Physics, Chemistry and Applications of Nanostructures

The following sections are included:

• INTERNATIONAL CONFERENCE
• FOREWORD
• CONTENTS

We have built a kinetic model of the first water monolayer growth on TiO₂(110) using the kinetic Monte Carlo (KMC) method based on the parameters describing water molecule diffusion and dissociation obtained in first principle calculations. The adsorption process has also been studied with X-ray photoelectron spectroscopy (XPS). The experiment shows that the ratio between intact and dissociated molecules monitored during the growth crucially depends on temperature with more molecules staying intact at lower temperatures. Most profound composition differences are observed at low coverage (up to 0.2-0.25 ML). Our simulations reproduce the experimental trends and rationalize these observations.

In self-assembled nanoscale porphyrin triads based on Zn-octaethylporphyrin chemical dimer (donor, D) and dipyridyl substituted porphyrin free base (acceptor, A), fluorescence quenching of D (down to 1.7-10 ps) and A (by ~1.3-1.6 times) subunits is strongly dependent on the solvent polarity (toluene-acetone mixtures) and temperature (77-350 K). The obtained experimental findings are analyzed using the reduced density matrix formalism in the frame of Haken-Strobl-Reineker approach taking into account the energy transfer, charge separation, and the dephasing of coherence between the excited electronic states of the triad.

We present our recent results on development and characterization of hollow poly(methyl methacrylate) (PMMA) microspheres loaded with CdSe/CdS core-shell quantum dots. The PMMA microspheres were fabricated using the spray-drying method and investigated using scanning electron microscopy, confocal microscopy, and fluorescent lifetime imaging microscopy. Micro-photoluminescence studies of individual microsperes were also performed revealing pronounced whispering gallery modes (WGM). The results demonstrate high optical quality of the hollow microspheres and their potential application as optical microresonators.

The oscillatory motion of electrons in a periodic potential under a constant applied electric field, Bloch oscillations (BO), predicted long ago. Oscillating electrons emit electromagnetic radiation. To date, it has been assumed that BO is a harmonic oscillation, therefore with radiation emitted at the sole Bloch frequency. We show that BO can be accompanied by the emission of radiation with multiple frequencies.

We report on a density functional theory (DFT) simulation of hyperfine interactions (hfi) in the H-terminated cluster C₅₁₀[NV]⁻H₂₅₂ hosting an NV center and present for the first time calculated hfi matrices for eight specific positions of ¹³C nuclear spins disposed on the NV center symmetry axis.

The problem of nature and thermal stability of the bond between nanodiamond core and perfluorobuthyl radical is addressed with the aid of near edge X-ray absorption fine structure spectroscopy and quantum chemistry calculations.

Molecular dynamics technique has been applied to simulate the flat C₆₀ islands having a fullerite-like structure. Simulations reproduce well the main experimental results of the scanning tunneling microscopy study of C₆₀ island growth on In-adsorbed and Tl-adsorbed -Au surfaces. C₆₀ arrays have different asimuthal orientations, developing the moiré patterns in the islands and difference in the magic C₆₀ island shape on different substrates.

Magnetic moments of the carbododecahedron (C₂₀ fullerene) with charges from (−5) to (+4) (in units of the elementary charge e) were calculated by linear combination of atomic orbitals method at the density functional level. It is established that the C₂₀ in the charge state (−1) and the multiplicity 2 has the lowest total energy, while for charge states (−4), (−2) and (+4) the magnetic moment of μ = 2μ_B (μ_B is the Bohr magneton) is found. Depending on the charge state and the multiplicity, carbon bonds and the I_h symmetry of the starting structure of the C₂₀ can change substantially. Neutral C₂₀ may have μ = 2μ_B.

Crystal lattice parameters, electronic band structure and density of states of 2D thin films of tin sulfide were investigated by means of ab initio simulation. Two orthorhombic phases (low-temperature α-SnS and high-temperature Α-SnS) and three surfaces (100), (010) and (001) were considered. All compounds were found to be semiconductors with the band gaps which are decreasing upon increasing of the film thickness approaching to the ones of the bulk materials.

Simulation of optical transmission and reflection spectra of porous anodic aluminum structures were performed, including comparison of results by the finite differences time domain method and the transfer matrix method. A procedure of effective dielectric permittivity retrieval was based on the modified Maxwell-Garnett formula. Presented results show the limits of applicability of dielectric permittivity averaging theory for anodized oxide aluminum with pores filled by silver and without filling.

The concept is proposed of extreme loss-anisotropy in fishnet metamaterals, where the longitudinal component of the permittivity tensor has ultra-large imaginary part. It is shown that changing the geometrical parameters of this structure one can realize different regimes of functioning, for example, diffraction-free lossless beam propagation and omnidirectional reflection.

Layers of silicon nanowires (SiNWs) formed by metal-assisted chemical etching of low boron doped monocrystalline silicon (c-Si) substrates were investigated by means of the optical spectroscopy of reflection/absorption in visible and near-infrared regions. The total reflection of SiNW layers with thickness above 1 μm was significantly lower than that of c-Si wafer for the spectral region above the band gap of c-Si, while it was comparable or even higher than the c-Si reflection in the near-infrared range below the band gap. An approximation of the diffusive propagation of light was found to be applicable to explain the near-infrared spectra of SiNWs.

We demonstrate a very simple method of carbon incorporation in silica nanopowder using sucrose as a carbon precursor. Dehydration of sucrose adsorbed in fumed silica host resulted in formation highly luminescent SiO₂:C nanocomposite. Effects of chemical and thermal dehydration of sucrose molecules as well as carbon content on spectral properties of broad band photoluminescence (PL) and PL relaxation properties were studied. It is shown that carbon incorporation plays a crucial role in formation of light emitting centers but thermal stimulation is not necessary for those centers emitting in near ultraviolet-violet-blue spectral range while formation of green-orange emission centers needs thermally activated reconstruction in the material. Mechanism of white PL in SiO₂:C nanocomposites is discussed in terms of carbon related point defects and carbon nanoclsuters.

Terbium photoluminescence (PL) from strontium titanate (SrTiO₃) xerogels was investigated. The xerogels were fabricated on monocrystalline silicon, porous anodic alumina grown on silicon and membranes of porous anodic alumina (PAA). Room temperature terbium PL was observed for the strontium titanate xerogel/PAA structures after annealing at 750-800 °C whereas no terbium PL has been revealed for the same xerogels fabricated on monocrystalline silicon.

Colloidal quantum-sized CdSe nanoplatelets were synthesized. Photoluminescence (PL) spectra of nanoplatelets placed in the external electric field and excited with various radiation sources were measured. The functional dependence of PL intensity vs magnitude of the electric field is in good accordance with the E^−1/2 law. This dependence is similar to that for CdSe nanorods contrary to the E⁻² law for CdSe quantum dots.

Large-scale fabrication of nano-sized sources is one of the major challenges facing nanophotonics with regards to the production of on-chip all-optical devices. During the past decade, plasmonics has demonstrated the potential to confine and process optical signals on nano-scale dimensions. However, so far, plasmonics has had limited success in the development of nano-scale sources due to the limitations imposed by the properties of active (fluorescent) materials. Here, we discuss these limitations and explore the implications they have with respect to the selection of the geometry of the plasmonic system. In particular, we show that several properties of plasmonic ring cavities are beneficial in this regard, and that they can be used to controllably alter the collective radiative behavior of semiconductor quantum dots placed selectively in their vicinity.

We present our recent results on development and characterization of three-component hybrid sytems consisting of plasmonic nanostructures and two different organic dye molecules in a J-aggregate state. The measured absorption spectra exhibit strongly suppressed absorption at wavelengths which correspond to the J-aggregate absorption bands, manifesting strong interaction between the localized surface plasmon of the plasmonic and excitonic systems. The observed dips in the absorption spectra of hybrid systems correspond to an average vacuum Rabi splitting of the order of 200 meV.

