Spray-deposited carboxylated carbon nanotube (CNT) layers were characterized using AFM, Raman, and spectroscopic ellipsometry. The layers' thickness, diameters and band gap of CNTs, as well as the changes in the CNT layer refractive index at 1319 nm and 2010 nm after H2O and NH3 adsorption in air and H2O in N-2 were analyzed. Refractive index changes and modeling the necessary length of the modified interferometer arm for a pi/2 phase shift allow us to propose the use of such CNT layers for integrated interferometric sensors and gas recognition.

A promising material for cold cathodes creation are carbon films with both acceptable emission properties and satisfactory adhesion to the substrate. It is known that inclusions of metallic elements (chromium, titanium, etc.) improve the adhesion of the carbon film to the substrate. One of the methods for producing coatings based on carbon and titanium is electric arc spraying of a Ti/C composite cathode in an argon atmosphere. The disadvantage of this method is the presence in the total plasma flow of carbon microparticles, which are sources of structural defects in the growing film. Magnetic separation of carbon plasma solves the above problem. In this work, composite metal-carbon films were obtained by simultaneous electric arc spraying of graphite in a magnetic field and of titanium from two evaporators. The composition of the films was studied by Raman spectroscopy (RS) and X-ray photoelectron spectroscopy (XPS). It has been established that the samples obtained are composite films consisting of graphite nanoparticles, Ti14C13 nanoclusters or Ti8C12, titanium oxides, and titanium carbide TiCxN1–x compounds.

Graphene transfer using polymers as a supporting layer makes sensors with exceptional yield and few defects. It is still an issue to make scalable and versatile high-purity graphene transfer method. Current-voltage characteristic slope and hence the sensitivity of the graphenebased devices are limited by the residual polymer left after the transfer process that forms local defects and trapped states quenching charge transfer. Due to the strong interactions between polymer and graphene, residual removal remains an important problem to solve. In this work graphene on Cu foil was covered using spin-coating of poly(methyl methacrylate) (PMMA) with different molecular masses and the addition of a low volatile additive. The film obtained was transferred onto Si/SiO2 substrates. In order to remove PMMA residues multiple cleaning techniques with different solvents were used and compared to each other; new methods were developed. The quality of the purified graphene was studied by analyzing AFM, Raman, fluorescence spectroscopy data. The structure was <1 nm thick with a 2D to G peak ratio, of similar to 5.

After graphene transfer, solvent mixtures were used to remove residual PMMA, which efficiency was estimated by AFM, Raman spectroscopy, and CVC. That post-treatment gives: stress relaxation (2D peak shift, compared to trichloroethylene), 2D/G intensity ratio 1.1 changes to 2.6, clean graphene regions exceed 100-150 nm size; threshold point shifts to zero but the conductivity and mobility reduce. Ethanolamine functionalizes both PMMA and graphene.

A carbon nanotubes (CNT) network is a promising gas sensing material for "e-nose" development due to the vast methods of cross-sensitivity modification. However, the dominant sensitivity mechanism remains unclear since both the CNTs and junctions between CNTs can be gas-sensitive. In this paper to estimate the contributions of both mechanisms, we simulated CNT networks with varied densities using an equivalent electrical circuit. Density variation alters the junction's and CNT's contribution to the network resistance, and hence the total resistive response. We compared the results with the experimental resistive response of the spray-coated CNT networks toward ammonia (NH3). A decrease in the network density results in a higher response, which indicates a likely significant role of CNTs junctions in sensitivity of a sparse networks. We also studied the effect of formic acid treatment on CNT networks, which increases both conductivity and sensitivity by removing residual solvent.

In this article a new approach to graphene oxide spray deposition is demonstrated. Developed spray methodic allows to fabricate uniform low thickness graphene oxide coatings on a wide range of substrates without surface hydrophilization. A comparison of films obtained by spray a spin coating methods is given. The perspectives of industrial application of developed method for production of graphene oxide bio- and gas sensors are considered. Results of graphene oxide films local reduction performed by 1030 nm continuous CO2 laser engraver and 445 nm solid-state laser are presented. Features and difficulties of thin graphene oxide films reduction are discussed.

The process of oxidation of single-layer and multilayer graphene films upon ultraviolet irradiation of the structure in water vapor was studied. The systematic features and distinctions between changes in the topographic and optical properties of graphene films composed of different numbers of layers were established. The possibility of surface functionalization accompanied by modification of the energy structure of graphene was shown. Differences between single-layer and multilayer graphene films in the mechanisms of oxidation on ultraviolet irradiation are discussed and analyzed. Correlation of the topographic imperfections of the properties of the graphene material with its structural defects observed in Raman spectra was shown.

We investigate the effect of UV processing of graphene with different structural properties prepared by mechanical exfoliation and CVD growth. Depending on UV exposure time, we observe different effects like oxidation, doping, and etching. For bi-layered and few-layered graphene flakes, we do not observe significant etching even after 3 h exposure which indicates the high resistance of graphene to reactive oxygen species intercalation between graphene layers. Single-layer CVD-grown graphene is fully etched after 2 h of UV treatment. The crystalline size of exfoliated single layer graphene after UV exposure drops from 45 to 5 nm while for CVD graphene from just 10 to 2 nm. We investigate the effect of UV irradiation on field effect transistors, demonstrating sequential cleaning from polymer residuals, oxidation (doping), and final etching of graphene. After 30 minutes of UV irradiation, we observe the hole mobility of a CVD single layer graphene transistor increasing up to 400 cm2/V·s.

Techniques have been developed for forming integrated graphene structures on a silicon wafer surface by mechanical and chemical splitting and chemical vapor deposition. The imperfection of the fabricated structures has been investigated by atomic force microscopy and X-ray diffraction. For the aerosol technique of deposition of mechanically spit graphite, the regularity has been revealed in the reduction of the graphene sheet size with increasing pressure. The correlation of the topographic defects of graphene material and the structural defects observed in X-ray diffraction patterns is demonstrated.