Formation of Planar Field-Emission Devices Based on Carbon Nanotubes on Co–Nb–N–(O) Alloy

Semiconductors - Integrated field-emission devices and integrated circuits (ICs) based on them are a promising direction in microelectronics, which is associated with the use of low-voltage and...     

Formation of carbon nanotubes on an amorphous Ni<Subscript>25</Subscript>Ta<Subscript>58</Subscript>N<Subscript>17</Subscript> alloy film by chemical vapor deposition

It is shown that it is possible to grow carbon nanotubes on the surface of an amorphous Ni–Ta–N metal alloy film with a low Ni content (~25 at %) by chemical deposition from acetylene at temperature 400–800°C. It is established that the addition of nitrogen into the Ni–Ta alloy composition is favorable for the formation of tantalum nitride and the expulsion of Ni clusters, which act as a catalyst of the growth of carbon nanotubes, onto the surface. From Raman spectroscopy studies, it is found that, as the temperature of synthesis is raised, the quality of nanotubes is improved.     

Interaction between thin indium films and single-crystal ZnAs2 substrates

X-ray photoelectron and Auger electron spectroscopic studies of In/ZnAs₂ structures revealed a chemical reaction at the film-substrate interface at substrate temperatures between 400 and 650 K. Gibbs energy calculations showed that the more likely products of the interfacial reaction are InAs and Zn₃As₂.     

The diffusion coefficient of Brownian particles in a rapidly fluctuating periodic potential field

An exact formula describing the effective coefficient of diffusion for Brownian particles in a rapidly fluctuating periodic potential field is derived. It is shown that, irrespective of the particular form of the potential, the particle migration is accelerated as compared to the case of free diffusion. The values of diffusion coefficients for several particular potential profiles are calculated.     

Specific features of the structure and properties of carbon nanocolumns formed by low-temperature chemical vapor deposition

The process of the formation of column-shaped carbon nanostructures by plasma-enhanced chemical vapor deposition is explored. Carbon nanocolumns are formed at 250°C. The structure and properties of the structures are studied by atomic-force microscopy, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The electrical properties of the structures are investigated.     

Growth of carbon nanotube arrays on various CtxMey alloy films by chemical vapour deposition method

Carbon nanotube(CNT) arrays were fabricated on Ct-Me-N-(O) alloys with content of Ct in the range of 6–40 at.% by chemical vapour deposition. The Ct was a catalytic metal from the group of the following elements: Ni, Co, Fe, Pd, while Me was a transition metal from the group of Ⅳ–Ⅶ of the periodic table(where Me = Ti, V, Cr, Zr, Nb, Mo, Ta, W, Re). Carbon nanotubes were found to grow efficiently on the alloy surface with its composition containing Ti, V, Cr, Zr, Hf, Nb or Ta. The growth of CNTs was not observed when the alloy contained W or Re. Additions of oxygen and nitrogen in the alloy facilitated the formation of oxynitrides and catalyst extrusion on the alloy surface. Replacement of the metals in alloy composition affected the diameter of the resulting CNTs. The obtained results showed that the alloy films of varying thickness(10–500 nm) may be used for the CNTs growth. The resulting CNT material was highly homogenous and its synthesis reproducible.     

Modification of the organic matter of brown coals with nitrous oxide

The results of the treatment of brown coals from the Kansk-Achinsk Basin in an atmosphere of nitrous oxide are given. It was established that the main products of nitrous oxide interaction with the organic matter of brown coal are soluble low-molecular-weight products (ketones and aromatic acids) and oxodiazoline structures in a coal matrix. The thermal-oxidative degradation of terminal oxygen-containing groups, which accompanied this process, facilitated the formation of strong crosslinks and the strengthening of a supramolecular structure.     

A pulse high-frequency power supply system for hyperbolic mass analyzers of space vehicles

A pulse oscillator for powering dynamic mass spectrometers with a frequency mass-spectrum scan is described. The used resonance method of forming leading edges of pulses allowed one to reduce the power consumption by a factor of 4–6 as compared to the simple charge exchange of the load capacitance. Efficient oscillators with a 4-MHz maximal pulse repetition rate, a 100-V peak-to-peak output voltage, and 1-W consumed power are designed.     

Scrap tyre rubber depolymerization by nitrous oxide: products and mechanism of reaction

The development of effective methods for reclaiming scrap tyre rubbers attracts a great deal of attention. Earlier, we have proposed an alternative way for reclaiming waste rubber, which consists in its treatment with nitrous oxide (N₂O) at 180–230 °C and pressure of 2–5 MPa. In the present study, the reclaimed products obtained by this method from tyre crumb rubber were characterized for the first time by TGA, FTIR, NMR, and ultimate analysis techniques. The results showed that the sol fraction isolated from the reclaimed rubber consists mainly of diene oligomers with the carbonyl, predominantly ketone, groups. The remaining gel fraction includes some of the rubber polymer components and all the carbon black filler present in the initial vulcanizate. Based on the experimental results, a mechanism of vulcanized rubber interaction with nitrous oxide was suggested. The mechanism involves a selective 1,3-dipolar cycloaddition of N₂O molecules to C=C bonds of isoprene and butadiene units in vulcanized elastomers. The main reaction route proceeds without cleavage of initial C=C bonds leading to the formation of ketone groups randomly distributed along the polymer backbone. The cleavage of a certain amount of reacting C=C bonds leads to controllable scission of macromolecular chains and accordingly to depolymerization of the initial vulcanized rubber, thus yielding a plastic reclaim product. The sulfur cross-links do not appear to be broken in the course of waste rubber treatment.