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Powder composites of hydrogenated eutectic Mg–Ni alloy with 10 wt % graphene-like material (GLM) were prepared mechanochemically at a hydrogen pressure of 30 atm. The effect that adding GLM, along with 10 cycles of desorption at 350°C and 1 atm and sorption at 300°C and 10 atm of hydrogen, has on the phase composition and microstructure of the composites is studied. It is shown that composites obtained mechanochemically (hbm composites) and subjected to cycles of hydrogen desorption–adsorption (dh composites) contain crystalline phases: α-MgH2 with rutile-type structure, Mg2NiH4 hydride with a disordered cubic structure (pseudo-ht-Mg2NiH4), and a solid solution of hydrogen Mg2NiH≤0.3. It is found that in hbm composites with GLM additives, the content of the pseudo-ht-Mg2Ni phase is higher than in composites without carbon additives. The Mg2Ni(H) and Mg(H) particles have a common boundary in composites, and cycling does not affect these features of the microstructure. The presence of GLM preserves the small particle sizes of both phases during cycling.

The technique of simultaneous coagulation of two different materials in superfluid helium has been implemented, which allows one to create different ultrathin (d < 8 nm) heterostructures. A simultaneous ablation of two metal targets (indium and platinum) immersed in the volume of superfluid helium and targets carried out above the surface of the liquid has been performed. During the ablation of targets in the volume of helium, nanowires from individual metals are obtained. During the ablation of targets located above the surface, in addition to nanowires of individual metals, “combined” nanowires are formed when the wire from indium coaxially overlap the platinum wire.

Using transmission electron microscopy and UV–Vis spectroscopy, the effect of the concentration of the silver oligostyrylmonocarboxylate precursor in the range of 0.3–3.2 wt % in the reaction with the ED-20 epoxy resin on the formation of silver nanoparticles at a temperature of 75°C is studied. At the initial carboxylate concentration ≤0.3 wt %, silver nanoparticles with oligostyrylmonocarboxylate ligands having a spherical shape, small size, and narrow dispersion are produced. With an increase in the initial concentration of silver oligostyrylcarboxylate ≥0.3 wt %, the accumulation of nanoparticles is accompanied by the appearance of aggregates of arbitrary shape due to the van der Waals interaction of carboxylate ligands. The presence of aggregates leads to the broadening, splitting, and redshift of surface plasmon resonance peaks. Silver nanoparticles in aggregates are separated by ligand shells that reduce the probability of coalescence.

The main problems with the liquid-phase technology of carbon fiber/aluminum matrix composites include poor wetting of the fiber with liquid aluminum and formation of aluminum carbide on the fibers’ surface. This paper aims to solve these problems. The theoretical and experimental dependence of porosity on the applied pressure were determined. The possibility of obtaining a carbon fiber/aluminum matrix composite wire with a strength value of about 1500 MPa was shown. The correlation among the strength of the carbon fiber reinforced aluminum matrix composite, the fracture surface, and the degradation of the carbon fiber surface was discussed.

Because of their unique atomic structure, 2D materials are able to create an up-to-date paradigm in fundamental science and technology on the way to engineering the band structure and electronic properties of materials on the nanoscale. One of the simplest methods along this path is the superposition of several 2D nanomaterials while simultaneously specifying the twist angle between adjacent layers (θ), which leads to the emergence of Moire superlattices. The key challenge in 2D nanoelectronics is to obtain a nanomaterial with numerous Moire superlattices in addition to a high carrier mobility in a stable and easy-to-fabricate material. Here, we demonstrate the possibility of synthesizing twisted multilayer graphene (tMLG) with a number of monolayers NL = 40-250 and predefined narrow ranges of θ = 3-8°, θ = 11-15°, and θ = 26-30°. A 2D nature of the electron transport is observed in the tMLG, and its carrier mobilities are close to those of twisted bilayer graphene (tBLG) (with θ = 30°) between h-BN layers. We demonstrate an undoubtful presence of numerous Moire superlattices simultaneously throughout the entire tMLG thickness, while the periods of these superlattices are rather close to each other. This offers a challenge of producing a next generation of devices for nanoelectronics, twistronics, and neuromorphic computing for large data applications.

