R. N. Kryukov

Bio: R. N. Kryukov is an academic researcher from N. I. Lobachevsky State University of Nizhny Novgorod. The author has contributed to research in topics: Silicon & Epitaxy. The author has an hindex of 4, co-authored 11 publications receiving 84 citations.

Deep UV narrow-band photodetector based on ion beam synthesized indium oxide quantum dots in Al2O3 matrix

Abstract: Semiconductor quantum dots have attracted tremendous attention owing to their novel electrical and optical properties as a result of their size dependent quantum confinement effects. This provides the advantage of tunable wavelength detection, which is essential to realize spectrally selective photodetectors. We report on the fabrication and characterization of a high performance narrow band ultraviolet photodetector (UV-B) based on Indium oxide (In2O3) nanocrystals embedded in aluminium oxide (Al2O3) matrices. The In2O3 nanocrystals are synthesized in an Al2O3 matrix by sequential implantation of In+ and ions and post-implantation annealing. The photodetector exhibits excellent optoelectronic performances with high spectral responsivity and external quantum efficiency. The spectral response shows a band-selective nature with a full width half maximum of ~60 nm, and a responsivity reaching up to 70 A W−1 under 290 nm at 5 V bias. The corresponding rejection ratio to visible region was as high as 8400. The high performance of this photodetector makes it highly suitable for practical applications such as narrow-band spectrum-selective photodetectors. The device design based on ion-synthesized nanocrystals could provide a new approach for realizing a visible-blind photodetector.

Changes in the Architectonics and Morphometric Characteristics of Erythocytes under the Influence of Magnetite Nanoparticles

Abstract: A new high-precision technique for calculating the ratio of the erythrocyte area/volume using atomic-force microscopy has been developed. The method was tested on erythrocytes of healthy donors. Scanning electron microscopy, atomic-force microscopy, and X-ray microanalysis revealed that magnetite nanoparticles can interact with erythrocyte membranes in vitro. This interaction resulted in the development of a pathology of erythrocytes typical for poikilocytosis and anisocytosis. When the magnetite was incubated with erythrocytes in a serum-free medium, nanoparticles aggregated.

Chemical and phase composition of GaMnAs/GaAs/InGaAs spin light-emitting diodes

Abstract: The technique of X-ray photoelectron spectroscopy combined with ion profiling is used for the quantitative chemical analysis of the structure of spin light-emitting diodes with a GaMnAs spin-injection layer and an InGaAs quantum well. The depth distribution of phases is determined, and the causes of redistribution of the phases are clarified. In the spin-injection layer, the fractions of antiferromagnetic Mn and ferromagnetic MnAs are at the same level. The procedure for phase separation and verification of the correctness of determination of the content of components is improved.

Stochastic resonance in a metal-oxide memristive device

Abstract: The stochastic resonance phenomenon has been studied experimentally and theoretically for a state-of-art metal-oxide memristive device based on yttria-stabilized zirconium dioxide and tantalum pentoxide, which exhibits bipolar filamentary resistive switching of anionic type The effect of white Gaussian noise superimposed on the sub-threshold sinusoidal driving signal is analyzed through the time series statistics of the resistive switching parameters, the spectral response to a periodic perturbation and the signal-to-noise ratio at the output of the nonlinear system The stabilized resistive switching and the increased memristance response are revealed in the observed regularities at an optimal noise intensity corresponding to the stochastic resonance phenomenon and interpreted using a stochastic memristor model taking into account an external noise source added to the control voltage The obtained results clearly show that noise and fluctuations can play a constructive role in nonlinear memristive systems far from equilibrium

Noise-assisted persistence and recovery of memory state in a memristive spiking neuromorphic network

Abstract: We investigate the constructive role of an external noise signal, in the form of a low-rate Poisson sequence of pulses supplied to all inputs of a spiking neural network, consisting in maintaining for a long time or even recovering a memory trace (engram) of the image without its direct renewal (or rewriting). In particular, this unique dynamic property is demonstrated in a single-layer spiking neural network consisting of simple integrate-and-fire neurons and memristive synaptic weights. This is carried out by preserving and even fine-tuning the conductance values of memristors in terms of dynamic plasticity, specifically spike-timing-dependent plasticity-type, driven by overlapping pre- and postsynaptic voltage spikes. It has been shown that the weights can be to a certain extent unreliable, due to such characteristics as the limited retention time of resistive state or the variation of switching voltages. Such a noise-assisted persistence of memory, on one hand, could be a prototypical mechanism in a biological nervous system and, on the other hand, brings one step closer to the possibility of building reliable spiking neural networks composed of unreliable analog elements.