It is well known fact that either fluorescence enhancement or fluorescence quenching for the molecules near the surface of plasmonic substrate may be achieved by the varying the distance between the molecule and the substrate. We show the first experimental measurement demonstrating the transition from fluorescence enhancement to fluorescence quenching due to spectral detuning in the core/shell CdSe/ZnS nanocrystalls (NCs) deposited directly on the surface of plasmonic gold film (PGF). Strong resonant fluorescence enhancement needs to minimize the spectral shift between the position of localized surface plasmon (LSP) band maximum and first ecxitonic peak in NCs absorbtion spectrum.

Effects of the UV irradiation on optical properties of hydrogenated diamond like carbon (DLC) nanocomposite films containing Ag nanoparticles (DLC:Ag) deposited by direct current (DC) unbalanced reactive magnetron sputtering were studied in 180-1100 nm range. Additional annealing experiments were conducted. It was determined that both heating and UV irradiation affected transmittance and reflectance spectra of DLC:Ag films. However since these cause opposing effects, there is a competition between the heating and UV activated Ag nanoparticle charge processes.

Optical properties of hybrid nanostructured systems “metal nanoparticle-photochromic molecule” were studied using scanning near-field optical microscopy (SNOM). The reversibility of photochromic reactions was demonstrated. From the result obtained it may be inferred that SNOM is a useful tool in studying the local switching of photochromic molecules, and it has much potential for nanomachining of nanoscale structures and optical elements.

We present simulation results for growth dynamics of a conductive filament in oxide nanostructures. Switching threshold voltage and resistance of a resistive memory cell and its dependence on sweep rate and operating temperature, as well as the dynamics of electronic switching of bi-stable centers in metal nanooxide-based resistive random access memory (RRAM) are analyzed.

The effect of proton and neon ion irradiation on the parameters of bipolar resistive switching in SiO_x-based memristor structures fabricated by magnetron sputtering technique on TiN/Ti metalized SiO₂/Si substrates has been studied. It is shown that the high-resistance memristor state has high tolerance to the radiation exposure, whereas the low-resistance state is found to be sensitive to both ionizing and defect-producing ion irradiation.

Surface conductivity study of Si(111) reconstructions: are presented and discussed. The evolutions of electrical conductivity for these reconstructions after adsorption of atoms (alkali metals, In, Sn and others) in combination with low energy electron diffraction (LEED), scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES) observations were studied. It was established that changes in the atomic structure cause modification of its electronic band structure as revealed by ARPES measurements and well correlated with surface conductivity variations.

An effect of adsorbed oxygen on the conductivity of fluorinated copper phthalocyanine films (CuPcF) fabricated by thermal deposition in vacuum was studied by the cyclic thermodesorption method. The results are explained in terms of the hopping conductivity model. The cyclic thermodesorption method in combination with the hopping conductivity model can be used in determination of the type of centers (intrinsic versus impurity) involved in the hopping transport.

The magnetization oscillations excited by an electric current due to the spin transfer torque in a ferromagnetic/diamagnetic metal/ferromagnetic multilayered nanostructure, in which the pinned ferromagnetic layer (spin polarizer) has an in-plane magnetization direction, were theoretically studied. In this structure, the magnetization oscillations can be generated without external magnetic fields if the easy-axis of the free ferromagnetic layer is perpendicular to the magnetization of the pinned layer. The frequency dependence of these oscillations on the current density and the magnetic damping parameter, as well as the dependence of the threshold current density on the demagnetizing factor has been investigated.

We have used molecular dynamics simulation to study the possibility of using carbon nanotube bundles for helium storage. Adsorption of helium on homogeneous and heterogeneous bundles of carbon nanotubes has been studied. The adsorption coverages were calculated. This quantity indicates that carbon nanotube bundles are proper nanomaterials for gas storage.

To determine the proximity of thermoelectric materials (TM) to a phase of “phonon glass - electron crystal” (PGEC) we have developed the method of λ-diagnostics. The method is based on comparison of the mean free path of electrons λ_e and phonons λ_ph in TEM and followed by determination of the status sample relative to the PGEC phase (1= λ_ph/a<<λ_e/a, here a ~ 0.3 nm is the interatomic distance). Thus, as a result, we have defined the upper limits to improve Z of TM using nanotechnology techniques.

The structure of water incorporated into porous fiber matrixes and their microwave characteristics are investigated. Microwave characteristics of porous matrixes filled with water demonstrate the presence of nanosized forms of water. The contribution of these forms of water in dielectric characteristics of the water-containing matrix is significant for porous materials with a large surface area.

Submicron Ni rods arrays have been investigated using photoemission electron microscopy with high intensity synchrotron radiation for the first time. It is shown that Ni rods are connecting with bridges and formed by a metallic nickel which is stable to ambient oxidation. No formation of intermediate compound phases (silicides and oxides) is observed at the Ni/SiO₂ heterojunction, whereas oxidized nickel species are identified on the surface of the surrounding matrix.

Raman spectroscopy was used to identify conditions of a bent carbon nanotube. We demonstrated that G mode shifts downwards upon nanotube bending. This frequency shift is attributed to the tensile stress.

Electronic structure and phase composition of SiO_x/Si amorphous films fabricated using dc-plasma are presented. The presence of amorphous silicon phase and silicon oxides of different stoichiometry are revealed.

Al–Si nanocomposites have been produced by magnetron sputtering of a compound target onto a silicon substrate. Nanostructured silicon films have further been obtained by selective removal of aluminum. It has been found that silicon particles are nanocrystals with the mean size of 20-25 nm, which surface is covered by an amorphous layer with a thickness of ~5 nm. The band structure (in particular, near the bottom of the valence band) of the nanocomposite films was found to differ from the bulk material because of an influence of the aluminum matrix. After the aluminum removal, the valence band structure becomes identical to that in the bulk material.

Optical and electrical properties of Mg stannide and germanide nanolayers grown by solid phase epitaxy on a Si(111)7×7 substrate have been studied. It was shown that all grown ultrathin (45-90 nm) films are semiconductors with small band gaps: 0.17-0.22 eV for Mg₂Sn and Mg₂Sn_xSi_1-x, 0.70 eV for Mg₂Ge and 0.56 eV for Mg₂Ge_xSi_1-x. Optical functions, interband transitions and mechanism of electrical transport of carriers in all films have been determined.

For the first time CoPd antidot arrays are fabricated by deposition of CoPd multilayered films on nanoporous TiO₂ grown on Si wafers. Systematic analysis of magnetization curves M(H) evidences conservation of perpendicular magnetic anisotropy and enhancement of coercive field H_C associated with pinning of magnetic moments on nanopores. Magnetic characteristics of films are discussed with respect to the influence of flattened surface of TiO₂ template on local misalignment of magnetic moments in the films.

The paper is focused on the results of local structure analysis and magnetometry of granular nanocomposite films FeCoZr–CaF₂ irradiated with Xe ions at different fluences. The observed effect of enhanced perpendicular magnetic anisotropy characterizing initial films is discussed with respect to the irradiation regimes.

Results of scanning tunneling spectroscopy on atomically clean surface of topological insulator Bi₂Se₃ crystals are presented. The Seebeck coefficient of the studied crystals corresponds to p-type conductivity. The scanning tunneling spectroscopy reveals that the chemical potential is positioned inside the bulk band gap within 50-100 meV from the Dirac point of the topologically-protected surface states. We observe significant changes of local density of states near the quintuple layer steps. The changes correspond to shifts of both bulk and surface states near the step edge. Additional modification of the surface states cannot be excluded.