The mechanism of cross-hatch (CH) pattern formation on the surface of GaMnAs/InGaAs/GaAs (001) heterostructures with a small lattice mismatch, related to the peculiarities of glide process of dislocations in epilayers, is considered. Electrically active defects in these heterostructures and the surface morphology of epilayers were investigated by electron beam induced current imaging, transmission electron microscopy (TEM), atomic force microscopy and differential interference contrast microscopy in combination with selective chemical etching. The studies revealed a high-density system of extended defects (EDs) in the bulk of InGaAs epilayers in addition to misfit dislocations at the epilayer/substrate interface. These defects possess a number of properties reflecting their unusual core structure: pronounced crystallography, recombination activity, existence of elastic strains in the core, and at the same time the absence of contrast in the TEM images. Model experiments performed on InGaAs epilayers give grounds to consider that the revealed EDs are similar in properties to a new type of EDs generated by moving dislocations in plastically deformed Si and SiGe crystals. The formation of CH surface structure is assumed to be directly related to the emergence of the EDs during the strain relaxation process in heterostructures based on III-V and IV-group materials.

Two-dimensional polymers are highly promising materials for microsystems technologies and fundamental science. Some of the most interesting, but relatively unstudied, materials of this kind are polyphthalocyanines. These are a unique class of organometallic polymers with a two-dimensional conjugated structure and variable electronic properties. Since polyphthalocyanines of a high degree of polymerization can be obtained only as thin films and not as a bulk crystal, their study and characterization is a complicated scientific challenge. In this work we demonstrate the potential of transmission electron microscopy as a key tool in characterizing thin films. In particular, transmission-electron-microscopy data provide a basis for interpreting the Raman spectra of polyphthalocyanines, and also make possible interpretation of the crystal structure of the two-dimensional polymer.

A novel one-pot chemical synthesis of functional copper iodide-polypyrrole composites, CuI-PPy, has been proposed. The fabrication process allows the formation of nanodimensional metal salt/polymer hybrid structures in a fully controlled time- and concentration-dependent manner. The impact of certain experimental conditions, viz., duration of synthesis, sequence of component addition and concentrations of the intact reagents on the structure, dimensionality and yield of the end-product was evaluated in detail. More specifically, the amount of marshite CuI within the hybrid composite can be ranged from 60 to 90 wt.%, depending on synthetic conditions (type and concentration of components, process duration). In addition, the conditions allowing the synthesis of nano-sized CuI distributed inside the polypyrrole matrix were found. A high morphological stability and reproducibility of the synthesized nanodimensional metal-polymer hybrid materials were approved. Finally, the electrochemical activity of the formed composites was verified by cyclic voltammetry studies. The stability of CuI-PPy composite deposited on the electrodes was strongly affected by the applied anodic limit. The proposed one-pot synthesis of the hybrid nanodimensional copper iodide-polypyrrole composites is highly innovative, meets the requirements of Green Chemistry and is potentially useful for future biosensor development. In addition, this study is expected to generally contribute to the knowledge on the hybrid nano-based composites with tailored properties.

We report new carbon-based coating that can be utilysed as a hard chemically inert highly condictive transparent blanket for electrodes and moving parts in a wide range of electronic and MEMS applications. Diamond-like carbon film was grown on (100) n-Si substrate by accelerated C60 ion beam irradiation. Ion energy was kept at 5 and 8 keV, substrate temperature was varied in the range 100–400 ℃. Irradiation with 5 keV beam results in growth of carbon films at all temperatures used. Films are amorphous with high amount of sp3-bonded carbon atoms. Graphite nanocrystals of ~1.5 nm in size were found in the coatings grown at 400 ℃. 8 keV beam sputters the Si target at 100 and 200 ℃, while bombardment at higher temperatures (300 and 400 ℃) results in carbon film growth. Graphite nano-crystal formation is much less pronounced at this energy. In all cases, silicon carbide interlayer is formed at the substrate-coating interface due to the ion-beam mixing effect, which results in a good adhesion of the coating. Electric resistivity of coating obtained with 8 keV ions at Ts = 400 ℃ is 1.5 × 10−4 Ω × m, whereas 5 keV ions at same Ts = 400 ℃ gives 9 × 10−4 Ω × m.

