Physics, Chemistry and Applications of Nanostructures

The following sections are included:

• FOREWORD

• CONTENTS

Plasmonics is a field connected to optics dealing with the properties and applications of surface plasmons which are modes of metal dielectric interfaces. It has highly potential applications for ultrasensitive biochemical sensing. Surface enhanced spectroscopies are the ultimate sensor tools as they can reach single molecule sensitivity. In this paper we present our results towards the realization of highly controllable and reproducible nanoplasmonics substrates.

Phase-based quantum devices are promising for future fast and low-power consumption nanoelectronics since electron interference might be used for the switching function. A robust operation of these devices necessitates nanoscale dimensions. The epitaxial growth of III/V nanowires opens unique possibilities for the realization of low dimensional structures by employing radial and axial heterostructures within the nanowire. Here we discuss the growth of GaAs/InAs core/shell nanowires as well as their magneto-transport properties. The InAs shell forms a tube shaped electron gas with coherent circular states. Magneto transport measurements with a magnetic field parallel to the axis of the nanowire exhibit oscillations in the conductivity with a periodicity of 1/Φ with Φ being the magnetic flux. It is shown that the oscillations can be explained by the number of coherent quantum states participating in the transport.

The formalism of line groups is used to analyze the symmetry of nanowires and nanotubes based on rutile TiO₂ and perovskite BaTiO₃. The results of first-principles calculations of these nanostructures are presented and discussed. It is shown that TiO₂ based nanowires are more stable than BaTiO₃-based ones, whereas the latter are more stable than BaTiO₃- based nanotubes with the equal number of formula units per monoperiodic unit cell.

We present a theory and numerical modelling of the integer quantum Hall effect at finite temperatures considering electron-phonon interaction as a source of decoherence. Current approach is a unique tool for quantitative description of magnetotransport at low temperatures and high magnetic fields. Good agreement with the experimental data has been achieved by exploiting sophisticated numerical method of kernel polynomials.

Numerical calculations of the Fermi surface of 2D holes at p-GaAs/Al_xGa_1-xAS heterointerface found it to become strongly anisotropic under uniaxial compressions. This uniaxial stress induced anisotropy of the energy spectrum reveals in experimentally detected 2-3 times increase of 2D hole mobility anisotropy (at the uniaxial compression of about 5 kbar). It also leads to a considerable anisotropy of far-infrared absorption.

Fundamental electronic and optical properties of MoS₂, WS₂ and their based ternary compound Mo_0.5W_0.5S₂ were determined within ab initio simulations. Bulk and two-layered structures were considered. All compounds were found to be semiconductors with indirect band gaps having values increasing by reducing the number of layers.

The motion of a conduction electron in a quasi-one-dimensional wire placed into a dielectric environment with distributed inductance is considered. The possibility of the existence in the wire of an inductive soliton (or inducton) is shown and its parameters are estimated. The inducton current waveform is compressed with an increase of inductance.

Magnetotransport properties and circular polarization of photoluminescence for GaAs structures with Mn delta-doped layer and InGaAs quantum well were investigated. Manifestation of anomalous Hall effect and degree of spin polarization of carriers in the quantum well are found to depend on its depth.

Magnetic properties of Ni nanowires electrochemically deposited into pores of mesoporous silicon template under the stationary galvanostatic regime were investigated by measuring the temperature dependence (77-700 K) of the specific magnetization σ. The measured σ values were lower with respect to that of bulk Ni. The Curie temperature, T_C, derived from σ(T) for low deposition times of Ni was less (575 K) than that for bulk Ni (630 K). This is caused by dimensional effects of Ni nanoparticles.

The magnetic resonance of separate spherical nanoparticles and nanoparticle arrays is modeled by using the package Nmag. It is shown that the resonance appears in the system of interacting nanoparticles with the characteristic size of 2 nm at their concentration of 5×10¹⁸ cm⁻³.

The paper summarizes features in magnetic states of nanocomposite films like superparamagnetic relaxation, exchange interactions, enhanced magnetic anisotropy, originating from their granular nanostructure and related to various combinations of metallic (FeCo(Zr) alloy) nanoparticles and insulating (Al₂O₃, PbZrTiO₃, CaF₂) matrix as well as films deposition regimes.

Surface structure, band structure and electrical conductance of Au and Na coadsorbed Si(111)√3×√3 reconstruction have been studied in situ with low-energy electron diffraction, scanning tunneling microscopy, angle-resolved photoelectron spectroscopy and four-point probe technique. The Si(111)-h-√3×√3-(Au,Na) homogeneous structure has been detected after adsorption of 0.08-0.09 ML of sodium onto the Si(111)-α√3×√3-Au reconstructed surface at 35°C. Photoemission spectra show the details of the filling the surface state bands demonstrating the two-dimensional electron gas occurrence. Surface conductivity measurements reveal correlations with electron density changes in surface state bands and its dispersion.

Electrical properties of Te nanowires arrays were investigated in the temperature range of 2-300 K. The nanowires were fabricated by electrodeposition of Te in porous anodic alumina membrane. The crossover between metallic (dR/dT>0) and non-metallic (dR/dT<0) type of the temperature dependence of the resistance was observed at T~135 K. Metallic character of the R(T) dependences of Te nanowires is believed to be induced by unintentional doping from surface states of the wires boundaries.

The low-temperature electrical and magnetotransport characteristics of partially relaxed Si/Si_1-xGe_x heterostructures with two-dimensional electron channel (n_e ≥ 10¹² cm⁻²) in an elastically strained silicon layer of nanometer thickness have been considered. The detailed calculation of the potential and the electrons distribution in the layers of the structure was carried out to understand the observed patterns. The dependence of the tunneling transparency of the barrier between 2D and 3D transport channels from the doping level, the degree of blurring boundaries, layer thickness, degree of relaxation of elastic stresses in the layers of the structure was studied. Tunnel characteristics of the barrier between the layers were manifested by the appearance of a tunneling component in the current-voltage characteristics of real structures. Instabilities manifested during the magnetotransport measurements using both weak and strong magnetic fields are explained by the transitions of charge carriers from the two-dimensional into three-dimensional state, due to interlayer tunneling transitions of electrons.

Magnetic properties of Co/Si/Co thin-film systems prepared by DC magnetron sputtering technique were investigated. The hysteresis loops were measured employing a magneto-optical magnetometer. The saturation field of the examined trilayers was revealed to oscillate as a function of Si layer thickness. The obtained data were explained by structural features of the Co/Si/Co samples and appearance of antiferromagnetic exchange coupling between the magnetic layers through the Si spacer.

We study optical properties of a hybrid system consisting of cyanine dye J-aggregates attached to a Whispering-Gallery-Mode (WGM) microcavity. A periodic structure of narrow peaks was observed in the photoluminescence (PL) spectrum of J-aggregates, arising from the coupling between the emission of J-aggregates and WGMs of the microcavity. We demonstrate that the emission intensity can be enhanced by depositing a hybrid layer of J-aggregates and Ag nanoparticles (NPs) onto the WGM microcavity. Owing to the concerted action of WGMs and plasmonic hot spots in the Ag NPs clusters, we observe a strongly enhanced Raman signal from the J-aggregates.

Non-resonant enhanced Raman scattering of light by ZnO nanocrystals adsorbed on glass substrates coated with silver or gold colloidal nanoparticles has been investigated experimentally. Pronounced 10⁴-fold enhancement of the Raman signal has been obtained for longitudinal optical phonons line (569 cm⁻¹) on the Ag-coated substrates. This makes feasible beyond 10⁻¹⁸ mole detection of ZnO nanocrystals and can be purposefully used in analytical applications where conjugated nanocrystals serve as Raman markers. For Au-coated surfaces the enhancement is about 10² times.