We present optical properties of CdSe/CdS/ZnS quantum dots (QDs) embedded in onedimensional photonic crystals (microcavities and Bragg reflectors) based on porous silicon. QD photoluminescence spectra and angular distributions have been measured. A drastic narrowing of QD photoluminescence spectrum at the microcavity eigenmode wavelength has been observed after embedding and angular distribution of luminescence has become unidirectional. We have compared these results with photoluminescence of QDs embedded in porous silicon Bragg reflector and QD film on silicon wafer. The obtained results show an enhancement of QD luminescence at the edge of photonic band gap and at microcavity eigenmode wavelength.

The magnetic behavior of the FeGa₂Se₄ single crystals has been investigated by magnetic and Mössbauer spectroscopy. Hyperfine parameters indicate that iron is in the Fe²⁺ oxidation state, with a minor (25%) Fe³⁺ fraction, located at different layers in the structure. Low-field magnetization curves showed that the low-temperature transition occurs at T_G=5.4 K, which has been assigned to the onset of a glassy state.

The oscillations in infrared reflectance spectra of nanoporous anodic alumina (NAA) formed in 0.3 M aqueous solution of oxalic acid were studied. The number and position of oscillation maxima in the reflectance spectra are shown to depend on both film thickness and pore size in the NAA.

Simulation results of three engineering applications of the Brownian diffusion of nanoparticles are presented. The first application is the Brownian deposition of nanoparticles on a reactor wall from a nonisothermal laminar gas flow. The second one is the interference of femtoliter droplet evaporation and Brownian diffusion of nanoparticles inside it. The surface Brownian diffusion of nanoparticles is the last case.

First-principle calculations demonstrate a possibility of band-gap engineering in two-dimensional hexagonal dichalcogenides like MoS₂, MoSe₂, WS₂, and WSe₂ by impurities and vacancies. Oxygen impurity atoms are revealed to substitute sulfur/selenium ones or adsorb on top of them. In the first case there is an increase of the band gap and transformation of MoSe₂ from indirect-gap to direct-gap semiconductor. Adsorption of oxygen atoms on the surface decreases the band gap.

The formation of bound states in Dirac materials is a highly nontrivial task due to the suppression of backscattering for chiral electrons with a Berry phase of π. Indeed, it is widely claimed confinement via purely electrostatic means is impossible. Here we provide a caveat to this belief by demonstrating theoretically that bound states can arise at the Dirac point. We also investigate the two-body problem for two electrons and discover an exotic paring can occur at zero-energy.

It is shown that two-dimensional nature of the acoustic phonons in graphene promotes the integer quantum Hall effect at room temperature. In contrast to the case of threedimensional phonons, the threshold of ħω_c is set up for the energy transfer by twodimensional electron-phonon interaction. Consequently, at sufficiently strong magnetic fields the cyclotron energy starts to play the role of effective temperature in the quantum percolation problem, which explains experimental discovery by Novoselov et al. [1].

Monolayer molybdenum disulfide (MoS₂) and diselenide (MoSe₂), as semiconductors with a direct band gap, have attracted much attention recently due to their novel properties, and potential application in field effect transistors, photo-electronics, spintronics, valleytronics. Previously, monolayer MoS₂ or MoSe₂ were exfoliated with an adhesive tape. Here, both monolayer MoS₂ and MoSe₂ are synthesized with a very simple chemical vapor deposition method. The as-grown samples are characterized with Raman and photoluminescence, demonstrating the samples are monolayer.

Gamma irradiation effect is considered in air on graphene flakes transformation into carbon nanostructures such as “domes”, “stars” and “nanorods”. Structure and composition of the structures are studied by optical, electron scanning and atomic force scanning microscopy and also by micro-Raman and Auger spectroscopy. The mechanisms of generation of the structures are discussed.

Thermodynamic stability and mechanical strength of the artificial and natural nanostructures (NS) of semiconducting and semimetallic thermoelectric materials (TM) based on layered Bi₂Te₃ crystals are considered. Natural Bi₂Te₃ NS tend to exhibit the greater stability than artificial NS of the same composition.

Optical properties of indium selenide (InSe) nanoflakes prepared by micro-mechanical cleavage are summarized and presented. First of all, the optical contrast between thin InSe flakes on SiO₂/Si substrates is used to detect and estimate the thickness of few layer InSe nanoflakes using standard white illumination and color CCD imaging. Secondly, these nanoflakes were characterized by micro-photoluminescence at low temperatures: a blue-shift up to 0.2 eV is found for the thinnest InSe nanoflake.

We have studied electronic properties of oxygen doped α-graphyne by the density functional theory (DFT). The α-graphyne sheets with 3% and 6% oxygen impurity were considered. It is found that α-graphyne is a semimetal. α-graphyne doped with oxygen is an n-type semiconductor. The energy band gap is decreased by increasing the impurity concentration. The results identify that doping is a proper way to change and control electronic properties of α-graphyne.

The electrical properties of hybrid films consisting of SWCNT and WS₂ nanotubes were studied by means of impedance spectroscopy in the frequency range of 20 Hz - 1 MHz at 4.2, 77 and 300 K in the range of applied bias voltage of 0-5 V. It was found that hybrid films exhibit strongly non-linear properties at 4.2 K. Equivalent circuit for modeling of hybrid films' impedance was proposed.

We present here our work investigating various methods to store hydrogen in WS₂, namely inorganic nanotubes and inorganic fullerene-like nanoparticles. We show that all hydrogenation methods applied in this study result in hydrogen absorption and diffusion, however, exposure of the substrate materials to plasma activated hydrogen results in substantial enhancement of the storage capability. Physical and chemical properties of absorbed hydrogen and WS₂ are investigated using a range of analytical methods.

Fundamental electromagnetic and electromechanical properties of CNTs, graphene nanoribbons (GNR) and nanofibers (GNF), CNT- and graphene-based aerogels (CNTBA, GBA), CNT- and graphene-based 3D-nanofoams and carbon-based polymer nanocomposites are essential for various nanotechnology applications, e.g. for engineering new classes of ultra-light, highly conductive nanomaterials with exceptional mechanical strength, flexibility, and elasticity. These nanomaterials are the basis for unique nanoelectronic devices and nanosensors. Particular properties of carbon-based nanoporous systems in dependence on the porosity extent, morphology and fractal dimension allow finding practically useful correlations between their mechanical and electrical properties. Electromagnetic properties of CNTs and GNRs nanostructures with functionalized atomic groups and their various interconnects with the essential concentration of ‘dangling bonds’ are very sensitive to local external perturbations. The induced changes of local electronic density of states lead to the correlated changes of current and spin states. Models of nanocarbon spintronic devices are developed as memory nanodevices, particularly, based on magneto-resistance phenomena. Models of nanocomposite carbon-based materials and nanodevices are proposed.

It is demonstrated theoretically that the strong coupling of an electron gas to photons in nanostructures with broken time-reversal symmetry suppresses the elastic scattering of electrons. As a consequence, the electron gas can flow without dissipation at low temperatures. This quantum macroscopic phenomenon is analyzed for a two-dimensional electron system in a semiconductor quantum well exposed to an in-plane magnetic field.

Dielectric/electric properties of onion-like carbon (OLC) and its composites were investigated over extended frequency (20 Hz - 3 THz) and temperature (26-500 K) ranges. The percolation threshold in these composites strongly depend on the OLC aggregate sizes being the lowest for the smallest aggregates. Moreover, these composites exhibit interesting thermal behaviour and pronounced thermal hysteresis close to the percolation threshold.

