N. L. Bazhenov

Bio: N. L. Bazhenov is an academic researcher from Russian Academy of Sciences. The author has contributed to research in topics: Photoluminescence & Molecular beam epitaxy. The author has an hindex of 8, co-authored 42 publications receiving 195 citations. Previous affiliations of N. L. Bazhenov include Tomsk State University.

Photoconductivity in porous GaN layers

Abstract: The first observation of photoconductivity (PC) in porous GaN layers fabricated by surface anodization of 0.6 μm thick GaN layers grown by HVPE on 6H-SiC substrates is reported. PC was studied at room temperature and a strong photoresponse was observed in anodized GaN layers, whereas no photoconduction in initial (not anodized) epitaxial layers was detected. Both the buildup and the decay of the PC in anodized GaN demonstrated exponential behavior with two time constants of 1.8 and 100 s, respectively. PC spectra of anodized GaN showed a steady increase of the photoresponse as the photon energy was increased from 2.5 to 3 eV. Room and low temperature (15 K) photoluminescence studies were also performed on initial and anodized structures. EBIC measurements showed formation of a barrier on the GaN/SiC interface after anodization. Photoresponse in anodized GaN layers is ascribed to a decrease in carrier concentration in the anodized semiconductor.

Photoluminescence of Hg1 − x Cd x Te based heterostructures grown by molecular-beam epitaxy

Abstract: Photoluminescence (PL) of Hg1 − x Cd x Te-based heterostructures grown by molecular-beam epitaxy (MBE) on GaAs and Si substrates has been studied. It is shown that a pronounced disruption of the long-range order in the crystal lattice is characteristic of structures of this kind. It is demonstrated that the observed disordering is mostly due to the nonequilibrium nature of MBE and can be partly eliminated by postgrowth thermal annealing. Low-temperature spectra of epitaxial layers and structures with wide potential wells are dominated by the recombination peak of an exciton localized in density-of-states tails; the energy of this peak is substantially lower than the energy gap. In quantum-well (QW) structures at low temperatures, the main PL peak is due to carrier recombination between QW levels and the energy of the emitted photon is strictly determined by the effective (with the QW levels taken into account) energy gap.

Interface-induced phenomena in type II antimonide-arsenide heterostructures

Abstract: Type II antimonide–arsenide based heterostructures have recently received great attention from researchers engaged in the design of mid-infrared optoelectronic devices. Magnetotransport properties of the semimetal channel and the interface electroluminescence were experimentally studied on type II broken-gap GaInAsSb/InAs single heterojunctions grown by LPE with high quality interface. An electron channel with high Hall mobility was, for the first time, observed at the interface of isotype p-GaInAsSb/p-InAs heterojunctions with undoped and slightly doped quaternary layers at low temperatures. A depletion of the electron channel was found to be due to the heavy acceptor doping level of the quaternary layer. The two-dimensional nature of the interface carriers was established by Shubnikov–de Haas oscillation experiments at 1.8–4.2 K under magnetic fields up to 9–14 T. Intensive interface electroluminescence in the structures under study was observed in the spectral range of 3–4 µm at low temperatures (4.2–77 K). A model of the recombination transition at the type II broken-gap interface was proposed and experimentally confirmed. A new physical approach to the design of mid-infrared tunnelling-injection lasers is demonstrated.

Optical properties of molecular beam epitaxy-grown HgCdTe structures with potential wells

Abstract: Photoconductivity and photoluminescence of HgCdTe-based nanostructures with 50 to 200 nm-wide potential wells were studied. The structures were grown by molecular beam epitaxy on GaAs substrates, and emitted light with wavelengths 2.8–3.8 μm at 300 K. The luminescence properties of the nanostructures at low temperatures were found to be strongly affected by the effect of alloy disorder, which led to a substantial red-shift of the emission spectrum in relation to energy gap of the wells. This effect could be reduced by post-growth annealing of the structures, which also increased the luminescence intensity. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Temperature dependence of the threshold current of QW lasers

Abstract: The temperature dependence of the threshold current in GaInAs-based laser structures has been studied in a wide temperature range (4.2 ≤ T ≤ 290 K). It is shown that this dependence is monotonic in the entire temperature interval studied. Theoretical expressions for the threshold carrier density are derived and it is demonstrated that this density depends on temperature linearly. It is shown that the main contribution to the threshold current comes from monomolecular (Shockley-Read) recombination at low temperatures. At T > 77 K, the threshold current is determined by radiative recombination. At higher temperatures, close to room temperature, Auger recombination also makes a contribution. The threshold current grows with temperature linearly in the case of radiative recombination and in accordance with T 3 in the case of Auger recombination.