We studied electro-optical effects in 2D quantum confined CdSe nanoplatelets synthesized by colloidal chemistry. They were incorporated into transparent polymeric film sandwiched between two ITO electrodes to which the electric potential has been applied. The electro-optical response in the nanoplatelets has a Stark-like character similar to observed elsewhere for CdSe quantum dots and nanorods. However, the magnitude of the Stark effect in the platelets is of the order of magnitude higher than that in quantum dots or nanorods of an equivalent diameter. The electro-optical response from the nanoplatelets is partially polarized.

Recent results on the development of active metallic nanostructures integrated with organic dye molecules in J-aggregate state are presented. Highly efficient SERS, photoluminescence enhancement and photoluminescence lifetime modification have been observed at nanowire junctions.

We have studied the formation of InSb and InAs precipitates with sizes of several nanometers in Si and SiO₂/Si by means of implantation of (Sb + In) or (As + In) ions with energies from 170 to 350 keV and fluencies from 2.8+10¹⁶ to 3.5+10¹⁶ cm⁻² at 500°C and subsequent annealing at 1050-1100 °C for 3-30 min. A broad band in the region of 1.2-1.6 μm has been registered in the low-temperature photoluminescence spectra of both (Sb + In) and (As + In) implanted and annealed silicon crystals.

A physical explanation of the directed diffraction phenomenon is presented for the special case of the electromagnetic beam propagation inside a photonic crystal slab for which the direction of propagation is independent of the angle of incidence of the beam on the slab surface. The possibility of application of this phenomenon is analyzed.

For planar nanocomposites Ag-LiF fabricated by the thermal vacuum evaporation and characterized by a high volume part of a metal phase (p = 0.6-0.8), the concentration features of the surface plasmon absorption band were analyzed. Based on the probabilistic approach to the description of a nanocomposite structure, the new combined model of the effective medium is proposed, which takes into account the matrix inversion at the metal concentration increase over p=0.5. The model describes well the experimental data.

The features of Bessel plasmons superposition generated in a metal film of a finite thickness is developed. The possibility of generating the new type of plasmon field (Bessel multiplasmon) is shown. A scheme for its experimental realization is suggested. This superposed field is promising for application as a virtual tip for near-field optical microscopy with a nanoscale resolution.

An interaction of electromagnetic waves with a planar array of dielectric spherical nanoparticles arranged into thin absorbing film is considered on the basis of statistical theory of multiple wave scattering. On the example of thin silver films with a monolayer of air nanopores we show the role of the interference of the waves scattered in an extraordinary transmission.

Spectral and kinetic features of the surface plasmon resonance (SPR) for colloids of silver nanoparticles with carboxyalkylated amines complexons are studied by means of a femtosecond pump-probe spectroscopy. In the long-wavelength wing of the plasmon resonance, the additional laser-induced bleaching band was observed. The rise time of the red bleaching band was found to be of few tens of picoseconds and its decay occurred for about 2 ns. The observed SPR changes may be attributed to the fast breaking and restoring back the nanoparticle connected with the laser-associated excitation of electrons and subsequent relaxation of their energy.

We investigated local ferroelectric and piezoelectric properties of nanostructured polymer nanocomposites P(VDF-TrFE)+xBPZT (x = 0-50%) using scanning probe microscopy technique.

Two thick layers of calcium silicide with different compositions have been formed and studied. A procedure of layer-by-layer deposition of Ca at 130 °C and 500 °C on a previously formed layer of amorphous Si or on a polycrystalline Si layer were used. Electronic spectroscopy has shown that Ca₂Si is formed at 130 °C, but Ca₃Si₄ is formed at 500 °C. According to photoreflectance spectroscopy and Raman spectroscopy data the Ca₃Si₄ film grown at 500 °C has a polycrystalline structure, in which strong direct interband transitions at 0.89 and 0.912 eV are observed.

Single molecule spectroscopy of QD-dye nanoassemblies is shown that single functionalized dye molecules (perylene-bisimides and meso-pyridyl porphyrins) can be considered as extremely sensitive probes for studying exciton and relaxation processes in semiconductor CdSe/ZnS quantum dots.

We present calculations of optical absorption spectra of 13-atom bimetallic Ag-Au clusters. All possible chemical configurations of the icosahedral 13-atom cluster are used as starting structures. The spectra are calculated for the lowest energy structures of each composition. On the gold-rich side of the composition spectrum, the absorption is extremely sensitive to addition of Ag. With two Ag atoms, the characteristic peaks disappear. The Ag-rich side is slightly less sensitive to addition of gold. For intermediate compositions, the clusters do not show characteristic peaks, due to both the chemical disorder and the distortion of the structures.

Transparent Er³⁺:PbF₂-containing nanophase glass-ceramics was synthesized by means of heat-treatment of as-cast erbium-doped oxyfluoride glass. Optical absorption of glass and glass-ceramics was investigated in details. Temporal characteristics of luminescence associated with ⁴I_13/2→⁴I_15/2 transition were studied under diode-pumping that results in the determination of decay times. Intense red and green up-conversion emission was obtained with glass-ceramic samples.

An effect of Eu³⁺-precursor on the luminescent properties of GeO₂-Eu₂O₃-Ag films was studied. This effect can be attributed to the different phase compositions of europium compounds after heat treatment and the change of structural parameters of the environment for europium ions.

Electron-electron interactions are shown to cause charge accumulation at the edges of a graphene nanoribbon and also formation of edge states even without magnetic field. The edge states form gradually as the Fermi energy or electron concentration increases. They are immune to defects in interior of a device but can be easily scattered by an edge imperfection. A narrow trench blocks transmission almost completely but for sufficiently long and smooth constriction having a cosine shape the transmission can be improved.

The physical model that allows to calculate tunneling currents between graphene layers is proposed. The tunneling current according to the proposed model is proportional to the area of tunneling transition. The calculated tunneling conductivity is in qualitative agreement with experimental data.

First principles calculations have been performed to investigate ground state properties of monoperiodic carbon nanotubes (CNTs) containing nanochain of Ni atoms inside. Using PBE exchange-correlation functional (E_xc) within the framework of density functional theory (DFT), we predict the fragmentation of Ni nanofilament inside (n,0) CNTs for n > 10, while in (n,n) NTs the nanochain composed from Ni atoms is stable irrespectively on the nanotube diameter. The variations in formation energies obtained for equilibrium defective nanostructures allow us to predict the most stable compositions, irrespectively on the growth conditions. The changes in the electronic structure are analyzed in order to show an extent of localization for the ferromagnetic ground state.

Modelling of ordered arrays of carbon nanotubes (CNTs) accounting for various nonlinear interactions can be realized on the basis of macroelectrodynamics of moving media, theory of elasticity and phenomenological theory of van der Waals interactions. To include van der Waals forces the additional terms are introduced into the balance equations which transform the system into integro-differential form. Integral terms can be neglected if the gap between tubes is greater than CNT outer diameter. Numerical solution showed the essential influence of van der Waals forces on CNT array resonant frequencies.

We have used molecular dynamics simulation to study helium adsorption capacity of carbon nanotube bundles with different diameters. Homogeneous carbon nanotube bundles of (8,8), (9,9), (10,10), (11,11), and (12,12) single walled carbon nanotubes have been considered. The results indicate that the exohedral adsorption coverage does not depend on the diameter of carbon nanotubes, while the endohedral adsorption coverage is increased by increasing the diameter.