We study interaction of a sandwich structure consisting of graphene layers spatially separated by polymethylmetacrylate (PMMA) slabs with terahertz radiation (0.2-1.2 THz range). Experiments and numerical calculations demonstrate extremely high absorption, up to 30% by the single graphene layer. The strong absorption in graphene layer can be used in developing of highly sensitive detectors of THz radiation.

We report the experimental study of electromagnetic (EM) properties of fluorographene in K_a-band synthesized by gas-phase fluorination of few-layered graphene. The quality of the films was monitored by Raman spectroscopy.

We present a theoretical study of the contribution of single-walled carbon nanotubes (SWCNT) agglomerates to the electromagnetic response of SWCNT-based suspensions in the frequency range of 500 MHz – 20 GHz. Our simple theoretical estimation predicts the strong screening effects in agglomerates of SWCNT resulting in the weak response of SWCNT suspension after agglomeration.

Copper nanoparticles (NPs) have been synthesized on the surface of graphene nanoplatelets (GNP). This material has good film forming properties, the sheet resistance of about 400 Ohm/sq, and metallic type of conductivity. The addition of 0.05% of GNP and especially GNP+CuNP to a polymer results in the conductivity increase.

Results of broadband dielectric/electric investigations of epoxy resin filled with graphene nanoplatelets (GNP) are presented in the temperature range of 25-500 K. The percolation threshold in such system was established to be 2.87 wt.%. Above the percolation threshold dielectric permittivity and electrical conductivity are very high in whole frequency range. In this case electrical conductivity occurs via tunneling between GNP clusters. Potential barrier for tunneling decreases with GNP concentration.

Influence of the interface between the carbon system and ferromagnetic nanoparticles embedded into the carbon nanotubes on the interaction with the electromagnetic radiation in the frequency range of 20-200 GHz is studied numerically. Such interfaces are characterized by the presence of resonance circuits including resistive, capacitive and inductive elements. It is shown that the influence of the resonance circuits leads to the emergence of specific resonances in the frequency dependence of the reflection and transmission of electromagnetic radiation.

Using tight-binding model for π-electrons we investigated band structure of some subclasses of chevron-type GNRs. In chevron GNRs with mixed zigzag and bearded edges we found isolated degenerated flat bands, that can be modified to a quasi-linear bands by means of an external transverse electric field.

We studied the temperature dependence of the critical current density, J_c^S/I/F(T), of a Nb/SiO₂/PdNi trilayers before and after the magnetization of the PdNi layers in both out of plane and in plane directions. Nb and PdNi thin films interact via the electromagnetic coupling. We show that after the out of plane magnetization the magnitudes of critical current density become minimal far below the critical temperature T_c, while close to T_c the difference in magnitudes of J_c^S/I/F weakly depends on directions of magnetization. This effect is discussed in terms of spontaneous vortex – antivortex pairs induced in Nb thin film due to the electromagnetic coupling with the PdNi layer.

Electromagnetic response from a finite-length single-walled carbon nanotube (SWCNT) with a single narrow low-conductive defective region has been theoretically studied in sub-terahertz range. The strong dependence of the SWCNT polarizability on the defect conductivity has been shown and analyzed.

Interaction of electromagnetic fields with two types of nanoantennas including additional fullerene molecule placed in a gap between metal bodies was simulated. The first one is a dimer of nanospheres. The modeling has shown that, the significant reduction of the plasmonic resonant field enhancement takes place due to the tunneling effect. The second type of the system is a bowtie antenna with fullerene supplemented with special leads to apply the additional voltage. For this nanoantenna the highly nonlinear response has been demonstrated. The radiation scattered by this antenna has a wide frequency spectrum. The device proposed can be tuned by means of the bias voltage.

Colloidal semiconductor nanoparticles were the subject of numerous studies due to their intriguing properties that could be varied to a large extent. To date various protocols for preparation of colloidal nanostructures that allow altering their size, shape and composition were developed. In this report, we provide a review of the current success achieved in our group in the manufacturing of recently introduced atomically flat colloidal nanoplatelets and heteronanostructures based on A^IIB^VI semiconductors. We discuss in brief their optoelectronic properties and provide some insights on their future implementation for practical applications.

Metal oxides as a rule oxidize and oxygenate substrates via the Mars-van Krevelen mechanism. A well-defined α-Keggin polyoxometalate, H₅PV₂M_O10O₄₀, can be viewed as a nanoparticle analog that reacts via the Mars-van Krevelen mechanism both in solution and the gas phase. Guided by previous experimental observations we have studied the mechanism of its reduction by various compounds, using high-level DFT calculations. These redox reactions of polyoxometalates require protons and thus such complexes were explicitly considered. First, the energetics of outer-sphere proton and electron transfer as well as coupled proton and electron transfer were calculated for various substrates in a gas phase and in a solution. This was followed by identification of possible key intermediates on the subsequent reaction pathways that feature displacement of the metal atom from the Keggin structure and coordinatively unsaturated sites on the H₅PV₂M_O10O₄₀ surface. Subsequent coordination allows formation of reactive ensembles on the catalyst surface for which the selective oxygen transfer step becomes feasible. Calculated geometries and energies of metal defect structures support experimentally observed intermediates and demonstrate the complex nature of the Mars-van Krevelen mechanism.

Small clusters of the As/Sb-S/Se system that is of importance for simulation of elementary structure units of chalcogenide glasses are calculated using DFT technique. Different structures of As₂X_n- and Sb₂X_n- (X=S, Se) with proper hydrogen termination are compared by the total electronic energy. As₂X₃ (i.e. two face-shared pyramids of C_3h symmetry) are the most stable versions, while Sb₂Se₃ is distorted from a compact form.

A novel synthetic strategy for morphology-controllable growing of hexagonal M_oO₃ particles in aqueous medium employing polymolybdic acid as a precursor has been proposed. Both nanosized particles of spherical shape and rod-like micron-sized crystallites can be obtained by changing the synthetic conditions during the course of growing of oxide particles.

We describe the electrochemical deposition of ZnO from the nonaqueous dimethylsulfoxide ZnCl₂ solution into the porous silicon (PS) template. Formation of PS was carried out by anodization in a pulsed galvanostatic mode, which allows to obtain more regular porous structure. The correlations between the parameters of ZnO electrochemical deposition and pore filling process were studied as well.

An immersion deposition of copper on porous silicon (PS) from an aqueous solution of the copper sulfate and hydrofluoric acid has been performed. The PS based on n⁺ – and p⁺ – silicon (Si) wafers has been used to study the Cu deposition depending on the conductivity type of the initial Si substrate. The PS/n⁺-Si substrate has been found to allow the deposition of the nanostructured Cu films on the PS, while the PS/n⁺-Si has been shown to provide formation of porous Cu films by the complete substitution of Si atoms in the PS with Cu atoms.

Conditions for silver nanoparticles fabrication in aqueous solution in the presence of DTPA and NTA complexones without reducing and polymeric stabilizers by optical spectroscopy and TEM were studied. It was found that DTPA silver sols are more efficient for Raman Scattering enhancement.

Gadolinium silicide (Gd₅Si₄) and alloyed Ag-Au nanoparticles were synthesized by laser irradiation of the mixture of colloidal solutions containing nanoparticles of relevant elements. It is supposed that the compound nanoparticles are formed through nanoparticles heating, co-melting, atom interdiffusion and chemical reactions in liquid droplets.

A study of titania nanotubular (TNT) layers growth kinetics in the viscous fluorine-containing electrolyte based on ethylene glycol, using rotating disk electrode (RDE) technique is presented. RDE rotation speed at initial stages of titania growth influences metal oxidation and oxide dissociation.

CNTs grown by aerosol CVD have been studied by analytical transmission electron microscopy to determine their structure and distribution of Fe catalyst. The CNTs have am ultiwall structure and diameters in the range of 11-85 nm. Fe is found to locate at the NT tip as well as along the CNTs.