ACS omega 5(18), 10441-10450 (2020). doi:10.1021/acsomega.0c00391, We present the fabrication and investigation of the properties of nanocomposite structures consisting of two-dimensional (2D) and three-dimensional (3D) metallic nano-objects self-organized on the surface and inside of organic molecular thin-film copper tetrafluorophthalocyanine (CuPcF$_4$). Metallic atoms, deposited under ultrahigh vacuum (UHV) conditions onto the organic ultrathin film, diffuse along the surface and self-assemble into a system of 2D metallic overlayers. At the same time, the majority of the metal atoms diffuse into the organic matrix and self-organize into 3D nanoparticles (NPs) in a well-defined manner. The evolution of the morphology and electronic properties of such structures as a function of nominal metal content is studied under UHV conditions using transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and photoelectron spectroscopy (PES) techniques. Using HR-TEM, we have observed the periodicity of atomic planes of individual silver NPs. The steady formation of agglomerates from individual single nanocrystallites with intercrystallite boundaries is observed as well. PES reveals generally weak chemical interactions between silver and the organic matrix and n-doping of CuPcF$_4$ at the initial stages of silver deposition, which is associated with charge transfer from the 2D wetting layer on the basis of core-level spectra shift analysis., Published by ACS Publications, Washington, DC

Hybrid structures composed of graphene films and (0001) graphene ribbons perpendicular to the surface of a graphene-like film have been produced through the catalytic decomposition of a carbon-containing gas on an Al-coated SiO2/Si substrate having Ni catalyst islands on its surface. A hybrid structure has been grown by a one-step chemical vapor deposition process, by admitting acetylene into a chamber for a short time. The hybrid structures thus produced have been used to fabricate Hall sensors with a sensitivity of 3000 Ω/T. The synthesized hybrid structures are potential candidates for use in nanoelectronic devices, energy storage systems, etc. The technique proposed for the growth of such films is compatible with technologies that are employed in the electronics industry.

This paper deals with a study of the thermal effects exhibited when heating samples of composites which comprise aluminium and copper matrices and nanodiamond reinforcing particles. Composites were produced by mechanical alloying in planetary mill. Composites with a nanodiamond content from 10 to 25 vol% were prepared for the study. Initial nanodiamond agglomerates were broken after mechanical alloying. DSC study showed that the reaction between nanodiamond particles and the aluminium matrix starts at considerably lower temperatures compared to macro-objects. But up to 400 – 450 °C, there are no limits in using such composites.

Magnetically modulated PrDyFeCoB microwires containing periodical local magnetic labels of ~ 10 μm length are imprinted by single 120 ns laser impulse. Initially amorphous microwires is locally transformed by laser irradiation to nanocrystalline (PrDy)2(FeCo)14B1, and (PrDy)1(FeCo)2, (PrDy)1(FeCo)4B1 magnetic phases, possessing enhanced magnetic anisotropy. Alternating magnetic patterns imprinted by laser irradiation have magnetization component perpendicular to the microwire main axis. Fast imprinting of the magnetic microlabels allows one to design programmable microstructures.

