The relationship between sp^2/sp^3 hybridizations ratio of atomic bonds in diamond-like carbon (DLC) and its electrical resistivity for coatings with a thickness in the range 22-70 nm prepared by vacuum arc deposition on silicon substrate of the SHB-8 brand has been established. It is established, that an increase in the coating thickness from 22 to 70 nm is accompanied by a decrease in the specific transverse electrical resistance of samples from 17 to 2 GOhm·m. This effect is explained by an increase in the proportion of carbon atoms with sp^2 hybridization of electronic orbitals from 86 to 91%, which leads to the appearance of an additional number of π-bonds. A mathematical model, describing the spatial distribution of current when measuring transverse I-V characteristic, has been developed. The results obtained will be useful in creating resistive layers on the electrodes of gas-discharge detectors of charged particle to limit the amount of current in the event of rare spark discharges inside them caused by the registration of random highly ionizing particles.

FP9120 diazoquinone–novolac positive photoresist films 1.5 µm thick implanted with Ag+ ions and supported on the surface of KDB-10 (111) silicon wafers by centrifugation have been studied by measuring reflection spectra. It has been shown that ion implantation leads to a decrease in the refractive index of the photoresist due to radiation crosslinking of novolac resin molecules and a decrease in the density ρ and the molecular refraction RM of the photoresist. It has been established that the reflection coefficient in the opaque region of the photoresistive film increases with the Ag+ implantation dose. The changes observed in the optical properties of the films under ion implantation conditions are explained taking into account radiation-chemical processes in the phenol–formaldehyde photoresist.

The thermal, electrical and thermoelectric properties of ZnO– Me x O y ceramics with 1 ≤ x , y ≤ 3, where Me = Al, Co, Fe, Ni, Ti, have been studied. The specimens have been synthesized using the ceramic sintering technology from two or more oxides in an open atmosphere with annealing temperature and time variation. The structural and phase data on the ceramics have shown that post-synthesis addition of Me x O y doping powders to wurtzite-structured ZnO powder causes Zn x ( Mе ) y O 4 spinel-like second phase precipitation and a 4-fold growth of ceramics porosity. Room temperature heat conductivity studies have testified to predominant lattice contribution. A decrease in the heat conductivity upon doping proves to be caused by phonon scattering intensification due to the following factors: size factor upon zinc ion substitution in the ZnO lattice (wurtzite) by Me x O y doping oxide metal ions; defect formation, i.e., point defects, grain boundaries (microstructure refinement); porosity growth (density decline); secondary phase particle nucleation (Zn x ( Mе ) y O 4 spinel-like ones). The above listed factors entailed by zinc ion substitution for metal ions (Co, Al, Ti, Ni, Fe) increase the figure-of-merit ZT by four orders of magnitude (due to a decrease in the electrical resistivity and heat conductivity coupled with a moderate thermo-emf decline). The decrease in the electrical resistivity originates from a more homogeneous distribution of doping metal ions in the wurtzite lattice upon longer annealing which increases the number of donor centers.

The relationship between sp2/sp3 hybridizations ratio of atomic bonds in diamond-like carbon (DLC) and its electrical resistivity for coatings with a thickness in the range 22–70 nm prepared by vacuum arc deposition on silicon substrate of the SHB-8 brand has been established. It is established, that an increase in the coating thickness from 22 to 70 nm is accompanied by a decrease in the specific transverse electrical resistance of samples from 17 to 2 GΩ m. This effect is explained by an increase in the proportion of carbon atoms with sp2 hybridization of electronic orbitals from 86 to 91

The DLC/Kapton structures irradiated with 60 Co γ-rays at doses to 1 MGy have been studied by measuring transmission and attenuated total reflection (ATR) spectra. It has been shown that there are significant changes in the spectra in the ranges of vibrations of О–Н, CH 2 , and CH 3 bonds due to radiation-induced processes in the byproducts of polyimide synthesis and residual solvents. Significant differences were found in the radiation-induced processes occurring in the bulk and near-surface region of a polyimide film and DLC/polyimide structures. After irradiation, the bulk of polyimide exhibited bands due to asymmetric and symmetric vibrations of the CH 3 group. Bands associated with the vibrations of the CH 2 group were additionally observed in the near-surface region. The formation of CH 2 groups in the near-surface layer under irradiation was more pronounced in DLC/polyimide structures than in polyimide films; this was due to the additional supply of hydrogen from the DLC film.