Underpotential deposition (UPD) of metals on tellurium is the basic process in the electrochemical assembly of telluride nanostructures. Unlike UPD of a metal on a foreign metal substrate characterized by the underpotential shift ΔE_UPD correlated with differences of work functions of the both metals, the UPD of metals on tellurium shows ΔE_UPD not correlated with work functions of the deposited metal and tellurium. We have investigated the underpotential shifts of Pb, Cd, Zn, Bi, In, Sn and Cu on Te and shown the correlation of ΔE_UPD with the free energy of the bulk metal telluride formation.

FeCo nanoparticles with calculated mass content Fe₅₀Co₅₀, Fe₂₅Co₇₅ and Fe₇₅Co₂₅ were obtained in water solution in a simple chemical synthesis. According to the XRD analysis all samples contain FeCo alloy and the products of the oxidation of metals (FeO(OH), CoFe₂O₄, FeO). TEM investigations show that samples have bimodal distributions of the particle size.

Tribological properties of multilayers of triacontanoic acid (TA) formed on silicon surfaces by the Langmuir-Blodgett (LB) technology were studied by a ball-on-disc microtribometer. TA multilayers possessed the highest endurance against mechanical influence of 5 mm diameter steel ball-indenter at radius of the wear track of 2.27 mm, normal load of 1N and rotation velocity of the silicon plate modified by TA film of 10 rpm.

We present the incorporation of core-shell mesoporous silica nanospheres (mSiO₂) modified with titanium dioxide (mSiO₂/TiO₂) into the cement matrix in order to overcome the key obstacles (high water demand and decrease of consistency) which are associated with the application of nanomaterials in cementitious composites. Study has shown that presented nanostructure insignificantly affected the rheological properties of cement mortar (while compared to the popular and commercially available titanium dioxide – Aeroxide® P25) and can be successfully applied in order to obtain self-cleaning cement mortars.

Structural features, surface state and gas-sensing properties of nanocrystalline SnO₂ obtained by hydrolysis from SnSO₄ have been studied. It was revealed that a preoxidation of SnSO₄ with concentrated H₂SO₄ before the hydrolysis results in the decrease of the oxide particles size from d_aver=20 nm down to d_aver=5.5 nm and the increase in sensitivity of the thick-film SnO₂ sensors to reducing gases (CO, CH₄).

We present a short review on structure and optical properties of diamond-like carbon based silver nanocomposites deposited by reactive magnetron sputtering of silver and novel applications of this nanocomposite material. It is shown that when silver atomic concentration in the film exceeds several atomic percents, silver containing diamond-like films grow in the form of the silver nanoclusters embedded in the diamond-like carbon matrix due to segregation of silver. Plasmonic properties of thin films composed of silver nanoparticles embedded in a diamond-like carbon matrix are discussed.

Graphene is a unique high surface area support for metallic and bimetallic nanoparticle catalysts for a variety of important chemical transformations. Structural defects in the graphene lattice can be useful in anchoring the metal nanoparticles to the graphene surface thus achieving new surface functionalities with a tunable metal-support interaction. High catalytic activity for carbon-carbon cross-coupling reactions has been observed for Pd nanoparticles supported onto graphene nanosheets. A new class of highly efficient Fe-based nanocatalysts supported on graphene has been discovered for the Fischer-Tropsch Synthesis of long-chain hydrocarbons from syngas. The high activities of the graphene-supported catalysts are attributed to the defect sites created in the reduced graphene oxide which can provide optimum catalyst-support interaction.

GaAs nanostructure growth via vapor-liquid-solid mechanism was realized using lattice Monte Carlo model. Characteristics of nanostructures grown by droplet epitaxy technique and self-catalyzed nanowires were analyzed. Series of nanostructures were obtained after Ga drop crystallization at different temperatures and intensity of deposited As₂ flux: compact three-dimensional crystals, core-shell nanoclusters with liquid gallium core, nanorings, and nanoholes. It was demonstrated that the formation of nanoholes and nanorings was possible only on the substrates with (001) surface orientation. Substrate etching by a gallium drop on GaAs(111)A and GaAs(111) surfaces was not observed. Self-catalyzed nanowire growth was analyzed. Dependence of nanowire morphology on the growth parameters was shown. Self-catalyzed growth was demonstrated to be very sensitive to arsenic/gallium flux ratio. There were optimal temperature and As/Ga flux ratio corresponding to enduring GaAs nanowire growth.

Physico-chemical backgrounds for the governed formation of porphyrin j-aggregates (j-AP) and porphyrin nanotubes (PNT) in solutions and on Ag colloid nanoparticles are presented. Structural and possible functional properties of these nanostructures have been characterized by means of various experimental methods (optical absorption, Raman spectroscopy, SERS and AFM).

A model for pore filling with metal-containing compounds during the electrochemical deposition is proposed and verified experimentally. It justifies a possibility to fill electrochemically nanoporous structures by two ways: either (i) the deposition onto the whole geometric surface of the porous structure or (ii) the pore filling from the pore bottoms.

The possibility of graphenelike thin films by pulsed laser ablation of graphite in air is shown. Semitransparent thin films with the thickness of 40-90 nm are analyzed using SEM, TEM, AFM, electron diffraction, Raman shift and optical spectroscopy. At the considered conditions the obtained film consists of graphenelike particles and polycrystalline inclusions.

Antidot arrays of FePd L1₀ alloy with high out-of-plane magnetization component have been fabricated by deposition of Fe/Pd multilayers on the anodic aluminum oxide templates and their successive annealing at temperatures 450 °C and 530 °C. X-ray diffractometry proved formation of L1₀ structure after sample annealing at 530 °C. Magnetometry, magnetic force microscopy and scanning electron microscopy reveal that the enhancement of out-of-plane magnetization component is associated with complex distribution of magnetic moments orientation in FePd films deposited on the templates with a developed surface topography.

Porous aluminium anodization has been carried out at anodic voltages varying from 20 to 180 V in sulfuric acid electrolytes. Very high anodic voltages at room temperature have been achieved leading to new parameters of porous alumina such as interpore distance up to 300 nm, forming cell factor up to 1.3 nm/V, volume expansion factor up to 3.5, porosity up to 1 %, sulfur concentration up to 7.7 at.%.

A central angle of porous alumina cells has been measured for anodic films formed in 6.3 M H₂SO₄ electrolyte at anodic voltages in the range of 20-180 V. The measurements have shown that central angles can reach 90 deg at anodic voltages larger than 100 V. The electric field distribution in porous alumina cells has been simulated for different central angles. It allows to propose the existence of nanoplasma regions near the pore bottom and near aluminium peaks.

Thin film SrTiO₃ capacitors were fabricated on silicon using the sol-gel method. The dependence of capacitance on voltage was observed at the room-temperature and frequency of 1 MHz. Tunable dielectric properties of the thin films are discussed.

The simple and effective method of formation of porous silicon (PS) and other PS structures (silicon nanowires, silicon nanobelts) by a two-step metal-assisted chemical etching was described. The basic mechanism of metal-assisted chemical etching and the effect of immersion and etching time were studied. The influence of hydrofluoric acid (HF) concentration on silver film morphology was shown. The role of noble metal in formation of PS structures was defined and described.

Correlations between structural properties of ZnO nanostructures and parameters of its hydrothermal deposition (temperature, process duration) were studied. Optimal conditions of zinc oxide nanostructures arrays deposition for random lasers applications have been determined.

Nanostructured bismuth strontium tantalate xerogels were synthesized using the sol-gel method. Xerogel was deposited by a spin-on technique on monocrystalline silicon and porous anodic alumina generated on monocrystalline silicon substrate. The morphologies and phase compositions of the fabricated structures were investigated.