The nanostructural and tribological characteristics of carbon nanocomposite coatings (CNCs), deposited by accelerated C60 ions at high temperatures, were studied. The CNCs were successfully fabricated on Ti-alloy using a flux that contained C60 ions with 5 and 10 keV energies. Unlike the previous studies, ion mass-separator was not implemented to the deposition process. This enabled deposition of sp2-rich CNCs with a lower coefficient of friction (COF) at a higher deposition rate. Laser confocal microscopy, atomic force microscopy transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and X-ray Auger Electron Spectroscopy were used to investigate the structure of the coatings and friction test results. A carbon nanocomposite film consisting of graphite nanocrystals enclosed in an amorphous diamond-like matrix was formed at a deposition temperature of 300–400 °C. Upon deposition of the CNC, a COF of ~0.06 was achieved, which was almost one order of magnitude lower than that of bare Ti-alloy substrate. The surface wear was reduced by 360 times. The wear mechanism was changed from abrasive wear (on bare Ti-alloy) to a burnishing smoothening of the surface roughness (on CNCs). The transfer of graphite nanocrystals from the coating to the counter surface was identified and observed to act as a solid lubricant.

Plasmonic nanoresonators consisting of a gold nanorod and a spherical silica core and gold shell, both coated with a gain layer, were optimized to maximize the stimulated emission in the near-field (NF-c-type) and the outcoupling into the far-field (FF-c-type) and to enter into the spasing operation region (NF-c*-type). It was shown that in the case of a moderate dye concentration, the nanorod has more advantages: smaller lasing threshold and larger slope efficiency and larger achieved intensities in the near-field in addition to FF-c-type systems’ smaller gain and outflow threshold, earlier dip-to-peak switching in the spectrum and slightly larger far-field outcoupling efficiency. However, the near-field (far-field) bandwidth is smaller for NF-c-type (FF-c-type) core–shell nanoresonators. In the case of a larger dye concentration (NF-c*-type), although the slope efficiency and near-field intensity remain larger for the nanorod, the core–shell nanoresonator is more advantageous, considering the smaller lasing, outflow, absorption and extinction cross-section thresholds and near-field bandwidth as well as the significantly larger internal and external quantum efficiencies. It was also shown that the strong-coupling of time-competing plasmonic modes accompanies the transition from lasing to spasing occurring, when the extinction cross-section crosses zero. As a result of the most efficient enhancement in the forward direction, the most uniform far-field distribution was achieved.

A new carbon material (NCM-R) was studied, which has a number of unique properties: a high specific surface area according to the BET (SBET = 3270 m2/g), a high micropore volume (~1.7 cm3/g), and a very high specific capacity of 870 F/g. The NCM-R is obtained by carbonizing a mixture of dextrin and graphene oxide and activating the carbonizate with potassium hydroxide. Based on the charging and discharge characteristics, it was established that the NCM-R is a promising material for supercapacitor electrodes with very small (diapason of a few seconds) discharge times and anodes of asymmetric supercapacitors with high specific energy. It is assumed that a large specific capacity is due to the reversible chemical attachment of hydrogen atoms to the carbon skeleton when the NCM-R charge is in the cathode region of the potentials.

Regularities of the formation of silver nanoparticles according to the reduction reaction of silver oligostyrylmonocarboxylate with ED-20 resin in the absence of hardening agent were studied at 60–75°C by UV/Vis spectroscopy and IR spectroscopy, transmission electron microscopy, and viscosimetry. Spherical silver nanoparticles with oligostyrylcarboxylate ligands characterized by diameter equal to 1.8 ± 0.2 nm and tendency toward ordered disposition in space were obtained. The process of formation of nanoparticles includes consecutive formation of diphilic complexes of silver carboxylate with epoxy resin, Ag+ → Ag0 reduction, and formation of (Ag0) n nuclei at the ends of the diexpoxy component and/or along the oligomer chain. The activation energy values of formation of nanoparticles during the “inductive period” and at the stage of accumulation as well as the activation energy of viscous flow of ED-20 were measured. The threshold temperature of formation of narrow-size silver nanoparticles in epoxy oligomer ED-20 equals 75°C.

As in the case of metals, laser ablation of germanium and silicon in superfluid helium leads to the formation of thin nanowires; spherical nanoclusters are also present in ablation products. A decrease in the resistance of bundles of silicon nanowires with increasing temperature is typical of semiconductors. Laser ablation of amorphous graphite also leads to the formation of quasi-one-dimensional structures, but there are no spherical clusters among the coagulation products. The structure of carbon filaments is amorphous; they contain onion-like entities, and nanodiamonds appear as coagulation products when the concentration of carbon introduced into superfluid helium increases. The peculiar behavior of carbon is associated with the impossibility of its melting at low pressures.