The relationship between the chemical composition, phase structure, grain size, electrical resistance, and Seebeck coefficient in composite ceramics (ZnO)z[(TM)xOy]1 – z (TM = Fe, Co (transition metals); 0 ≤ x ≤ 3, 1 ≤ y ≤ 4, 0.5 ≤ z ≤ 50 wt %), obtained using one- and two-stage technology has been examined. Experimental data on the electrical conductivity, Hall effect, and thermoelectric parameters of doped and undoped ceramics are presented. In the wurtzite phase of the studied ceramics, two levels were found: a shallow level with ionization energy ΔE1 ≈ 0.04–0.05 eV and a deep level with ΔE2 ≈ 0.24–0.37 eV. The relationship between the phase composition, electrical conductivity, and thermoelectric power in the studied ceramics has been established. Doping of zinc oxide with iron is shown to be promising for increasing the Seebeck effect.

Reflection and transmission measurements of thin (40 µm) polyamide films implanted with Co + ions at ion current density of 4µA/cm 2 and fluence range of 2.5 × 10 16 —1.5 × 10 17 cm –2 have been performed in the wave length range of λ = 200—1100 nm. Implantation leads to a significant (up to 80%) decrease in the transmission of the implanted films and an increase in the reflection of both the implanted and nonimplanted sides due to carbonization of the surface layer and the formation of cobalt inclusions in it. Within the framework of two- and three-layer models, which include one or two modified layers and an undamaged part of the film, the transmission of light when incident on the implanted and non-implanted sides was simulated and fluence dependence of the effective refractive index of the modified layer was determined. The effective refractive index was within 1.3—2.1 in the studied fluence range.

Reflection and transmission spectra in the range 200–1100 nm of thin (40 μm) polyamide films implanted with Co+ ions of energy 40 keV at ion-current density 4 μA/cm2 in the dose range 2.5·1016–1.5·1017 cm–2 are measured. The implantation leads to a significant (up to 80%) decrease of transmission through the implanted films and an increase of reflection from both the implanted and nonimplanted sides because of carbonization of the surface layer and formation of cobalt inclusions in it. Transmission of light incident on the implanted and nonimplanted sides was simulated and the dose dependence of the effective refractive index of the modified layer was determined in the framework of two- and three-layer models including one or two modified layers and the undamaged part of the film. The effective refractive index in the studied dose range was within 1.3–2.1.

Electrochemical deposition of cobalt onto the single-layer CVD graphene draw to the formation of Co-CoO/graphene composites with increased electrical resistance and magnetoresistance. It is shown that magnetoresistance is governed with two competing mechanisms – negative (NMR) and positive (PMR). NMR at low magnetic fields could be well described with localized quantum corrections to the Drude conductivity in graphene. The enhancement of PMR at high magnetic fields could be associated with the influence of Lorentz mechanism in Co-CoO particles.

Optical transmission and reflection spectra of monocrystalline zinc oxide (ZnO) plates implanted with 40 keV Co+ ions to high doses of (0.5–1.5)·1017 cm–2 are presented. With increasing dose, the transmission value decreases and the optical transmission edge shifts towards the long-wavelength region in transmission spectra. Also, in the transmission spectra, three absorption bands are observed in the range of 550–680 nm. The bands and their positions are typical of optically active Co2+ ions in the zinc cation substitution positions in the ZnO matrix. The reflection coefficient of the implanted side of the ZnO plate increases monotonically with increasing dose values. In both the initial and implanted ZnO plates, when reflection spectra are recorded from the reverse (nonirradiated) side, a characteristic structure at l = 375 nm is observed due to exciton reflection. Modeling of light transmission and reflection in cobalt-implanted ZnO samples was carried out within the framework of a three-layer model, in which the first surface layer contains cobalt nanoinclusions, the second, deeper layer is a solid solution of cobalt ion substitution in the ZnO matrix, the third layer is the unirradiated part of the ZnO plate. Modeling was used to determine effective refractive indices of two ZnO layers containing implanted cobalt admixture in different phase states.

