of these layers demonstrated the high structural perfection of the epitaxial layers and absence of any transition regions between 3C-SiC epitaxial layer and substrate. The low-temperature conductivity and magnetoresistance of the films have been studied in relation to their doping level and structural perfection.
Journal of Materials Science: Materials in Electronics, 2008
Abstract In this study, we carried out for the first time a galvanomagnetic investigation of 3CS... more Abstract In this study, we carried out for the first time a galvanomagnetic investigation of 3CSiC/6HSiC hetero-structures at liquid-helium temperatures and observed in n-3CSiC low resistance of the samples and the appearance of a negative magnetoresistance in ...