Simultaneous mass production of high quality vertically oriented graphene nanostructures and doping them by using an inductively coupled plasma chemical vapor deposition (ICP CVD) is a technological problem because little is understood about their growth mechanism over enlarged surfaces. We introduce a new method that combines the ICP CVD with roll-to-roll technology to enable the in-situ preparation of vertically oriented graphene by using propane as a precursor gas and nitrogen or silicon as dopants. This new technology enables preparation of vertically oriented graphene with distinct morphology and composition on a moving copper foil substrate at a lower cost. The technological parameters such as deposition time (1–30 min), gas partial pressure, composition of the gas mixture (propane, argon, nitrogen or silane), heating treatment (1–60 min) and temperature (350–500 °C) were varied to reveal the nanostructure growth, the evolution of its morphology and heteroatom’s intercalation by nitrogen or silicon. Unique nanostructures were examined by FE-SEM microscopy, Raman spectroscopy and energy dispersive X-Ray scattering techniques. The undoped and nitrogen- or silicon-doped nanostructures can be prepared with the full area coverage of the copper substrate on industrially manufactured surface defects. Longer deposition time (30 min, 450 °C) causes carbon amorphization and an increased fraction of sp3-hybridized carbon, leading to enlargement of vertically oriented carbonaceous nanostructures and growth of pillars.

A lack of observable quantities renders it generally difficult to confront models of Space Weather with experimental data and drastically reduces the forecast accuracy. This is especially true for the region of Earth’s atmosphere between altitudes of 90 km and 300 km, which is practically inaccessible, except by means of remote sensing techniques. For this reason auroral emissions are an interesting proxy for the physical processes taking place in this region. This paper describes two future space missions, AMICal Sat and ATISE, that will rely on CubeSats to observe the aurora. These satellites will perform measurements of auroral emissions in order to reconstruct the deposition of particle precipitations in auroral regions. ATISE is a 12U CubeSat with a spectrometer and imager payloads. The spectrometer is built using the micro-Spectrometer-On-a-Chip (μSPOC) technology. It will work in the 370–900 nm wavelength range and allow for short exposure times of around 1 s. The spectrometer will have six lines of sight. The joint imager is a miniaturized wide-field imager based on the Teledyne-E2V ONYX detector in combination with a large aperture objective. Observation will be done at the limb and will enable reconstruction of the vertical profile of the auroral emissions. ATISE is planned to be launched in mid 2021. AMICal Sat is a 2U CubeSat that will embed the imager of ATISE and will observe the aurora both in limb and nadir configurations. This imager will enable measuring vertical profiles of the emission when observing in a limb configuration similar to that of ATISE. It will map a large part of the night side auroral oval with a resolution of the order of a few km. Both the spectrometer and imager will be calibrated with a photometric precision better than 10% using the moon as a wide-field, stable and extended source. Ground-based demonstrators of both instruments have been tested in 2017 in Norway and Svalbard. Even though some issues still need to be solved, the first results are very encouraging for the planned future space missions. Data interpretation will be done using the forward Transsolo code, a 1D kinetic code solving the Boltzmann equation along a local vertical and enabling simulation of the thermospheric and ionospheric emissions using precipitation data as input.

Features of the reduction of graphene from graphene oxide in media containing hydrazine hydrate, ethylene glycol, and hydrogen are studied. X-ray energy dispersive spectroscopy, Raman spectroscopy, and scanning electron microscopy data indicate that this process proceeds through the high-temperature annealing of graphene oxide in a hydrogen environment.

The interaction of electromagnetic radiation with a magnetically functionalized nanocomposite based on carbon nanotubes (CNTs) is considered using the model of random distribution of ferromagnetic nanoparticles in the carbon matrix characterized by the presence of resistive–inductive–capacitive coupling (contours). The model is based on the representation of the nanocomposite as a system consisting of the CNT matrix, ferromagnetic nanoparticles, and the interfaces between CNTs and nanoparticles. The wide range of possible resonant phenomena caused both by the presence of contours and the properties of the CNT nanocomposite is shown.

In this article we present the results of micro-Raman studies of graphene grown on copper foil surface by atmospheric pressure CVD using decane as precursor, nitrogen as carrier gas with zero flow of hydrogen. Analysis of Raman spectroscopy data showed that film contains spots with single layer thick graphene. We observed significant blue shift of 2D and G bands positions for mono-atomically thick graphene on copper foil. Following literature we relate this shift to the strain induced by the presence of copper substrate. Moreover, we observed changes in the defectiveness of graphene layers after the transfer, which was related to the appearance of chemically-induced defects and defects induced by changes in the mechanical strain.

The effect of oxidation of a nickel catalyst on the growth of carbon nanotubes is experimentally and theoretically analyzed. An expression for the solubility of impurity in the cluster is derived with allowance for the surface tension. It is demonstrated that the oxidation of the surface of the catalyst cluster causes a decrease in the effective coefficient of surface tension. This circumstance leads to an increase in the solubility of carbon in the cluster and an increase in the growth rate of carbon nanotubes.

The hybrid carbon nanostructures composed of an array of vertically aligned carbon nanotubes (CNTs) and a self-organized planar graphite layer (PGL) located on the top of the array (CNT-PGL nanostructures) have been obtained by the CVD method with the volatile catalyst. The fundamental characteristics (morphology, elemental composition and structure) of these nanostructures were characterized by Scanning and Transmission Electron Microscopy, Energy-dispersive X-ray (EDX), Raman and Auger spectroscopy. It has established that CNTs grow simultaneously both via root-growth mechanism (attached to the substrate) and tip-growth mechanism (attached to the planar layer). This planar layer is a layered - graphitic structure and connected with CNTs through the catalyst nanoparticles. It consists of disordered graphite flakes with the sizes of some tens of nanometers randomly oriented and overlapping with one another. These graphitic flakes have a crystallite of ~5.2 nm in size.