We measure the reflectance spectra of 1.8 µm-thick FP9120 photoresist films doped with antimony ions and deposited by centrifugation on the surface of p-type silicon wafers (ρ = 10 Ω cm) with a (111) orientation. Implantation leads to a decrease in the refractive index of the photoresist due to the radiation crosslinking of Novolac resin molecules and a decrease in the molecular refraction and density of the photoresist. In the opacity region of the photoresist film, an increase in the reflection coefficient is observed with an increase in the implantation dose.

Optical transmission and reflection spectra of monocrystalline plates of zinc oxide (ZnO) implanted with 40 keV Co + ions to high doses of (0.5-1.5)×10 17 cm - 2 are presented. A decrease in the transmission value and the shift of the optical transmission edge to the long-wavelength region with increasing of the dose are observed in transmission spectra. Three absorption bands in the range of 550-680 nm are also observed in transmission spectra. The bands and their positions are typical for optically active Co 2 + ions in the zinc cation substitution positions in the ZnO matrix. The reflection coefficient of the implanted side of the ZnO plate increases monotonously with the dose values. In both, the initial and implanted ZnO plates, a characteristic structure at λ = 375 nm due to exciton reflection is observed when recording the reflection spectra from the reverse (non-irradiated) side. Modeling of light transmission and reflection in cobalt-implanted ZnO samples was carried out within the framework of a three-layer model, in which the first surface layer contains cobalt nanoclusions, the second, deeper layer is a solid solution of cobalt ion substitution in the ZnO matrix, the third layer is the unradiated part of the ZnO plate. As a result of modeling, effective refractive indexes of two ZnO layers containing implanted cobalt admixture in different phase states were determined.

A method of measuring the reflection spectra was used to study the implantation of photoresist films of the photoluminescence FP9120 with a thickness of 1.8 μm, implanted by antimony ions, deposited by centrifugation on the surface of p-type silicon plates (ρ = 10 Ω cm) with the (111) orientation. It was shown that, implantation leads to the decrease of photoresist refractive index caused by the radiation linkage of novolac resin, as well as the decrease of molecular refraction and photoresist density. In the opacity area of photoresist film reflectance coefficient growth was observed at the increase of implantation dose.

Graphene applications in electronics require experimental study of the formation of high-quality Ohmic contacts and deeper understanding of electron transport mechanisms at metal/grapheme contacts. We have studied carrier transport in twisted CVD graphene decorated with electrodeposited Co particles forming Ohmic contacts with graphene layers. We have compared layer resistivity as a function of temperature and magnetic field R � ( T , B ) for as-synthesized and decorated twisted graphene on silicon oxide substrates. Experiments have proven the existence of negative (induction < 1 Tl) and positive (induction > 1 Tl) contributions to magnetoresistance in both specimen types. The R � ( T , B ) functions have been analyzed based on the theory of 2D quantum interference corrections to Drude conductivity taking into account competition of hopping conductivity mechanism. We show that for the experimental temperature range (2–300 K) and magnetic field range (up to 8 Tl), carrier transport description in test graphene requires taking into account at least three interference contributions to conductivity, i.e., from weak localization, intervalley scattering and pseudospin chirality, as well as graphene buckling induced by thermal fluctuations.

We investigate FP9120 positive photoresist films 1.8 μm thick that are spin-coated on the surface of KDB-10 (111) silicon wafers and implanted with В + and Р + ions by measuring the reflection’s spectra. It is shown that implantation reduces the refractive index of the photoresist. In the opacity region of the photoresist film, the reflection coefficient grows with an increasing implantation dose, especially in the case of P + ion implantation. The spectral dependences of the optical length for the implanted photoresist films have two regions with anomalous dispersion near the wavelengths of 350 and 430 nm, which correspond to the absorption bands of naphthoquinone diazide molecules.