Method of in situ synthesis of TiC nanoparticles inside aluminium matrix directly during mechanical alloying from aluminium, titanium and nanodiamonds is developed. For this method, nanodiamonds were used as carbon material and as intensificator of mechanosynthesis during the ball milling. Optimal content of matrix material was determined. If the amount of aluminium falls below the optimal level, the synthesis becomes extremely intensified; it means that during short period a large amount of heat is released, which causes substantial grinding jars heating and frequently results in melting of sealing gaskets and other process failures. In case the amount of aluminium in the mixture grows beyond the optimal level, the synthesis process is slowed down. Optimal composition for obtaining TiC nanoparticles inside aluminium matrix is following: 43%wt Al + 57%wt TiC. Average size of nanoreinforcements of developed composite equals 31 nm. Developed material can be applied in casting technologies as an individual product and as a master alloy.

A mobile measuring cell was proposed and created using a focused ion beam as a nanoknife for measuring the electrical characteristics of individual nanowires and nanotubes by the four-wire method. The cell consists of two elements: the basic one, on whose surface a nanoconductor is deposited, and the auxiliary element that provides the electrical connection of the primary element to the wires of the external measuring circuit. Micro- and nanoscale wires in both elements of the cell were formed from gold films deposited on a silicon oxide surface. This provides reliable contacts between a nanoobject and the wires. In this paper, the application of the proposed method was demonstrated using examples of a multiwalled carbon nanotube and a thin platinum nanowire. The electrical resistance of the nanotube was measured using the two-wire method, whereas the current–voltage characteristic for the platinum nanowire was measured via the fourwire method.

We synthesized C8 nanocrystals (NCs) by carbonization and deposition of anthracene vapors onto various substrates. C8 nanocrystals have a bcc lattice with cell parameter a = (4.08 ± 0.02) A. A hypothesis is proposed on the possibility of C8 NC formation in the vapor phase and was confirmed in the experiment.

In this work, we synthesized C8 cubic carbon microcrystals by carbonization of anthracene. Gas products of carbonization were trapped at the outlet of the pipe in distilled water. By the methods of SEM, HRTEM and electron diffraction the morphology and structure of the obtained nanocrystals were studied. It is shown that carbonization of anthracene vapors leads to the formation of plate-like C8 crystals of up to 0.5 microns in size. The unit cell parameter within the bcc lattice is a = 4.08 (0.02) A.In this work, we synthesized C8 cubic carbon microcrystals by carbonization of anthracene. Gas products of carbonization were trapped at the outlet of the pipe in distilled water. By the methods of SEM, HRTEM and electron diffraction the morphology and structure of the obtained nanocrystals were studied. It is shown that carbonization of anthracene vapors leads to the formation of plate-like C8 crystals of up to 0.5 microns in size. The unit cell parameter within the bcc lattice is a = 4.08 (0.02) A.

We study the in-situ growth of a nanocomposite material consisting of a thin CuPcF4 film and multiphase/multidimensional indium nanoparticles, self-organizing on the surface and in the bulk, at various stages of thermal deposition of metal on an organic film under ultrahigh vacuum conditions. The analysis of high-resolution transmission electron microscopy (HR-TEM) images provided valuable information about the evolution of morphology, size, density, and distribution of indium nanoparticles upon indium deposition. These 2D/3D ultra-small nano-objects turned out to have not only body-centered tetragonal (bct) crystal structure, typical for bulk indium, but also unusual face-centered cubic (fcc) one. Using a synchrotron facility, the study of the electronic structure of the hybrid nanocomposite on variable stages of metal deposition was performed by XPS and NEXAFS. Core-level spectra related to the organics indicated reasonably weak chemical interaction of indium with CuPcF4 molecules, which is not the case for a number of metal/organic semiconductor systems, while valence band spectra have shown a considerable change of the material electronic properties. The energy level diagrams, derived from the experiment, can be applied for the creation of new prototypes of metal-organic memory devices.