Photocatalytic activity of the xerogel/porous anodic alumina in the degradation of Rhodamine C aqueous solution has been investigated. Strong photodegradation of the solution was observed on porous anodic alumina coatings modified by etched grooves fulfilled with titanium dioxide or strontium titanate xerogel.

Nanostructured titania films have been fabricated with different morphology: tubular structure with flat surface, tubular structure with cone-like tips and pillar structure. The best antireflective properties are demonstrated by tubular titania with flat surface.

Porous silicon (PS)/Fe nanocomposites were fabricated by electrochemical deposition of Fe into pores of mesoporous silicon template under the stationary galvanostatic regime. Magnetic properties of PS/Fe nanocomposite were investigated by measuring the temperature dependence (77–700 K) of the specific magnetization σ. The obtained σ(T) dependencies allowed us to determine the Curie temperature, T_C, which is very close to of the Curie temperature of the bulk Fe. A crystalline structure of the PS/Fe nanocomposites was studied by XRD. No peaks corresponded to Fe oxides are revealed on the XRD patterns.

We describe a new approach to the nanostructure array fabrication on the surface of copper indium gallium selenide films using argon inductively coupled plasma sputtering technique. For the polycrystalline films grown on glass substrates using selenization process we perform surface modification via plasma sputtering, which results in a crystallite smoothing and a formation of nanostructures with varied morphological parameters.

Ion-beam synthesis of Ge nanocrystals in thin SiO₂ films was investigated under conditions of high-pressure annealing. It was found that the pressure of about 10⁴ bar prevents segregation of Ge atoms at Si/SiO₂ interface and stimulates formation of nanocrystals within the ion-implanted region.

New experiments on the formation of porous silicon (PSi) layers with Ag nanoparticles by low-energy high-dose Ag-ion implantation are presented and a comparison of morphology and electron backscattering diffraction pattern of PSi formed by implantation and thermal annealing are considered. Metal-ion implantation is suggested to be effective technique for a formation of porous semiconductor layers with metal nanoparticles.

The method we present enables the simultaneous sharpening of silicon cantilevers tips placed on 200-mm diameter Si substrates.

The influence of thermal annealing on the delta-doped (Mn, C) heteronanostructures GaAsSb/GaAs with a low-temperature GaAs cap-layer was studied. Increase of the thermal stability of emissive properties was observed due to effect of the impurity in the delta-layer on the diffusion of point defects.

Ge and SiGe layers deposited on Si are unstable due to their lattice strain. At high temperatures they undergo dewetting, leading to their segregation into the structures with different surface morphologies. The process depends on the crystallographic Si substrate orientation, chemical composition, and thickness of deposited layers. We study the surface morphologies using scanning tunneling microscopy (STM) and scanning electron microscopy (SEM).

Polymer planar nanofluidic chip has shown its great potential in biological and chemical applications. However, the present bonding methods for planar nanofluidic chips suffer from high dimension loss and low bonding strength. In this work, a new bonding technique based on O₂ plasma and ethanol treatment was developed. By using O₂ plasma and ethanol, the PMMA planar nanofluidic chip with low dimension loss and high bonding strength can be bonded at low bonding conditions, temperature of 80 °C, force of 10 Kgf and time of 15 min.

Nanoparticles of NiAl_xFe_2-xO₄ (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) were synthesized by sol-gel method with participation of auto–combustion. X–ray diffraction patterns confirm the single phase spinel structure in the samples. The scanning electron microscope images indicated that the particle size lies in the nanometer regime. The lattice constants and X-ray density of ferrites with Al content x were determined. Nitrogen sorption analysis showed that the samples contain pores of 2-5 nm.

The experimental setup utilizing a DC magnetron sputtering source for production of metal clusters, their size (mass) selection and following deposition in high vacuum is described. The source is capable to form clusters of various metals, for example, copper, silver, gold, etc. Cluster size selection is achieved using an electrostatic quadrupole mass selector. The deposited silver clusters are studied using atomic force microscopy. The height distributions show typical relative standard size deviation of 9-13% for given sizes in the range of 5-23 nm. Thus, the apparatus demonstrates good capability in formation of supported size-selected metal nanoparticles with controllable coverage for various practical applications.

The heat resistance study of anodic alumina layers made by the open circuit potential measurements and electron microscopy is presented. The crack growth resistance of the anodic alumina layers depending on the initial aluminum alloy composition and the anodization regimes are discussed.

Transparent glass-ceramics containing γ-Ga₂O₃:Co²⁺ nanocrystals are synthesized in the lithium gallium silicate system. The observed red-shift of the absorption band related to the ⁴A_2g(⁴F)→⁴T_1g(⁴F) transition of Co²⁺ ions in tetrahedral sites and absorption saturation properties indicate that the glass-ceramics is suitable for the Q-switching of 1.5-1.7 μm eye-safe erbium lasers. Passively Q-switched Er,Yb:glass diode-pumped laser delivering 1.75 mJ of 25 ns-long pulses at 1540 nm is realized.

ZnO/Ag nanocomposites were prepared using atmospheric-pressure microplasma between electrolyte solution anode and metal cathode. An effect of Ag on the microstructure and optical properties of ZnO has been studied.

Oxyfluoride glass-ceramics containing nanosized (5-8 nm) PbF₂ crystals is synthesized in the glass system SiO₂–PbO–PbF₂–CdF₂. It is triply-doped with Yb³⁺, Eu³⁺ and RE³⁺ rare-earth ions (where RE ≣ Er, Tm or Ho). Under the excitation at 960 nm by a commercial diode, visible multi-color (orange-red, yellow, green or blue) up-conversion emission is observed. A color tuning is available due to sensitivity of emission spectrum to the heat-treatment regime. Studied materials are promising as glass-ceramic phosphors.

Two ways of using plasmon Au-films for inorganic art pigments study have been compared. Theoretical calculations of the enhancement factor (EF) dependence on the distance between point-like probe and gold nanoparticles have been performed. The average local EFs in our experiments were estimated to be 10⁴-10⁶. The dripping Au-sol on the pigments represents itself more easy and rapid way of sample preparation while using Au-films immobilized on the glass surface as a SERS-active substrate provides more efficient luminescence quenching.

Nanostructuring silicon via mesoporosity can both tune its properties and give rise to unexpected behavior. The size-dependent visible photoluminescence (PL) of silicon nanocrystals has received the most intensive study over the last 25 years. Improvements in nanocrystal size control and surface passivation have led to tunable output across the entire visible range and multiple reports of PL efficiencies that now exceed 50%. The medical biodegradability and bioactivity of mesoporous silicon, discovered in 1995, promoted its consideration as a new biomaterial and has led to clinical evaluation for cancer therapy. The optical, thermal and mechanical properties can also be remarkably different to those of macroscale silicon and have shown potential in, for example, sensing, thermoelectrics and lithium battery technology. Attention here is given to the potential of natural resources to create biogenic “green” semiconducting silicon for emerging applications of nanoscale silicon that require higher volumes at moderate cost.

This paper presents the key results obtained by the Laboratory of Nano-Bioengineering, which was founded in the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) in November 2011 in the framework of the program for attraction of world leading scientists to Russian institutions of higher education with the goal to develop a new generation of nano-bio hybrid materials with energy transfer properties, investigate fundamental physical effects occurring at the nano-bio interfaces in these materials, and demonstrate their applications to biomedicine, biophotonics and bio-photovoltaics.

We demonstrate the coating method to obtain colloidal QDs with positive charged groups on the surface which are capable to label different types of cells.

The main challenge in the area of artificial single nanopores consists of mimicking biological channels. In this context, the recent demonstration of the feasibility of hybrid biological/artificial solid-state nanopores by direct insertion of biological channels is likely the most original and promising way. Here we have tailored nanopore to insert simple ionic channel (gA) and complex biological channel (α-hemolysin).