A new type of analyzer of laser polarization has been designed. The principle of operation of this analyzer is based on the registration of the polarization-dependent surface photocurrents in single-walled carbon nanotube films. The analyzer does not contain additional optical elements and consists of a cylindrical bushing with a gauge of its angular position, a carbon nanotube film on a substrate, two parallel measurement electrodes on the film surface, and an electrical measuring instrument.

We present the results of quantum chemistry simulation of hyperfine interactions (hfi) between electronic spin of single NV center and arbitrary disposed ¹³C nuclear spins in the NV-hosting H-terminated cluster C₂₉₁NVH₁₇₂. The calculated hfi matrices are used in spin- Hamiltonians to simulate available experimental observations.

A structure of Ge-Se glasses is simulated by the featured clusters built from GeSe₄ tetrahedrons up to the clusters with six germanium atoms (Ge₆Se₁₆H₄ and Ge₆Se₁₆H₈). Quantum chemical calculations at the DFT level with effective core potentials for Ge and Se atoms for the clusters of different composition reveal their relative stability and optical properties.

We present a theoretical study of lateral growth of nanowires and its influence on the nanowire shape during the diffusion-induced growth. Self-consistent growth model allowing us to describe the vertical and lateral growth simultaneously was developed. We find the typical shapes that nanowires adopt under different growth conditions. A comparison between the predicted and experimentally observed shapes of nanowires shows a good quantitative correlation.

We present a kinetic model of self-induced GaN nanowires growth. It demonstrates scaling growth laws and makes obvious the evolution of nanowire length and radius during the growth. The length scales with the radius as L ∝ R^a. Theoretical fits are in a good agreement with experimental results for self-induced GaN nanowires growth.

It is shown that β-FeSi₂ nanocrystall (NCs) can move up to the surface during silicon layer overgrowth (emersion). After studying how emersion depends on a substrate crystalline quality and orientation, silicon overgrowth temperature and annealing, a model of the process was proposed. If the substrate temperature is high enough to provide an intense surface and grain-boundary diffusion of silicon atoms, then silicon layer will grow not only on the surface but also under the NCs. The model is experimentally confirmed.

We report on the core-shell InGaAs/GaAs nanopillars grown by metal organic chemical vapor deposition on silicon substrates. The core diameter is about 600 nm, the shell thickness is around 160 nm, the lattice mismatch is 2%. The transmission electron microscopy studies reveal an excellent crystal quality in the entire pillar with no noticeable defects even though the critical thickness for dislocation formation in GaAs shell is only 10 nm in the thin film case. We developed a theoretical model describing a huge increase of the critical thickness owing to the core-shell geometry.

AFM and FTIR spectroscopy were applied to study the relationship between surface blisters and nanovoids in annealed hydrogenated a-Si. The influence of the H bonding configuration on the way the nanovoids give rise to the blisters is discussed. Annealing causes an increase of the polymers density. As they reside on the voids walls their density increase causes an increase of the voids volume. The polymers may release H inside the voids with creation of H₂ gas, whose expansion, upon annealing, further contributes to the volume increase of the voids till the formation of surface blisters.

Shape memory alloys have a peculiar property to return to a previously defined shape or dimension when they are subjected to variation of temperature. These alloys have the important ability to ‘remember’ their shape and recover this shape after deformation, and they are used as shape memory elements in devices due to this property. The behavior of these materials is evaluated by the structural changes caused by internal stresses in microscopic scale depending on the external conditions. Shape memory effect is facilitated by martensitic transformation, and shape memory properties are intimately related to the microstructures of the alloy, especially the morphology and orientation relationship between the various martensite variants. Twinning and detwinning processes can be considered as elementary processes activated during the transformation.

Simulation of heat distribution inside a porous alumina layer being formed by electrochemical anodization of aluminum has shown that Joule heating of the pore bottom is about four orders of magnitude more intense than that near the aluminum/oxide interface. As a result, microplasma formation is expected in this region.

Conventional superconductivity in bulk objects is characterized by three phenomenological features: zero resistivity, perfect diamagnetism (Meissner effect) and energy gap in the excitation spectrum. In this paper we demonstrate that these attributes of superconductivity do not apply to ultra-small objects governed by the essentially nanoscale phenomenon which is quantum fluctuations. The observation results in fundamental limitations of utilization of superconducting elements in nanoelectronic circuits. However, together with this rather pessimistic conclusion, the indicated size phenomena lead to a new class of nanoscale devices and applications.

The microscopic theory of the bilayer graphene interaction with strong coherent electromagnetic radiation is developed. We consider multiphoton resonant excitation of the Fermi-Dirac sea and subsequent high-harmonics radiation in the bilayer graphene.

A simple but physically consistent model is presented to describe propagation of signals along interconnects made by graphene nanoribbons. The model is derived in the frame of the semi-classical theory. Its parameters are related to the effective number of conducting channels. Finally, a transmission line model is derived and the sensitivity of its parameters is analyzed with respect to the size and temperature change.

Grain boundaries are constitutional elements of graphene grown on a solid metallic surface by CVD. The electronic properties of computer models of grain boundaries in graphene have been investigated by tight-binding calculations and compared with available ab initio data and with recent experimental scanning tunneling spectroscopic measurements. It is shown that twofold coordinated atoms and non-hexagonal rings, both present in grain boundaries, give rise to specific features in the local density of states.

We consider a concept of graphene tunneling transit-time (GTUNNETT) diode, develop its device model, calculate the dc and ac characteristics, and evaluate the GTUNNETT ultimate performance. It is demonstrated that GTUNNETTs can exhibit negative dynamic conductivity in the terahertz (THz) range of frequencies. The GTUNNETs with the optimized structures (proper geometrical parameters and number of graphene layers) can be used in efficient THz oscillators.

We report on the experimental study of electromagnetic (EM) properties of multilayered graphene in K_a-band synthesized by catalytic chemical vapor deposition (CVD) process in between nanometrically thin Cu catalyst film and dielectric (SiO₂) substrate. The quality of the produced multilayered graphene samples were monitored by Raman spectroscopy. The thickness of graphene films was controlled by atomic force microscopy (AFM) and was found to be a few nanometers (up to 5 nm). We discovered, that the fabricated graphene provided remarkably high EM shielding efficiency caused by absorption losses at the level of 35-43% of incident power. Being highly conductive at room temperature, multi-layer graphene emerges as a promising material for manufacturing ultrathin microwave coatings to be used in aerospace applications.

Electromagnetic response of a finite-length multiwall carbon nanotube (MWCNT) of a large cross-sectional radius is theoretically studied in sub-terahertz regime. The diameter dependence of the MCWNT polarizability is studied. The shielding effect in MWCNT due to a strong depolarizing field is demonstrated.

Double-walled carbon nanotubes can reduce plasmon-polariton phase velocity up to 100 times, owing to interaction of plasmon-polaritons of adjacent walls. However, for some applications it is desired to have a less phase velocity. Using many body formalism and tight-binding approach, a dispersion equation for plasmon-polariton in a double-layer graphene was derived. It was found that the double-layer graphene can provide further reduction (up to 300 times less than the speed of light in vacuum), because of equality of plasmon-polariton frequencies in each layer but electron tunneling between the layers prevents that. Such drawback can be eliminated in the system of two spatially separated graphene layers.