Nanostructured powders of terbium oxides were prepared by the thermal decomposition of terbium acetate at different temperatures. The powders were investigated by means of XRD, HRTEM, magnetic measurements, and IR spectroscopy. It has been found that the most likely composition of the oxides is Tb4O7, and the powders containing more than one crystalline phase. At low temperatures the prepared oxides exhibit antiferromagnetic ordering with the Weiss constants ranging from −14 to −22 K. At 2 K the effective value of total angular momentum per one Tb ion in the paramagnetic state J = 2.5 ± 0.1. The effects of the calcination temperature on the crystal structure, microstructure and magnetic behaviors of the samples are discussed in terms of that surface impurities presented in the nanocrystalline powders of Tb oxides influence the cation Tb4+/Tb3+ ratio in their crystal lattice.

Carbon films were fabricated on oxidized silicon substrates coated by treated bi-layer catalyst film using a chemical vapor deposition (CVD) method with a short-time acetylene inflow. The films consisted of carbon nanotubes and bundles of them, and graphene-like carbon nanostructures. Unusually high magnetic field sensitivity (3000 Ω/T) obtained from Hall measurements was observed in the films. The effect of scaling the size of the Hall sensor from carbon films on its magnetic field sensitivity has been investigated. The sensitivity of the Hall sensor with an active area size of 0.13×0.13 µm2 was found to be 1140 Ω/T, which is much higher than reported in the literature. This carbon material is promising for the fabrication of Hall effect sensors of submicron size.

The purpose of this work is the synthesis and study of the properties of nanocomposite structures created by noble metal (silver) nanoparticles (NP's), an exciting class of materials with unique properties differ from both bulk and atomic behavior, which are self-organize in a thin organic film of copper phthalocyanine (CuPc). The structure and morphology of this material, depending on the amount of deposited silver, was studied in ultrahigh vacuum using transmission electron microscopy (TEM) and photoelectron spectroscopy (PES). Metallic atoms deposited on the surface of an organic substrate diffuse into the substrate, forming NPs with a narrow size distribution, which correlates with the content of the deposited metal. With the help of high-resolution TEM, the distance between the atomic planes of individual silver nanoparticles was determined and the steady gathering of individual nanoparticles into agglomerates and then into nanocrystals with inter-crystallite boundaries was observed. PES revealed a generally weak interaction between silver NPs and the organic matrix. However, a strong band bending in the organic film at small coatings with metal atoms was observed.

Nanowires of niobium, platinum and indium–lead In88Pb12 alloy with diameters of 4.2, 3.6 and 8 nm, respectively, were grown in quantized vortices of superfluid helium, and the dependences of their resistance on temperature have been studied. Through a detailed comparison of these dependences we present evidence that superconducting niobium wires allow a high rate of quantum phase slip. This phase slippage leads to a phase transition to an insulating state at T → 0.

This study investigates the scheme “mechanical alloying for obtaining a uniform distribution of non-agglomerated nanodiamonds inside a copper matrix + compaction of mechanically alloyed granules into a bulk material in the shape of an anode + electroplating the composite coating by transferring the composite material from the dissolved anode to the cathode, which is the material to be treated”. It is shown that mechanical alloying can be an effective method for producing metal matrix composites with non-agglomerated reinforcing nanodiamond particles. The production of electrochemical coatings from particulate copper matrix composites with non-agglomerated nanodiamond reinforcements is developed. The absence of nanodiamond agglomerates increases the quality of the coating and reduces the risk of its breakdown.