Density-matrix theory of semiconductor lasers with relaxation broadening model - Gain and gain-suppression in semiconductor lasers

Abstract: The density-matrix theory of semiconductor lasers with relaxation broadening model is finally established by introducing theoretical dipole moment into previously developed treatments. The dipole moment is given theoretically by the k . p method and is calculated for various semiconductor materials. As a result, gain and gain-suppression for a variety of crystals covering wide wavelength region are calculated. It is found that the linear gain is larger for longer wavelength lasers and that the gain-suppression is much larger for longer wavelength lasers, which results in that single-mode operation is more stable in long-wavelength lasers than in shorter-wavelength lasers, in good agreement with the experiments.

Топонимия квебека: лингвокультурологический анализ

Abstract: 33 К наиболее эффективным и часто ис6 пользуемым методам вспомогательных репродуктивных технологий (assisted reproductive technologies) относятся: экс6 тракорпоральное оплодотворение — ЭКО (in vitro fertilization — IVF) и инъек6 ция сперматозоида в цитоплазму яйце6 клетки — ИКСИ (intracytoplasmic sperm injection — ICSI). По данным Россий6 ской Ассоциации Репродукции Челове6 ка (РАРЧ) доля ЭКО и ИКСИ в общем числе циклов ВРТ в России составляет не менее 75%. В нашей стране экстракорпоральное оплодотворение применяется с 1986 г. По данным РАРЧ, в России в 2011 г. работали более 120 клиник ВРТ, что в 4 раза боль6 ше, чем в 2000 г. По числу выполненных циклов ВРТ в 2011 г. Россия занимает тре6 тье месте в мире (после Франции и Герма6 Особенности развития детей, зачатых при помощи вспомогательных репродуктивных технологий

Interface-induced optical and transport phenomena in type II broken-gap single heterojunctions

Abstract: This review deals with a study of optical and magnetotransport phenomena at a type II arsenide–antimonide heterojunction with a broken-gap alignment. A fundamental feature of this structure is partial overlapping of the InAs conduction band with the GaSb-rich solid solution valence band. In such a heterostructure, electrons and holes are spatially separated and localized in self-consistent quantum wells formed on both sides of the heterointerface. This leads to unusual tunnelling-assisted radiative recombination transitions and novel transport properties. Results of a pioneering study of interface-related luminescence in type II broken-gap GaInAsSb/InAs heterostructures, with a high quality abrupt heteroboundary, grown by the LPE method, are presented. The energy band diagram of the type II broken-gap GaInAsSb/InAs(GaSb) heterostructures and band overlapping control, depending on a doping level and epilayer composition of quaternary solid solution, are discussed. A 2D-electron channel with high Hall mobility at the p-GaInAsSb/p-InAs interface was found and examined. A great deal of attention is paid to quantum transport properties of the semimetal channel in a wide magnetic field range (up to 18 T) at low temperatures. A cyclotron resonance study was used to obtain data on the energy spectrum at the interface and to estimate effective masses for subbands in the semimetal channel. The intriguing behaviour of the 2D-electron system in the presence of localized holes in high magnetic fields and the first observation of integer quantum Hall effect plateaus on the type II single GaInAsSb/InAs heterointerface formed by LPE are demonstrated. A tunnelling-injection laser with high asymmetric band offset confinements based on the type II broken-gap heterojunction is considered. Applications of the interface-induced phenomena in luminescent and transport properties for the design of novel mid-IR optoelectronic devices and Hall sensors are briefly reviewed.

Stimulated emission from HgCdTe quantum well heterostructures at wavelengths up to 19.5 μm

Abstract: We report on stimulated emission at wavelengths up to 19.5 μm from HgTe/HgCdTe quantum well heterostructures with wide‐gap HgCdTe dielectric waveguide, grown by molecular beam epitaxy on GaAs(013) substrates. The mitigation of Auger processes in structures under study is exemplified, and the promising routes towards the 20–50 μm wavelength range, where HgCdTe lasers may be competitive to the prominent emitters, are discussed.

HgCdTe-based heterostructures for terahertz photonics

Abstract: Due to their specific physical properties, HgCdTe-based heterostructures are expected to play an important role in terahertz photonic systems. Here, focusing on gated devices presenting inverted band ordering, we evidence an enhancement of the terahertz photoconductive response close to the charge neutrality point and at the magnetic field driven topological phase transition. We also show the ability of these heterostructures to be used as terahertz imagers. Regarding terahertz emitters, we present results on stimulated emission of HgCdTe heterostructures in their conventional semiconductor state above 30 THz, discussing the physical mechanisms involved and promising routes towards the 5–15 THz frequency domain.