We proposed and numerically studied an ultrathin nanostructured plasmonic light absorber with an insulator-metal-insulator-metal architecture, which is polarization independent and capable to absorb up to about 90% of visible light in a broad (300-800 nm) wavelength range. It has a weak incident angle dependence owing to electric field enhancement caused by Bragg diffraction.

Dielectric properties of onion-like carbon and polyurethane composite prepared using different procedures were investigated in the frequency range up to 1 MHz. We show that broadband dielectric spectroscopy is powerful tool to determine technological fingerprints in the studied materials. It is demonstrated that cured samples annealed at temperature close to the melting point (450 K) exhibit substantially higher dielectric permittivity and electrical conductivity in comparison with untreated samples.

The concentration dependence of electromagnetic response properties of epoxy resin filled with small amounts of commercially available high surface area highly conducting carbon black is investigated experimentally and modeled via simple Maxwell-Garnett formalism in the microwave frequency range.

The key point of this study is investigation of nanomechanical properties of epoxy-based nanocomposites filled with different kinds of carbon nanofillers like exfoliated graphite, high surface-area carbon black, single-walled carbon nanotubes and multi-walled carbon nanotubes.

The epoxy resin composites with various carbon additives were investigated in the frequency range of 20 Hz – 3 GHz at temperatures from room to 500 K. The dielectric properties were found to be strongly impacted by percolation threshold. The lowest percolation threshold (< 0.25 wt.%), was observed in composites with single-walled carbon nanotubes.

It was found that nanocomposite film consisting of PEDOT:PSS and functionalized with Au nanoparticles has strong sensing ability to oxygen. The observed phenomenon can be explained in the framework of interaction between functionalized Au and oxygen resulting in their strong interaction with charged polymer blend chains and conductivity increase.

In K_a-band, we observed that nanometrically thin pyrolytic carbon film being only some thousandth of the skin depth absorbs up to 50% of incident power. Theoretical modeling based on Fresnel's formulae and boundary conditions in the rectangular waveguide demonstrates excellent coincidence with experimental data obtained for nanofilms of different thicknesses (5-240 nm).

Fundamental 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 correlated changes of current and spin states. The cluster approach based on the multiple scattering theory as well as an effective medium approximation were used to model the dispersion law, electronic density of states, conductivity, etc. Multiple scattering problems were solved for nanostructures with radial and axial symmetry. Parametrical numerical simulations of conductivity using the formalism of Kubo-Greenwood were carried out for zig-zag (m,0), armchair (m,m) and chiral (m,n) CNTs. The sensitivity of conductivity to the local electronic density of states in CNTs with local impurities (N and B atoms) was demonstrated to be promising for nanosensors.

We report dispersion properties of the surface plasmon polaritons (SPP) in metal-dielectric nanocomposites (MDN). We show that in MDN with a small metal volume fraction the SPP band broadens with an increase in concentration of metal nanoparticles, while in the MDN with a large metal volume fraction, the SPP band splits in two parts.

Complex dielectric permittivity of eight nanoporous metal-organic frameworks (MOFs) is measured for the first time in the short-wavelength region of the millimeter-wave band. The measurements show that these nanoporous materials exhibit either a Debye-type or a damped resonance dispersion. It is established that the dielectric characteristics of the MOFs are significantly changed when the materials are placed in a humid environment. This fact can be used to design sensors to monitor the composition of the surrounding atmosphere.

The effect of different wt.% of ionic liquid “1,6-bis (trimethylammonium-1-yl) hexane tetrafluoroborate” in 0.5 M LiClO₄+PC electrolyte on the supercapacitor properties of polyaniline (PANI) thin film are investigated. The PANI film is synthesized using electropolymerization of aniline in the presence of sulfuric acid. The electrochemical properties of the PANI thin film are studied by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) measurements. The optimum amount of the ionic liquid is found to be 2 wt.% which provides better ionic conductivity of the electrolyte. The highest specific capacitance of 259 F/g is obtained using the 2 wt.% electrolyte. This capacitance remains at up to 208 F/g (80% capacity retention) after 1000 charge-discharge cycles at a current density of 0.5 mA/g. The PANI film in the 2 wt.% ionic liquid catalyzed 0.5 M LiClO₄+PC electrolyte shows small electrochemical resistance, better rate performance and higher cyclability. The increased ionic conductivity of the 2 wt.% ionic liquid catalyzed electrolyte causes a reduction in resistance at the electrode/electrolyte interface, which can be useful in electrochemically-preferred power devices for better applicability.

Non-washing layer-by-layer assembly allows to obtain concentrated (3-5 mg/mL) colloids of 150-200 nm diameter capsules encasing poorly soluble drug nanocrystals or soft gellike nanoparticles. Aggregation of the nanoparticles is prevented by using low molecular weight block-copolymers of poly(amino acids) with polyethylene glycol (PEG) in a combination with heparin and bovine serum albumin at every bilayer building step. Minimal amounts of the polyelectrolytes are used to recharge the surface of nanoparticles in the non-washing LbL process. Such PEGylated shells result in drug nanocapsules with a high colloidal stability in PBS buffer and increased protein adhesion resistance.

The modified sol-gel technique for fabrication of W, Mo, Ni and Co oxides nanopowders and binary mesoporous composites based on them is proposed. It was established the optimal parameters of synthesis of ultradispersed powders with a particle size less than 100 nm: the nature of the sol stabilizer, stabilizer/metal molar ratio value and gel calcination mode. The developed approach enables to synthesize purposefully the metal oxide nanoparticles of a given size with accuracy up to 20-30 nm.

A modified sol-gel technique was developed for fabrication of ultradispersed metal oxides powders of Bi₂O₃, CeO₂, Cr₂O₃, Y₂O₃, ZnO₂ and ZrO₂. Hexamethylenetetramine, monoethanolamine and acetylacetone were used for the sol formation and gel stabilization.

We perform modelling of the organic hexa-iodo-cyclohexa-m-phenylene (CHP) molecule on the h-BN/Rh(111) nanomesh [M Corso et al., Science 132, 217 (2004)]. The nanomesh structure consists of a Moiré pattern with a periodicity of 3.2 nm. It forms a template on which the molecules preferentially adsorb in the lower-lying “pores”. We employ density functional theory in a slab geometry to investigate the adsorption and the abstraction of iodine atoms of the CHP on the nanomesh.

The novel stabilizing ligand, 5-mercaptotetrazole-1-acetic acid, has been applied for synthesis of silver and palladium nanoparticles in aqueous media. The morphology of the synthesized particles and some properties were determined by TEM, FTIR and UV-visible spectroscopy, thermogravimetric analysis and quantum-chemical calculations.

A simple technique for preparation of stable gold colloidal solutions by interaction of tetrachloroauric acid and sodium borohydride in the presence of sodium folate was developed. The morphology of gold nanoparticles and their optical properties were characterized by TEM and UV-visible spectroscopy.

A synthesis method to prepare Fe-Pd composite nanoparticles is presented. Structure and phase composition, morphology and magnetic properties of the obtained powders were studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), ferromagnetic resonance (FMR) and Mössbauer spectroscopies.

TiO₂:MoO₃ nanocomposite materials were synthesized by a colloid-chemical route. SEM, TEM, XRD and IR-spectroscopy indicate availability of specific interactions in TiO₂:MoO₃ system that include disturbance of TiO₂ crystal structure with MoO₃ loading, nanocrystal size effect of the both components, size of coherent scattering regions, and surface acid-base properties. This interaction depends on MoO₃ content in TiO₂:MoO₃ composite and the annealing temperature. Presence of separate highly dispersed particles of MoO₃ in the composite can be a crucial factor for improvement of hydrogen sensing properties of the synthesized material with 1 mol. % of MoO₃.