We investigate the influence of nanopore surface state on poly-cytosine translocation. To do it, two kinds of nanopores with low aspect ratio (diameter ~3-5 nm, length 30 nm) were tailored: the first one with negative charge surface and the second one uncharged. It was shown that the velocity and the energy barrier strongly depend on the nanopore surface. Typically if the nanopore and polyC exhibit a similar charge, the macromolecule velocity increases and its global energy barrier of entrance in the NP decreases, as opposed to the non-charged nanopore.

We demonstrate here the one-photon- and two-photon-induced Förster resonance energy transfer (FRET) from CdSe/ZnS quantum dots (QDs) to bacteriorhodopsin (bR) in QD-bR hybrid material. The two-photon absorption cross section of QDs was about two orders of magnitude larger than that of bR. Therefore, the highly selective two-photon excitation of QDs in QD-bR complexes is possible. The efficiency of FRET from QDs to bR is sufficient to initiate bR photoconversion through selective two-photon excitation of QDs.

The DFT simulation is reported for the electronic structure and composition of endohedral fullerene clusters M@C₆₀-O-C₆₀@Hal as precursors for development of radionuclide nanosized agents for cancer therapy.

Porous silicon nanoparticles are promising for the development of innovative methods of cancer therapy due to their proven properties of biocompatibility and biodegradability. Nanoparticles can accumulate in tumor tissues in passive mode by being attached with receptors that are specific for certain tumors. We report aqueous suspensions of porous silicon nanoparticles as sonosensitizers of hyperthermia and cavitation effects under ultrasound radiation of therapeutic frequencies and intensities.

We developed a novel drug nanocarrier based on mesoporous silicon coated with temperature responsive polymer, which can release a drug loaded in the pores just after the critical temperature has been exceeded. The polymer coating with a modified N-isopropylacrylamide (PNIPAm) was performed by atom transfer radical polymerization after the surface modification with the reaction initiator. Silicon nanoparticles can be heated efficiently with infrared or radiofrequency electromagnetic radiation, both resulting in the collapse of polymer chains, pore openings and trigging of the drug release.

The conjugates of polyamidoamine (PAMAM) dendrimer of the 4^th generation and some substituted isothiazoles and isoxazoles were obtained, and studied in terms of possible medicinal application through analysis of their physiological influence on transverse sections (slices) of the hippocampus from male rat pups. The obtained results indicate application possibilities for dendrimeric conjugates of substituted isothiazoles and isoxazoles for control of hyperactivation of neuronal populations and tumors.

Copper nanoparticles were synthesized using sodium borohydride in one case and sodium borohydride with hydrazine hydrate in the other. XRD analysis shows the presence of cubic copper and copper (I) oxide in the samples. According to TEM, the average diameters of copper particles are 14.4, 19.9, 36.7 and 59.4 nm. It was found that particles of the smallest size are more effective against Gram-negative Escherichia coli…

Citric-stabilized colloidal solutions of Fe₃O₄ and Zn_0.18Fe_2.82O₄ nanosized oxides were studied as potential contrasting agents for magnetic resonance imaging. Zn-doped Fe₃O₄ was shown to have the higher magnetization and T₂-relaxivity as compared to pure Fe₃O₄. A low concentration threshold of the contrasting activity has been achieved for both samples.

SERS-active substrates from core/shell hydroxyapatite/silver (HA)Ag nanoparticles at the glass surface were prepared and characterized. The high level of their SERS-activity and considerable temporal stability after laser illumination was demonstrated. To our best knowledge, it is the first report on Ag-based substrates exhibiting unusual growth of the SERS signal within first 30 s after 441.6 nm laser beam exposure.

Kinetics of water-soluble silver-containing nanocomposites based on natural polysaccharide arabinogalactan was studied. The basic kinetic parameters of synthesis have been determined. The rate constants and effective activation energy of the silver nanoparticles formation in the arabinogalactan matrix have been analyzed.

We are reporting on engineering of oriented conjugates of single-domain antibodies (sdAbs) and quantum dots (QDs) for single-photon and two-photon tumor imaging. QDs with a quantum yield close to 100% where synthesized and transferred to an aqueous phase using a proprietary protocol ensuring months-long QD stability in biological fluids. The oriented sdAbs-QD nanoprobes against a panel of breast and prostate cancer biomarkers displayed excellent specificity of discrimination of tumor areas at the earliest stages of cancer development and are proved to be specific nanoprobes for detecting oncomarkers using both single-photon and multiphoton imaging.

Multilayer films on the basis of polyelectrolytes were formed by the layer-by-layer method. Their morphology was investigated by atomic force microscopy. After treatment by disinfectants (70% ethanol or 3% H₂O₂) the coating integrity was not broken, the homogeneity was preserved, and the surface roughness was ranged from 1.5 to 20 nm.

A review of recent advances in high density MIM capacitors using anodic aluminum oxide is presented. The fabrication and characterization of capacitors using barrier-type anodic aluminum oxide are presented in comparison with devices previously fabricated using porous anodic aluminum oxide. The barrier-type devices are shown to produce larger capacitance densities and better stability of operation with respect to frequency. In addition, a novel fabrication scheme for the MIM capacitors is demonstrated. This allows for the further increase of the capacitance density. It also allows the creation of nanostructured electrodes which increase the effective area of the capacitors.

Undoped BaSi₂ epitaxial films are grown on Si(111) substrates by molecular beam epitaxy. Their properties such as minority-carrier diffusion length and barrier height for minority carriers across grain boundaries are investigated. The minority-carrier diffusion length is found to be about 10 μm. This value is sufficiently large for thin-film solar cell applications. The average barrier height for holes is 30 meV. The photoresponse spectra are calculated for a BaSi₂ p⁺n abrupt homojunction diode based on the one-dimensional carrier continuity equation using previously reported experimental values. The individual contributions of the three layers, that is, the neutral p⁺-type layer, the depletion region, and the neutral n-type layer, to the total photoresponse are discussed.

It has been demonstrated that the mutual positions of the energy levels of organic semiconductors (OSs) and CdSe quantum dots (QDs), as well as their relative concentrations, are crucial for efficient photovoltaic conversion in nanohybrid structures. In particular, charge transfer in the structures based on OSs of the polyimide type and quantum dots as dependent on their concentrations was analyzed. The observed improvement of photovoltaic characteristics of the OS–QD hybrid structures with increasing CdSe QD size has been shown to result mainly from the improvement of the conditions for charge separation at the heterointerface due to an increase in the differences LUMO(OS) – Ec(QD) and HOMO(OS) – Ev(QD). The results of this study make it possible to correct the strategy of further development of hybrid solar cells based on semiconductor QDs and OSs.

Last achievements in two main applications of plasmonic metal nanoparticles for improving the efficiency of thin-film silicon solar cells are reviewed and our own results are presented. One of the applications is concerned with fabrication and investigation of diffuse rear reflectors on the basis of efficiently scattering colloidal metal nanoparticles. The second one is the use of plasmon-induced hot electrons ejected by metal nanoparticles into Si for extending Si solar cell photoresponce toward wavelengths longer than Si bandgap.

The efficiency of CdTe solar cells with the absorber layer smaller than 1 μm is analyzed. These devices are made by decreasing the CdTe thickness from the standard 6 μm down to 350 nm. The optimization steps of our low temperature fabrication process based on physical vapor deposition. Our best efficiencies are 3.4% for device with 350 nm of CdTe and 8% for device with 700 nm of CdTe.

