Papers by Author: Alexander A. Lebedev

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Authors: Alexander A. Lebedev, S.V. Belov, Marina G. Mynbaeva, Anatoly M. Strel'chuk, Elena V. Bogdanova, Yu.N. Makarov, A.S. Usikov, Sergey Kurin, I.S. Barash, Alexander D. Roenkov, Vitalii V. Kozlovski
Abstract: Schottky-barrier diodes with a diameter of ~10 μm are fabricated on n-GaN epitaxial films grown by hydride vapor-phase epitaxy (HVPE) on sapphire substrates. The changes in the parameters of the diodes under irradiation with 15 MeV protons are studied. The carrier rate was found to be 130-145 cm-1. The linear nature of the dependence N = F (D) (N is carrier concentration, and D, the irradiation dose) shows that compensation of the material is associated with transition of electrons from shallow donors to deep acceptor levels which are related to primary radiation defects.
Authors: Konstantin Vassilevski, A.V. Zorenko, Konstantinos Zekentes, Katerina Tsagaraki, Edwige Bano, C. Banc, Alexander A. Lebedev
Authors: Alexander M. Ivanov, Evgenia V. Kalinina, Nikita B. Strokan, Alexander A. Lebedev
Abstract: The spectrometric characteristics of detectors based on 4H-SiC films with ion-doped p+–n junctions in a temperature range from 25 to 375 °C have been studied. The experiments with 5.8-MeV α-particles in a high-temperature chamber were performed. The interference factors of the detectors operation in a mode of spectrometry are established. The energy resolution of 1.35% is received. An increase of the efficiency of the diffusion–drift charge transport with increasing temperature has been observed. The last is explained by an increase in the diffusion length of minority carriers.
Authors: Anatoly M. Strel'chuk, Alexander A. Lebedev, A.E. Cherenkov, Alexey N. Kuznetsov, Alla S. Tregubova, M.P. Scheglov, L.M. Sorokin, S. Yoneda, Shigehiro Nishino
Abstract: Investigation of the multilayer 6H(n+)/3C(n)/6H(p+)-SiC heterostructure grown by sublimation epitaxy show that the injection electroluminescence (IEL) in the green region (hνmax≈2.30-2.35eV) of spectrum is dominant. This band is close to the electroluminescence peak due to defects in 6H-SiC but also can be due to free exciton annihilation in a quantum well in 3C-SiC at the 6H/3C-SiC heterointerface. At high current the IEL peak at hνmax≈2.9 eV is found. This peak (and also two another peaks in blue part of spectra: hνmax≈2.6 eV and hνmax≈2.72 eV) can be attributed to recombination in 6H-SiC. The forward current-voltage characteristics for best structures are close to those for ideal 6H-SiC pn homostructure and characterized by abrupt breakdown. A lot of structures are characterized by barrier type excess current. Structure in the region of evident 3C-SiC inclusion is characterized by high forward and reverse excess currents.
Authors: M. Badila, Gheorghe Brezeanu, Jean-Pierre Chante, Marie Laure Locatelli, José Millan, Phillippe Godignon, Alexander A. Lebedev, P. Lungu, V. Banu
Authors: Gheorghe Brezeanu, M. Badila, José Millan, Phillippe Godignon, Marie Laure Locatelli, Jean-Pierre Chante, Alexander A. Lebedev, V. Banu
Authors: Anatoly M. Strel'chuk, A.V. Mashichev, Alexander A. Lebedev, A.N. Volkova, Konstantinos Zekentes
Abstract: The forward current was investigated in 4H-SiC p+n structures grown by sublimation epitaxy. The doping level, Nd-Na, of the n-layer was about (3-4)x1016 cm-3 and the diode area was in the range from 1x10-5 to 2x10-4 cm2. The observed current can be considered as current due to bulk recombination in the space charge region of the pn junction via deep level center or due to surface recombination. The criterion which was performed in this study to differentiate such currents was the investigation of recombination current versus perimeter/area ratio dependence. It was found that no pronounced difference in the recombination current parameters for diodes with different perimeter/area ratio was observed, i.e. current due to surface recombination was not observed for the 4H-SiC pn structures investigated.
Authors: Marina G. Mynbaeva, Alexander A. Lebedev
Abstract: An effective low-cost technique for rapid characterization of SiC ingots at the early stage of substrate manufacturing process is proposed. The method allows for revealing simultaneously open-micropipes, polytype inclusions, low grain boundary regions, and non-uniform resistivity. The idea of the method is to subject full-size single SiC wafer cut from an ingot to anodization treatment. The porous structure formed as a result of the treatment decorates existing defect regions via the effect of non-homogeneity in the porous structure caused by the defect-related internal stress, as well as by non-uniformity in the doping level across the wafer. The method is inexpensive, not time consuming and not fully destructive. It can also be combined with the standard selective KOH-etching technique.
Authors: Anatoly M. Strel'chuk, Viktor V. Zelenin, Alexei N. Kuznetsov, Joseph Tringe, Albert V. Davydov, Alexander A. Lebedev
Abstract: A study of forward current-voltage characteristics of Ni/4H-SiC Schottky diodes (SDs) before and after irradiation with He+ ions revealed features that characterize defect structures and reveal the degradation mechanism of the diodes. These features are the presence of excess currents of certain type in the unirradiated SDs, their appearance in forward-biased originally ideal SDs, and a >10 orders of magnitude scatter of the series resistance of the SDs upon their irradiation with He+ ions. A model of localized defect-induced current paths (shunts) in the form of unintentionally produced SDs with the substrate is suggested.
Authors: Sergey Y. Davydov, Alexander A. Lebedev
Abstract: 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.
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