Ultrafine powders of barium hafnate doped with trivalent cerium were prepared by co-precipitation method with ammonium bicarbonate and oxalate. An influence of the precipitant and annealing temperature on morphology, phase composition and photoluminescent properties of the powders has been studied.

Hydroxyapatite-containing coatings were prepared on a titanium substrate by chemical treatment of the anodic films with TiO₂ nanotube arrays in Ca(OH)₂ and (NH₄)₂HPO₄ solutions using successive ion layer adsorption and reaction. The composite coatings obtained offer a good adhesion to the titanium implant and a high biocompatibility due to embedding hydroxyapatite nanoparticles into the vertical TiO₂ nanopores.

We developed a method to probe local ion concentration with glass nanopipette in which poly(vinyl chloride) membrane containing ionophore for separate ion detection is prepared. Here we demonstrate how ion-selective detections are available for living cells such as HeLa cell, rat vascular myocyte, and neuron cell.

PbS nanoparticles were introduced into mesoporous TiO₂ films on ITO support by successive ion layer adsorption and reaction (SILAR) and photochemical deposition. Potentiodynamic impedance spectra can be discriminated between PbS nanoparticles bound to ITO support directly and via oxide. This provided monitoring of electrical interconnections in nanostructures of different origins.

We synthesized a new type of conjugates of highly luminescent water soluble CdSe/ZnS colloidal quantum dots covalently bound to Chlorin e6 dye molecules. We observed a resonance energy transfer from quantum dots emitting at 660 nm to Chlorine e6 molecules in our conjugates which can be utilized for phototherapy. Contrary to that quantum dots emitting at 588 nm show non-resonance quenching of excitonic luminescence without the energy transfer to dye molecules.

Stoichiometric Mg_0.5Zn_0.5Fe₂O₄ powder was prepared by spray pyrolysis of water solution of inorganic metal salts in the presence of an inert component. Single phase ferrite with a cubic spinel-type structure and predominant grain size of 20-40 nm was observed after subsequent calcination of the powder at 700 °C and removal of the inert additive. Saturation magnetization of the powder was measured to be 32 emu/g at 300 K.

We have analyzed the effect of silicon nanoclusters on the process of proton transfer in a complementary pair of cytosine-guanine. We showed that a free surface of silicon nanoclusters causes variation of the stability (increases stability) of the tautomeric cytosine-guanine complementary pair. As a result a nanoparticle with a free surface could lead to the point mutations of DNA.

Quantum-chemistry projecting of the carborane and fullerene nano-cluster agents has been carried out. These agents contain or transform into radio-nuclides under the effect of neutron radiation that apply for oncological diagnostics and therapy.

This paper reviews electrochemical processes for the application in 3D through-silicon via fill technology. Electroplating, electroless plating and electrografting techniques are being investigated for barrier/seed and Cu superfill. Replacement of poor step coverage PVD barrier/seed with conformal electroless barrier/seed and low bottom up fill rate acceleration-based electroplating with superfill suppression-based electroplating will allow defect free-fill of high aspect ratio vias. Integration of electroless plating and electroplating will enable all-wet through-silicon via fill that exceed current fill techniques in scalability at lower process cost.

Interesting phenomena during Au-assisted chemical beam epitaxy of InAs-InSb nanowire heterostructures have been observed. We observed an unusual nanowire density dependence of InSb nanowire length and rare non-monotonous type of the length-diameter dependence. Novel theoretical model of nanowire growth has been developed, which includes the contribution of readsorbtion of desorbed material from neighboring nanowire sidewalls.

Layered compounds, like MoS₂ were shown by the author to be unstable in the nano-regime. Using new chemical strategies, closed-cage hollow nanostructures in the form of inorganic fullerene-like nanoparticles and inorganic nanotubes were synthesized. These nanostructures exhibit numerous interesting physico-chemical properties and are employed as superior solid lubricants, with numerous other applications currently being developed.

A series of in situ TEM experiments to study the electron irradiation effect on SiO_x/Pt hybrid nanomaterial has been carried out. First, SiO_x/Pt was changed into Pt-silicide under electron irradiation to be the same one formed by thermal processing. The silicide formation was confirmed to proceed below room temperature.

Double-walled TiO₂ nanotubes have been fabricated for the first time by anodization of Ti foil or film providing a layer of densely packed single-walled TiO₂ nanotubes with a diameter of 100-250 nm and their subsequent annealing at 450 °C to split the tubes into two concentric tubes. Peculiarities of the tubes structure and possible mechanism of their formation are discussed.

We report on a facile and efficient approach to porous aluminum anodization, which has been realized under high forming voltages with Joule heat sink through aluminum tracks formed by a photolithographic mask. Record high forming voltages at room temperature have been achieved leading to a new tubular oxide structure with the tube diameters of 50-400 nm and the anodic process anisotropy of 0.8.

Anodization of TiAl₂ films, fabricated by annealing of magnetron deposited Al-Ti nanostructured composite films at 600 °C, provides formation of a porous film mostly consisting of straight and smooth tubes of about 60-70 nm in diameter. Whereas anodization of as-deposited films leads to a porous film with a strongly marked grain structure and curved vertical pores.

Nanostructured silicon films were fabricated by magnetron sputtering of an Al+Si composite target with a subsequent selective etching off the aluminum phase from the deposited film. It is shown that the film structure consists of silicon submicron conglomerates of 60-160 nm, which in turn are composed of nanoscale grains arranged as a “bunch of grapes”. The regularities of the nanostructured silicon film formation are discussed.

Structures and fabrication features of membranes based on high-ordered matrices of free nanostructured anodic porous alumina with open-ended pores without the barrier layer were designed and discussed. The special combined method composed of the smooth slow voltage drop at the final stage of the two-stage anodization with the cathode polarization and with the alumina chemical etching for the barrier layer thinning and removal was developed. These membranes are promising for different applications because of their manufacturability, capability of reproducing and regularity of the structure parameters.

Dependences of the chemical etching of dense anodic alumina films with the simultaneous recording of a steady-state electrode potential and the film thickness are discussed. The film was determined to have up to 6 characteristic layers differing in the thickness and in the chemical dissolution rate. The procedure proposed is an express method to study characteristic layers throughout the oxide film thickness.

An original way of flexible polymer substrates modification by composite films of polymethylmethacrylate/polyethyleneimine/2,4-heneicosanedione has been developed. The increase of filtration efficiency has been demonstrated on the example of «Vladipor» membranes modified by SiO₂ nanospheres monolayer with mono- and multilayer films of the above mentioned composition.

Contributions of relevant heat and mass transfer processes and characteristic times in nanoparticles production during evaporation of droplet solution are discussed. Low-temperature transformation of aqueous solution of NiCl₂ into nickel oxide nanoparticles is obtained. Classification of morphologies of obtained ensembles of nanoparticles is developed. Details of electrostatic deposition of droplets on metallic substrate are reported.

We have investigated the effect of laser pulse fluence on the characteristics of silver nanoparticles. Ag nanoparticles were synthesized by pulsed laser ablation in distilled water. The optical properties and the size distribution of the suspension are studied with UV–vis absorption spectroscopy and dynamic light scattering, respectively. The shape of the nanoparticles is investigated by scanning electron microscope.

Measurement and analysis of the emitted blackbody-like radiation from laser heated gold nanoparticles in a solution were performed and dominant cooling processes were identified. The temperature of laser heated particles was determined.