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/cm(2) in the longitudinal direction of CNTs. Scanning electron microscopy (SEM) indicated changes of the top (similar to 3 mu m) 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.

A method for calculating the field-emission current from a single carbon nanotube in an external electric field directed along the nanotube is presented. The method is based on a semiclassical approach using the subbarrier-tunneling mechanism. It is shown that the current corresponds to the Nordheim-Fowler mechanism for field emission in the case of strong fields; in the case of weak fields, there are deviations associated with features of the behavior of the potential barrier.

Femtosecond lasers (FSL) are playing an increasingly important role in materials research, characterization, and modification. Due to an extremely short pulse width, interactions of FSL irradiation with solid surfaces attract special interest, and a number of unusual phenomena resulted in the formation of new materials are expected. Here, we report on a new nanostructure observed after the interaction of FSL irradiation with arrays of vertically aligned carbon nanotubes (CNTs) intercalated with iron phase catalyst nanoparticles. It was revealed that the FSL laser ablation transforms the topmost layer of CNT array into iron phase nanospheres (40 to 680 nm in diameter) located at the tip of the CNT bundles of conical shape. Besides, the smaller nanospheres (10 to 30 nm in diameter) are found to be beaded at the sides of these bundles. Some of the larger nanospheres are encapsulated into carbon shells, which sometime are found to contain CNTs. The mechanism of creation of such nanostructures is proposed.

The results of development and studies of humidity-sensitive elements based on a carbon-nanotube bundle are presented. It has been demonstrated that arrays of nanotubes grown by the low-temperature plasma-chemical method on planar silicon structures have exceptional sensitivity to humidity. The ratio of the structure resistance in dry and humid states is more than 10(5)-fold. Such a high relative resistance change is caused by the character of changes in conductivity of the charge carriers between individual tubes of the bundle upon adsorption of water molecules.

This paper reports the results of a comprehensive study of the interaction of electromagnetic radiation (EMR) of the wide frequency range (8-12, 26-37, and 78-118 GHz) with arrays of vertically aligned and disordered carbon nanotubes (CNTs) which have been obtained by the floating catalyst chemical vapor deposition method. The obtained nanotubes represent a composite of multiwall CNTs with encapsulated magnetic nanoparticles of iron phases, i.e., magnetically functionalized nanotubes (MFCNTs). MFCNTs were formed on silicon substrates, and disordered arrays in the form of powder were obtained by separating the MFCNT arrays mechanically from the walls of the quartz reactor. The frequency dependences of the reflection and transmission coefficients of EMR of MFCNTs of two types were investigated. The high electromagnetic shielding efficiency (40 dB) of MFCNTs associated with the reflection of electromagnetic waves was detected. Possible mechanisms of attenuation of electromagnetic signals by aligned and disordered MFCNTs were discussed.

Research results on the synthesis of carbon nanotube arrays using a combined catalyst are presented. Thanks to optimal synthesis parameters such as temperature, the reagent flow rate, the concentration and type of organometallic compound, and the composition of the catalyst film, a new synthesis method for the arrays of carbon nanotubes (CNTs) of a given topology is developed. The influence of the size effects of topological elements on the characteristics of the CNT arrays is studied. The results of a statistical analysis and research into the CNT morphology by transmission and scanning electron microscopy are shown.

The effect of the ferrocene concentration in a working gas mixture on carbon nanotube (CNT) growth by the CVD method is studied. It is shown that a change in the ferrocene concentration in a gas mixture has a significant effect on CNT growth. A decrease in the ferrocene concentration increases the melt’s free energy and leads to the growth of smaller-diameter nanotubes with a lower number of walls, i.e., two or three. An increase in the ferrocene concentration above 1% leads to degradation of the quality of the growing nanotubes.

Few-wall carbon nanotubes were synthesized by methane/acetylene decomposition over bimetallic Fe-Mo catalyst with MgO (1:8:40) support at the temperature of 900°C. No calcinations and reduction pretreatments were applied to the catalytic powder. The transmission electron microscopy investigation showed that the synthesized carbon nanotubes [CNTs] have high purity and narrow diameter distribution. Raman spectrum showed that the ratio of G to D band line intensities of IG/ID is approximately 10, and the peaks in the low frequency range were attributed to the radial breathing mode corresponding to the nanotubes of small diameters. Thermogravimetric analysis data indicated no amorphous carbon phases. Experiments conducted at higher gas pressures showed the increase of CNT yield up to 83%. Mössbauer spectroscopy, magnetization measurements, X-ray diffraction, high-resolution transmission electron microscopy, and electron diffraction were employed to evaluate the nature of catalyst particles.

Simulation of the excitation of mechanical vibrations in carbon nanotube arrays by ponderomotive forces is presented in continual approximation on the basis of electrodynamics of moving bodies, elasticity theory and van der Waals interactions' theory.

Carbon nanotubes grown on a silicon substrate with an array of FeNiCo20 catalyst islands are studied using focused ion beam and transmission electron microscopy. A method for preparing cross-sectional samples is proposed, which makes it possible to exclude the destructive effect of the ion beam on surface nanostructures during sample preparation using a microscopic three-dimensional protective barrier.