Thin (D10 nm) nanowires are in principle promising for their application as catalysts and as elements of nanocomputers and quantum devices. To perform these tasks, their structure and properties must be stable at least at standard conditions. Using our technique based on the capture of small particles to the core of quantized vortices in superfluid helium, we synthesized nanowires made of various metals and alloys and investigated their thermal stability. The indium nanowires (D = 8 nm) were shown to be stable when heated to 100 °C, i.e., almost to the melting point, whereas the silver nanowires (D = 5 nm) disintegrated into traces of individual nanoclusters at 300 K. The gold and platinum nanowires also decomposed at temperatures more than twice as low as the melting point. A model is proposed to explain the premature decay of thin nanowires by unfreezing of the surface-atom mobility in combination with the anomalous dependence of the surface tension on the nanowire radius. Methods for improving the stability limits of thin nanowires by saturation of their surface with immobilized atoms as well as by surface oxidation have been proposed and experimentally tested.

The composition and structure of the boundary between superconducting and stabilizing layers in a taped high-temperature superconductor of the second generation are studied by means of scanning and transmission electron microscopy. The superconducting and stabilizing layers are fabricated on the basis of a GdBa2Cu3O y oxide layer and metallic silver, respectively. It is shown that nanosized pores 15–30 nm in diameter are located on the boundary from the side of silver layer. The presence of these pores likely determines the magnitude of the interface resistance between the superconducting and stabilizing layers.

In this work, we report results of a study of bismuth nanowires growth on various substrates, including Fe, Ni, Co, W, Pt, Au thin films on oxidized Si, Si (111), oxidized Si (100), and fused quartz. The nanowires (NW) were prepared by RF diode sputtering of Bi onto a substrate heated to about 200 °C. The structure of the wires was studied by a scanning and transmission electron microscopy. The NWs are monocrystalline up to a length of several micrometers and possess a very thin (less than 2 nm) oxide layer. A major influence of the substrate type on the quantity and the length of the obtained nanowires is observed. Based on the above studies, we propose a possible mechanism of a bismuth nanowire growth.

The structures of graphene layer-carbon nanotube hybrid films produced via CVD with a single-stage flow of acetylene into a chamber containing a prepared substrate are studied. It is shown that such films have a hybrid double-layer structure consisting of a graphene layer and a dense continuous network of nanotubes. The graphene layer contains continuous extended areas 10–50 μm in size and island areas ∼0.1 μm in size. TEM images lead to the conclusion that the graphene layer and carbon nanotubes are bound by covalent bonds.

The architecture of novel metallic mesostructures obtained via self-organization of growing nanowires has been investigated. Seashell, fungus and lotus leafshaped structures are reproducibly formed by programmable pulse current electrodeposition on porous membranes. The samples several millimeters in size are obtained. SEM investigation has revealed that the frame of the metallic seashell presents a hierarchical system with elements of fractal selfsimilarity at the nano- and microlevels. The frame is a volumetric multilayer net with conical bundles of nanowires as building blocks. The Pd-Ni nanowires have V-like branches and periodic bulges . TEM study showed that the nanowires consist of nanocrystallites dispersed in an amorphous matrix. Their sizes range from 4 to 15 nm. Local inhomogeneity of PdNi solid solution was observed. In perspective, the proposed technique can be used as a 3D printer for the purposeful synthesis of novel materials with complex quantum nano-architecture., Comment: 11 pages, 9 figures

Powders of nanostructured holmium oxide (C-Ho2O3) with the crystallite sizes ranging from 6 to 16 nm have been prepared in bulk from the thermal decomposition of holmium acetate and carbamide-containing complex of holmium as precursors at 600 and 700 °C. The powders obtained have been investigated by X-ray diffraction, TEM, thermogravimetry, IR- and Raman spectroscopy. A comparison has been drawn between these and powdered holmium oxide with micron-sized crystallites prepared from the thermal decomposition of holmium chloride. The bcc lattice parameter of the oxides has been found to increase when the crystallite size decreases. It has been noted that the surface of air-exposed powders of holmium oxides is covered by products formed due to the chemisorption of atmospheric CO2 and H2O molecules.

We have measured the electrical conductivity of lanthanum oxide based composite materials containing different concentrations of carbon nanofibers as additives. The conductivity has been shown to increase sharply (by two orders of magnitude) at carbon nanofiber contents from 2 to 3 wt % owing to the formation of a three-dimensional network of nanofibers in the bulk of the composite. Particular attention has been paid to the morphology of the particles of the constituent components of the composites and to the chemical and phase compositions of the matrix material.