By using solid–phase pyrolysis of Ni-phthalocyanine we have synthesized nickel-carbon nanocomposites with the mean diameter of Ni nanoparticles of 45 nm. The composition and structure of the samples were investigated by scanning and transmission electron microscopy and X-ray diffraction. Magnetic characteristics of the nanocomposites were measured with a vibrational magnetometer. The major fraction of the nanoparticles is single-domain ferromagnetic in the temperature range of 6-300 K, while a small fraction is in a superparamagnetic state with blocking temperatures below 25 K.

Liquid phase exfoliation of natural graphite to produce high quality micron scale multilayer graphene sheets (flakes) in two different solvents (n, n - dimethylformamide and isopropyl alcohol) has been studied. The effects of process parameters (basically, sonication time, bath temperature, and centrifugation time) have been investigated. By adjusting the process parameters, high-density solutions containing graphene sheets with lateral sizes from 0.5 to 10 μm (with lateral size-to-thickness ratios up to 300) were obtained.

Graphene films were synthesized by the single injection and fast evacuation of acetylene on polycrystalline nickel catalyst films. They were transferred to a SiO₂/Si substrate using PMMA. Raman spectra and mapping images were used for characterization of the films. It was found that nearly 95% of the Raman spectra show a hallmark of monolayer/bilayer graphene. The transport properties of the films were investigated with Hall measurements.

Formation conditions of the fullerene based composite material with a homogeneous distribution of bioactive particles are defined. An influence of C₆₀(FeC_p2)₂ particle size on the proliferative activity of stem cells is discussed.

Multiwalled carbon nanotubes were synthesized in high isostatic pressure (HIP) apparatus in nitrogen at 1650 °C and 2 MPa. The synthesis was performed with nanodiamonds as a precursor of carbon and with ferrocene as a catalyst. Transmission electron microscopy studies demonstrate that the product of the synthesis contains carbon nanotubes filled with iron-based nanoparticles. It was established that in the most of the cases these nanoparticles represent themselves iron carbide Fe₃C (cementite). Several times we observed pure iron (γ- and ε-Fe) inside the nanotubes. The orientation of the iron and iron carbide particles with respect to the nanotubes axes was investigated.

A pre-deposited tantalum thin film on a Si(100) substrate was treated by compression pulsed plasma flow. SEM images demonstrated the formation of spherical clusters with multi-level structures. Formation of crystalline metal rich tantalum silicides is confirmed by X-ray diffraction and EDX elemental map analysis. The results show great potential application of compression plasma flow for the development of novel nanostructured metal-silicide materials.

Nanocrystalline coatings based on Ti-Zr-N system were reactively sputter-deposited. Xe ion irradiation did not change the phase composition of coatings. The distribution of implanted ions appears to be asymmetric with a shift into the film depth. The peak concentration is 4.7 at.% for ZrN. The smallest experimental projected range (R_p) and straggle (ΔR_p) of xenon ions was found for TiZrN film. The increase in electrical resistivity caused by radiation defects at the ion dose of 5×10¹⁶ cm⁻² is higher for the ZrN nanocrystalline films (ΔR/R=160%) than for the TiZrN film (ΔR/R=74%).

We present hydro-thermally synthesized group I-doped ZnO nanowires (NWs) using an aqueous solution with group I nitrates as dopant sources at low temperatures. The ZnO NWs were prepared on ZnO seed layers. The structural features of various ZnO NWs are discussed.

Density, microstructure and microhardness have been investigated for samples, sintered from submicro-α-SiC and micro-SiC powders as well as their mixtures with addition of 50 vol.% α-Si₃N₄ nanopowder in the temperature interval 1500-2000 °C under pressure of 4 GPa. The dispersed silicon carbide submicron powder and the composite of submicro-SiC/nano-Si₃N₄ powder mixture have the most homogeneous microstructure and the higher hardness (respectively, up to 24 GPa and 22 GPa).

Laser pulse energy is shown to influence characteristics of Au nanoparticles (NPs) produced by laser ablation. Au NPs were formed with spherical shape and different size depending on the laser pulse energy. UV–Vis-NIR spectroscopy revealed the changes of surface plasmon resonance features with respect to size and number of NPs.

We reported the synthesis and surface-enhanced Raman scattering (SERS) effect of silver nanoparticles (NPs) by using laser ablation in liquids. The as-synthesized silver NPs exhibit super SERS sensitivity.

An influence of precursor heat treatment conditions and concentration of the activator on luminescent properties of Lu₃Al₅O₁₂:Ce(III) (LuAG:Ce) nanopowders is studied. The powders were produced by the colloidal-chemical method. The maximum intensity of luminescence was observed for the samples containing 1 at.% Ce(III) prepared at the same conditions of heat treatment. The luminescence intensity increases for all samples with the increase of heat treatment temperature.

Electrical conductivity of aqueous suspensions based on aluminum nanopowder and citric acid solution (20 g/l). The correlation between nanoparticles concentration and abating conductivity of suspensions has been demonstrated during the agglomeration of the aluminum nanoparticles. For the studied suspensions with different concentrations of nanoparticles the smallest conductivity was found after which the particles aggregates begin to deagglomerate due to the high diffusion mobility of the carboxyl groups in the acid medium.

A morphology model is suggested for nano-powdered hexagonal boron nitride that can serve as an effective solid additive to liquid lubricants. It allows to estimate the specific surface, that is a hard-to-measure parameter, based on average size of powder particles. The model can be used also to control nanoscale wear processes.

Mechanical properties of composite monolayers of triacontanoic acid (TA) with MoS₂ and SiO₂ particles formed on silicon surfaces by Langmuir-Blodgett (LB) technology were studied. TA monolayer with MoS₂ particles possessed highest endurance against mechanical influence of a steel ball indenter.

We used annealing in hydrogen atmosphere to produce silver nanoisland films on the surface of silver-enriched silicate glass. Silver ions were introduced in the glass in the course of silver-sodium ion exchange. Penetration of hydrogen into the glass resulted in silver ion reduction and both bulk clustering and out-diffusion followed by surface clustering and nanoisland silver film formation. Characterization of the film with atomic force microscopy and optical absorption spectroscopy allowed us to establish relationships between film parameters and the mode of annealing. We also compare results of the measurements and the developed model based on the equations of reactive diffusion followed by neutral silver nucleation and growth of the nuclei. Formation of 2D structured nanoisland film when used poling of glass with profiled electrode before processing in hydrogen is demonstrated.

The last years have seen several major discoveries in the study of photosynthesis with a potentially large impact on the development of bio-inspired nanosciences. These discoveries include important aspects of different enzymes responsible for various reactions, notably the reaction that allows the photolysis of water. This makes possible important steps towards the realization of systems able to produce hydrogen and oxygen from water using light and also for non-polluting fuel cells. A second group of discoveries concerns the way light is concentrated in photosynthetic systems. This biological concentration system has been found in some circumstances to rely on long distance quantum effects, of interest both for the production of high efficiency photovoltaic devices, and for the production and evolution of quantum computing systems.

In this communication, we first introduce selected approaches, concepts and technological strategies to control incident light collection and absorption in photovoltaic solar cells. We illustrate the interest of light trapping by photonic crystals with examples of structures and devices developed in our group, including amorphous silicon and crystalline ultrathin layer solar cells. Finally, we discuss an interest of photonic crystal structures for the 3rd generation of solar cells using optical processes like down conversion.

We present the most studied piezoelectric materials at the nanoscale and discuss their vertical integration into harvesting devices. Finite element method (FEM) simulations are used to obtain optimization guidelines rules of a specific design.