The hydrogenated amorphous silicon (a-Si:H) based p-i-n diode structures with multiple layers (x = 8,…,15) of the embedded narrow band semiconducting silicide (Mg₂Si and Ca₂Si) nanoparticles (NPs) have been grown by combining the PECVD and RDE. Their room temperature electroluminescence has been observed in the near infrared region.

Light absorption by a monolayer and multilayer of nano- and submicron sized spherical silicon particles is theoretically investigated. The integral over the solar spectral irradiance “Global tilt” ASTM G173-03 absorption coefficient is calculated in the wavelength range of 0.28 μm≤λ≤1.12 μm. It is shown that absorption coefficient of the gradient multilayer can be much more than the one of the non-gradient multilayer.

InAs/GaSb superlattice (SL) is a peculiar quantum system for infrared detection, where electrical and optical properties are directly governed by the composition and the periodicity of the InAs/GaSb cell. Indeed, several structures with different InAs to GaSb thickness ratios in each SL period, can target the same cut-off wavelength. Likewise, the type of conductivity of the non-intentionally doped SL structure is also linked to the InAs/GaSb SL period. The objective of this communication is to use the flexibility properties of InAs/GaSb SL nanostructures to design and then to fabricate by MBE a pn photodiode structure where the active zone is made of different SL periods.

Resistive switching (RS) in Au/ZrO₂(Y)/TiN structures fabricated by RF-magnetron sputtering is studied by means of I-V characteristics and impedance spectroscopy. The RS is dependent on the exposure of the Au electrode to the atmosphere. The impedance spectra show an area dependence of the low resistance state and further changes in the states via the RS.

Nanostructured porous silicon impregnated by solid state oxidizer has been studied in order to provide the mechanical impulse for jet-propulsion microsystems. The system with jet-propulsion movement on a silicon chip has been used for impulse measurements. The estimated impulse was in the range of 25-130 mN·s.

The effect of temperature on the dc conductivity of nanoporous zeolite is described. The resistivity decreased from 2.34×10¹⁰ to 2.17×10⁸ Ω·m when the temperature increased from 28 to 800 K which was associated with the ionic mobility. I-V characteristics obtained with different experimental methods show that new mixed transport mechanisms occur when zeolites are used as a cathode in gas discharge electronic devices.

The development of a quantum dot (QD) solid is the base for the fabrication of efficient photodetectors. In the present work we incorporate PbS QD-solid films by doctor blading deposition into a Schottky heterostructure design in order to obtain high responsivities (0.15-0.45 A/W) and detectivities (10¹²-10¹³ Jones) in the infrared region, up to 1700 nm. The electronic transport through QDs is enhanced by a solid state ligand exchange strategy with mercaptopropionic acid as short organic bidentate ligand, which simultaneously produce a passivation of surface defects at PbS QDs.

An electrochemical preparation of self-organized aluminum mesh for display applications is described. This new technology can be used for production of optically transparent electrodes for display devices without indium-tin oxide films.

Numerical calculations of the optical gain of TM and TE polarization modes in strained p-Al_xGa_1-xAs/GaAs_1-yPy/n-Al_xGa_1-xAs double heterostructures of different quantum well widths (from 40 to 200 Å) and phosphor contents (y = 0-0.20) were performed for different values of the external uniaxial compression along [110], [100] and [001] directions. The results of calculations demonstrate the possibility of the effective TM/TE tuning and switching by uniaxial compression along [100] and [110] directions in A³B⁵ zinc-blende light emitting diodes with “light hole up configuration” of quantized levels in a quantum well.

Industrial applications of STT-MRAMs basically requires CoFeB/MgO/CoFeB core junction and synthetic antiferromagnetic layer (SyAF) that consists of Co-based multilayers with high perpendicular magnetic anisotropic energy under annealing. Here, four critical challenging issues including TMR ratio, critical current, thermal stability and tunneling barriers are discussed briefly. In addition, roles of additional oxide layer insertion into the CoFeB/MgO junction and Co-based multilayers was systematically analyzed to identify a possible origin of enhanced perpendicular magnetic anisotropy (PMA) characteristics.

The design and application of nanostructured anisotropic materials, conductive and alignment coatings for displays and photonic devices are described.

Titania nanorods and nanowires were synthesized via hydrothermal reaction of amorphous TiO₂ in alkaline NaOH, followed by ionic exchange in HCl aqueous solution and dehydration at 400 °C. Although the hydrothermal treatment produces three kinds of particle morphologies depending on the reaction time (nanosheets, nanorods, and nanowires), the products exhibit the same crystal structure.

Nanostructured silicon films have been fabricated on stainless steel by magnetron sputtering of an Al+Si composite target with a subsequent selective etching off the aluminum from the deposited film. They have been used as anodes in prototype Li-ion cells and subjected to cycling lithiation at high current densities. The fabricated films demonstrate an efficient Li accumulation/release during charging/discharging cycles combined with high mechanical durability.

We report on the facile synthesis of one-dimensional hematite nanostructures with large specific surface area on fluorine-doped tin oxide/glass for water splitting cells. The obtained efficiency is among the highest reported values for hematite based photoelectrochemical cells.

Supercapacitor electrodes were produced by means of chemical vapour deposition process. Electrodes features 3D structure and consist of alternating layers of carbon nanotubes and multilayer graphene. Structure and electrophysical properties of electrodes were investigated.

We have successfully fabricated graphene oxide lines and planes using local anodic oxidation with various oxidation conditions. The atomic concentration of oxygen in the fabricated graphene oxide increases proportionally to the bias voltage.

Silver dendrites have been grown on the macroporous silicon (macroPS) by an immersion deposition. The initial stage of Ag deposition occurs according to the Volmer-Weber mechanism of the island thin film growth due to an excess of electrons of Si atoms from the rough surface of the macroPS. The next stage of the deposition is accompanied by formation of Ag dendrites because of the decreasing rate of electrons delivery from the macroPS. The resulting silvered substrates have been found to demonstrate an activity in the surface enhanced Raman scattering (SERS) at the detection of water-soluble cationic Cu(II)-tetrakis(4-N-methylpyridyl) porphyrin (CuTMpyP4).

The electrical device performance of radio frequency (RF) sputtered InGaZnO (IGZO) thin film transistors (TFTs) were improved using hydrogen ion irradiation at room temperature. The field effect mobility and subthreshold gate swing is improved with the increase of hydrogen ion irradiation dose. The electrical device performance is correlated with the electronic structure of IGZO films, such as chemical bonding states, conduction band area and band edge states below the conduction band. The decrease of oxygen deficient bonding and the changes in electronic structure of the conduction band leads to the improvement of electrical device performance in IGZO TFT with an increase of the hydrogen ion irradiation dose.

ZnO/n-CdS/p-Cu(In,Ga)Se₂ thin film solar cells with graded bandgap absorber layer have been modelled. The nanostructuring effects in solar cells formed on a substrate using porous anodic alumina was considered taking into account processes at grain boundaries and nanoordered back contact. Charge carriers accumulation at the interfaces leads to local effective bandgap narrowings at the interfaces reducing the conversion efficiency.

By using Poincaré–Bogolyubov method the nonlinear equations which describe an electromechanical vibrator based on the graphene nanoribbon are studied. A vibrator is proposed scaled to the molecular level based on the funnel-like tin phthalocyanine macromolecule. We present parameters for this device acting as a generator of electric vibrations.

We synthesized benzoxazine using bisphenol-A as a phenolic material and analyzed the structure of synthesized benzoxazine oligomers by tandem mass analysis method. The structure of benzoxazine which has bisphenol A structure as a phenolic component analyzed by tandem mass analysis. From the results, it is clear that dimethylol aniline is produced and depending on the reaction mechanism of dimethylol aniline, the final structure of oligomers are proposed.

The following sections are included:

• AUTHOR INDEX