It has been shown that micrometer-sized balls, resulting from the condensation of products of laser ablation of fusible metals in both superfluid helium and water, are in the state of strong internal tension counterbalanced by external compression. By radiation-induced or chemical damage to the integrity of their surface, they break up, ejecting a plurality of nanoparticles. The empty shells of the microspheres, which nonetheless remain intact, are identical to the “hollow spheres” of unclear origin that have been observed previously under laser ablation in usual liquids. The metastability of the microparticles produced by ablation in a liquid should be taken into consideration in their use in engineering and medicine.

2D conjugated polyphthalocyanines can be obtained as two distinctly different types of material with specific molecular structures and different morphological properties. It was believed that the temperature is the key factor affecting the chemical reaction, but we show that even at the optimal temperature (420 °C), the reaction on vapor/solid interface and liquid/solid interface yields different products: while the former is well-polymerized and ordered, the latter is amorphous and cross-linked with the typical conjugation scale of single phthalocyanine (PC) ring. Infrared spectroscopy is most sensitive tool for identifying the molecular structure, providing the information on polymerization degree, structural uniformity and content of terminal groups. We show that, unlike the ordered polyphthalocyanines, the cross-linked product can be reproducibly obtained as continuous conductive material.

The severe plastic deformation strongly changes the microstructure and properties of titanium-based alloys. The structure and microhardness of four binary and ternary titanium-based alloys (Ti–4 wt. % V, Ti–4 wt. % V–6 wt. % Al, Ti–4 wt. % V–3 wt. % Al, and Ti–5 wt. % V–6 wt. % Al) have been studied after preliminary annealing and following high pressure torsion (HPT). After HPT, the Ti–4 wt. % V alloy contains much less (ωTi) phase than Ti–4 wt. % Fe and Ti–4 wt. % Co alloys. The addition of aluminum to the binary Ti–V alloys completely suppresses the formation of the high-pressure (ωTi)-phase. HPT leads to the partial decomposition of the annealed (αTi) solid solution and “purification” of α-phase similar to that in the Ti–Fe alloys. After HPT of the studied ternary alloys, the (βTi)-phase completely disappears and nanoparticles of Ti2Fe form instead. This fact explains why the addition of aluminum leads to the increase of microhardness of alloys after annealing between 600 °C and 950 °C and after HPT-treatment. The increase of the temperature of the preliminary annealing also increases the hardness of all alloys after HPT-treatment.

The microstructures of Pt/C and PtM/C (M = Ni, Cu, or Ag) electrocatalysts were studied using X-ray diffraction and transmission electron microscopy (TEM). The electrochemically active surface areas of the prepared materials were estimated by cyclic voltammetry in 1 M H2SO4. The materials, with metal contents ranging from 30 to 35 wt.%, were synthesized by chemically reducing the metal precursors in water–ethylene glycol solutions. The actual composition of the bimetallic nanoparticles corresponds to a theoretical (1:1) composition for the PtAg/C catalysts, whereas in the PtNi/C and PtCu/C materials, a portion of the alloying component exists in an oxide form. Decreasing the average metallic crystallite sizes from 3.5 to 1.6 nm does not increase the electrochemically active surface area. This apparent contradiction is because a majority of the PtNi and PtCu nanoparticles consist of 2–4 disordered crystallites. In addition, a portion of the PtNi or PtCu nanoparticle surface is covered by nickel or copper oxides, respectively. PtAg nanoparticles, which have a smaller size relative to other bimetallic particles according to the TEM data, are characterized by an intense platinum surface segregation. The agglomeration processes are lowest for the PtAg nanoparticles.

Synthesis, morphology, and structural characteristics of carbon and SiC/C nanocomposites with a lattice of inverse opal were investigated. Porous structure characteristics were determined by gas adsorption-desorption. Photoluminescence of SiC/C nanocomposites, induced by implantation of helium ions, and their structure revealed by high-resolution transmission electron microscopy were studied.