Conjugated systems 1-5 built by connecting a triphenylamine core with a dicyanovinyle electron-accepting moiety are described. Their spectroscopic and electrochemical properties are discussed as well as the performances of corresponding organic photovoltaic devices. Conversion efficiencies attaining nearly 3% before optimization are obtained with some of these compounds. Differences in efficiencies in devices are rationalized in term of nanostructuration of materials.

Mesoporous In₂O₃ films have been spectrally sensitized with CdS nanoparticles using successive ion layer adsorption and reaction. The samples were characterized by photoelectrochemical, UV-Vis and micro-Raman spectroscopy. Quantum-confinement effects in CdS nanoparticles and their interaction with In₂O₃ substrate were investigated.

Electrodeposition of SnS in porous anodic Al₂O₃ and onto nanotextured Al substrates has been shown to provide formation of the single-phase polycrystalline SnS. Better crystallinity is obtained on the Al substrates.

A new way to access to the open circuit voltage of organic photovoltaic cells with the Kelvin probe force microscopy is presented.

Investigation of influence of Mo deposition on glass substrates by SIAD on its surface topography and wettability was conducted. We observe several steps in the process of the film growth. Contact angle measurements showed that deposition of the Mo films on glass makes the surface less hydrophilic. With an increase of the irradiation dose, the roughness and contact angle increase rapidly at first and then decreases.

The aim of this work was to develop suitable materials to store hydrogen in a solid state. A systematic investigation of the co-milling process of magnesium hydride with a transition metal was undertaken in order to produce nanostructured and highly reactive powders. The initiating role of the transition metal was evidenced by in situ neutron diffraction experiments. High performances in terms of thermal and mechanical behavior were achieved introducing expanded graphite and compacting the mixture to form composite materials. Absorption and desorption kinetics have been measured versus temperature and H₂ pressure.

Thermal desorption mass-spectrometry has been applied to study hydrogenation and hydrogen desorption from multiwall carbon nanotubes. Experimental results are compared with the theoretical data on their atomic and electronic structures revealed by molecular dynamics and quantum chemical calculations.

Novel CeO₂-TiO₂ photocatalysts were fabricated from inorganic precursors as nanocomposites with various CeO₂/TiO₂ molar ratios. X-ray diffraction (XRD) analysis and optical reflection spectroscopy reveal the formation of two types of composites based on CeO₂ or TiO₂ cores in the cases of low or high CeO₂ content, respectively. Both types of nanocomposites possess the higher photocatalytic efficiency than blank TiO₂. Their optical features can provide the activity with irradiation in the visible range.

The photocatalytic degradation of Rhodamine C under UV illumination of titanium dioxide deposited into mesoporous anodic alumina films has been investigated. A complete photomineralization of the dye was observed along with accompanying stepwise cleavage of diethylamino groups without changing the chromophore structure.

Sol-gel derived titania in porous anodic alumina film has been demonstrated as an efficient photocatalytic coating. Its photocatalytic performance after calcination at 400 °C correlates with the size of the pores and the thickness of the porous alumina film providing strong photocatalytic activity for the porous alumina films of 1.5 μm thickness with a size of the pores of 60-70 nm after deposition of the titania xerogel.

The influence of the orientation of lamellar crystallites in nanographite (NG) films on the efficiency of photovoltaic conversion of pulsed laser radiation has been studied. The initial orientation of NG crystallites is perpendicular to the substrate surface. A change in their orientation leads to the incidence angle photovoltaic response anisotropy. The results obtained can be used to design insensitive to the laser power fluctuation angle sensors.

First principles calculations have been performed to investigate ground state properties of monoperiodic TiO₂ and SrTiO₃ single-walled nanotubes containing extrinsic point defects. The hybrid exchange-correlation functionals B3LYP and B3PW within the framework of density functional theory have been applied to calculations for nanotubes with the following substitution impurities: C_O, N_O, S_O, and Fe_Ti. Variations in the formation energies obtained for equilibrium defective nanostructures allow us to predict the most stable compositions, irrespectively of the changes in growth conditions. Changes in the electronic structure show mid-gap states induced by defects.

We synthesized CuInSe₂ nanoparticles using electrical discharge processing of a mixture of copper, indium, and selenium powders in ethanol. Their band gap energy was estimated to be around 1.2 eV using the optical absorption spectroscopy. XRD pattern clearly showed three main peaks of chalcopyrite tetragonal nanoparticles with a size of 30-50 nm.

Investigation of influence of Xe⁺ irradiation on composition of crystal CuInSe₂ surface layers by Rutherford backscattering and channeling was conducted. In the paper we represent concentration changes of Se, In and Cu atoms in the surface layers of crystal CuInSe₂.

In this paper, we present a comparative research of the nanoscale modification of the surface morphology of polycrystalline SnS films on glass substrates with two different preferred growth orientations processed in inductively coupled argon plasma. We report a new effect of polycrystalline SnS film surface smoothing during plasma treatment, which can be advantageous for the fabrication of multilayer solar cell devices with SnS absorption layers.

The incorporation of colloidal quantum dots (QDs) into sol-gel oxide matrices as well as into ionic crystals of various ionic salts is demonstrated. The resulting all-inorganic composites preserve the strong luminescence of the incorporated QDs. Moreover, the inorganic materials appear to be very robust matrices, ensuring the protection of the QDs from the environment and as a result providing them with extraordinary high photo-, thermal and chemical stability. Application potential of such kind of nanostructures for optoelectronics is discussed.

Field emitting CNT cathodes was achieved by CVD with catalytic pyrolysis of hydrocarbon mixtures on localized catalyst. SEM investigation showed that cathodes consist of CNT arrays with clean spacing. Maximum stable currents about 100 μA and 50 μA were achieved during testing in local mode with the anode diameter of 150 μm.

The effect of 170 keV iron ion implantation on the structural properties of arrays of aligned carbon nanotubes (CNTs) grown by floating catalyst chemical vapor deposition on top of Si substrate has been investigated. The implantation was performed at room temperature with the ion dose of 1017 ions/cm2 in the longitudinal direction of CNTs. Scanning electron microscopy (SEM) indicated changes of the top (∼3 μm) layer of the CNT array where CNTs agglomeration was observed. Transmission electron microscopy (TEM) and Raman spectroscopy showed that CNTs in this layer were transformed into amorphous carbon nanofibers dotted with nanoparticles inclusions.

Thin films of C₆₀ polymer were synthesized via electron-beam dispersion (EBD) of a target made of pristine fullerite. Fullerene ion assistance during film deposition resulted in disordered covalent cross-linking of the film material. Electron transport properties of the films were studied in situ and ex situ after the air exposure. Resistivity of the cross-linked film is several orders of magnitude lower than that of nonpolymerized C₆₀ films. UV-Vis absorption spectra of the films showed that cross-linking leads to a significant decrease of the optical gap and increase of the Urbach tail parameter. Electron-transport and magnetic properties of the films were studied in micro- and nanoscale using SPM techniques.

Comparable studies of phase composition, dispersity and magnetic properties of Sr₂FeMoO_6±δ powders obtained by the solid-phase synthesis and the modified sol-gel method have been carried out. The powder obtained by the solid-phase synthesis has high phase purity with the concentration of antistructural defects of 17%. The sol-gel synthesis allows obtaining the large fraction of nanoparticles (≥ 60%) with highly coercitive magnetic inclusions.

Lanthanum doped lead zirconate titanate relaxor ceramics with (Pb_0.91La_0.09) (Zr_0.65Ti_0.35)O₃ composition exhibits a repolarization induced by electroluminescence (EL) with a pronounced discrete character of emission. It is established that this behavior is related to the reorientation of nanodimensional polar regions in a strong pulsed electric field in the vicinity of a smeared phase transition. The time and temperature dependences of the EL intensity are studied.

SERS-active substrates have been fabricated by immersion deposition of Ag on mesoporous silicon. The SERS intensity has been found to alter simultaneously to the periodical repacking of Ag particles which grow according to the Volmer-Weber mechanism. We have determined the crucial parameter (“effective time”) for managing the SERS signal intensity. “Effective time” has been calculated as a product of the immersion time by the Ag salt concentration.

We present results of hydrothermal deposition of undoped and Al doped ZnO nanocrystals on nanocrystalline silicon. ZnO nanocrystals were deposited in an equimolar zinc nitride and hexamethylenetetramine solution. Aluminum nitride was used as Al precursor. The difference of the morphology of doped and undoped ZnO nanocrystals is discussed. Photoluminescence properties of the obtained nanocrystals are shown.

Annealing of shungite is studied in oxidizing conditions in a chamber with NH₄Cl, and in vacuum at 900 °C for 2h. Frequency dependencies of transmission and reflection coefficients of annealed shungite are measured in the frequency range of 8-12 GHz. The minimum reflection at 8-10 GHz was shown for shungite annealed in the oxidizing atmosphere.

The mechanisms of improving the figure of merit Z and power parameter W of thermoelectric materials (TEMs) in the transitions λ_ph→a and λ_e→a are considered (Here λ_ph and λ_e are the mean free path of the phonons and electrons in the sample, and a is the inter atomic distance). It is shown that the same mechanisms are responsible for the growth of Z and W crystalline TEMs at high temperatures.

The theoretical analysis of the electronic excitation energy transfer in the complexes between water soluble CdSe/ZnS quantum dot (QD) and 5, 10, 15, 20-tetrakis(4-N-methyl-pyridyl) porphyrin Zn complex (ZnTMPyrP⁴⁺) has been performed. Quantum chemical methods have been applied to check a possibility of electron transfer processes in this system. The quantum yield and the lifetime of the QDs luminescence in this system are shown to be determined not only by excitation energy transfer but additionally by photoinduced electron transfer from QD to porphyrin and from passivating moieties of mercaptocarboxylic acids S⁻(CH₂)_nCOO⁻ to QD.

Optical absorption and photoluminescence of novel PbS-quantum-dot-doped alumino-alkali-silicate glasses was investigated. PbS nanocrystals with an average diameter of 3.3-5.4 nm were obtained by heat-treatment of the as-cast glass. An influence of temperature (490-510 °C) and duration (10-80 h) of heat-treatment on the optical properties of the glasses was studied. A possibility to shift the maximum of 1S–1S excitonic absorption peak in the spectral range of 0.85-1.4 μm was demonstrated.

Si/SiO₂ channels filled with Ag clusters have been realized by applying of the swift heavy ion tracks and electroless wet-chemical deposition technologies. Microstructure and morphology have been investigated using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). An exploitability of silver nanostructures in surface enhanced Raman spectroscopy (SERS) has been discussed.

An explanation of resistive characteristics broadening of the superconducting phase transition in Nb/Pd_0.81Ni_0.19 multilayers has given based on the concept of multiple order parameter configurations. Peculiarities of the ferromagnetic layers have also taken into account.

We report results of transport measurements on patterned Nb/PdNi bilayers. The critical current is shown to depend on the magnetic prehistory. After application of the strong perpendicular magnetic field the critical current becomes significantly less than for virgin sample. Application of the parallel magnetic field influences less the absolute value of the critical current. The observed behavior can be accounted for by the magnetocrystalline anisotropy of thin PdNi layer oriented out-of-plane, generating the spontaneous vortex phase inside the superconducting layer.

Here we present two new approaches to develop high-sensitive optical sensors of relative humidity and chemicals in ambient medium. Relative humidity sensors are designed as waveguide layer formed by hydrophilic polymer. Optical chemical sensors are based on modification of an optical waveguide by nanostructured biopolymer doped with a chemically sensitive optical material.

Light emitting nanostructures on the basis of (Al, Ga, In)N solid solutions with and without superlattices were investigated. Experiments in a wide range of temperatures (10-300 K) and currents (10 nA - 2 mA) were done. Comparison of structures with and without superlattices was performed. It was found that the structure with superlattices has higher stability and better work performance. Apparently, the use of superlattices can reduce an influence of elastic stresses and piezoelectric fields at the heterointerface. This may decrease the formation of dislocations, which increases the intensity of radiation and decreases self-heating effects.

We have modified a monolayer graphene sheet to oxidized graphene electrochemically using local anodic oxidation by atomic force microscope. Graphene oxide was successfully formed in line and square shape at various bias voltages and scan speeds.

SERS-active arrays of bimetallic nanovoids have been fabricated by Ni electrochemical plating followed by Ag immersion deposition on macroporous silicon (PS). Presence of HF in the solution for Ag deposition has been found to result in fabrication of the SERS-active substrates with 20 times enhanced Raman intensity in comparison with those formed in HF-free solution. The detection limit of R6G adsorbed on the bimetallic substrates has been determined to reach 10⁻¹¹ M.

A microelectromechanical system (MEMS) has been fabricated by using a well-developed silicon oxidation process. This system includes combustion chambers formed in macropores of a silicon substrate, nozzles based on pyramidal pits and nanoporous silicon impregnated by solid state oxidants as a fuel. The estimated impulse of such a MEMS reaches 10 mN·s that is the highest value up to date.

Nanoporous anodic alumina substrates were developed and tested for low-power chemical sensors. A model describing the processes in the sensors was proposed. A chemical sensor on nanoporous alumina substrate with In₂O₃+Ga₂O₃ sensitive layers was fabricated and investigated. The sensor sensitivity to CO and H₂ was up to 109.68% and 154.17%, respectively.

The ferromagnetic effect of delta<Mn> doping of a GaAs barrier on the properties of InGaAs/GaAs quantum well heterostructures has been investigated. It has been shown that the galvanomagnetic properties and circular polarization of electroluminescence of the samples are strongly correlated. The possible mechanisms of the effects observed are discussed on the basis of the technology parameter variation affecting the ferromagnetic properties.

The volumetric-surface variant of the capacitive MDM (metal-dielectric-metal) structure of the vertical direction based on high-ordered matrices of free anodic porous alumina membranes for applications in humidity sensing elements was designed. The improved humidity sensitivity, reduced response and recovery time over a wide humidity range were obtained due to alumina membranes with open-ended and widened pores without the barrier layer. It allows to eliminate the effect of the electrolyte anions embedded in pore walls on the adsorption/desorption processes.

An effect of particle size, concentration of structural defects and the presence of sulfite and sulfate groups on the response of thick-film SnO₂ sensors to CH₄ and CO was revealed. Particle size and the presence of SO-groups were found to be main parameters determining the sensitivity of SnO₂-based sensors to CH₄, while structural defects of SnO₂ layers are essential for CO detection.

We have considered size effects of silicon/germanium nanoclusters on the hysteresis of C-V characteristics of metal-insulator-semiconductor structures where silicon nitride doped by lanthanum is uses as a dielectric. Critical size of 70 nm is suggested for nanoclusters for efficient performance of non-volatile memory.

We consider the combined influence of the dynamic frequency shift of the absorption line and nonlinear phase relaxation on the quantum dot lasing.

The following sections are included:

• AUTHOR INDEX