Peter Marjanovych Lytvyn

National Academy of Sciences of Ukraine | ISP · V.E. Lashkarev Institute of Semiconductor Physics

The processes of surface relief formation on GexSe100-x films under their point irradiation by an electron beam have been studied. Electron-induced effects in GexSe100-x films are interpreted in framework of a two-layer charge model. The distribution of the surface potential in the locally irradiated regions of the GexSe100-x film have been establi...

This paper examines the relationship between the groove profile of aluminum gratings and the shape of surface plasmon polariton (SPP) resonances in the angular dependences of specular reflection and −1 diffraction order. Gratings with a period of a = 700 nm were formed on films of As40S30Se30 chalcogenide photoresist by means of interference lithog...

Both first-principles study of the random TiC–NbC solid solutions and experimental investigation of the films in Ti–Nb–C system were carried. The mixing energy, electronic and phonon structures, elastic constants and moduli, hardness, Debye temperature, fracture toughness, dielectric function, electron energy-loss spectra and heat capacity of the r...

The formation of GeSn nanostructures catalyzed by Sn surface droplets during the growth of Ge1-xSnx/Ge/Si(001) heterostructures provide a promising strategy for the growth of high-quality Sn-containing group-IV alloys. The droplet formation is favored by Sn segregation at dislocation cores and diffusion of Sn towards the sample surface. Subsequent...

The influence of microwave radiation (2.45 GHz, 1.5 W/cm ² , up to 80 s) on defects was studied in single crystals of n -6H–SiC, n -GaAs, and epi-GaAs. The capture cross section of the charge carrier was found to change, and defect complexes were reconstructed because of the growing number of interstitial atoms in the near-surface layer. The correl...

We demonstrate the potential of using digital stereo micro-photogrammetry for the analysis and modeling of the habit and sectoral structure of real high-pressure high-temperature single-crystal diamonds. A prototype scanning system with a resolution of 5 μm has been implemented based on a digital single-lens reflex camera, making it possible to cre...

The current transfer through a two-layer structure saturated with absorbed water, each layer of which consists of pressed ZrO2 nanoparticles with two sizes (10 and 20 nm), has been studied. The structure was obtained using the isostatic pressing the ZrO2 + H2O powders. The form of current–voltage characteristics inherent to the studied structure, t...

Boron-doped diamond single crystals of cubo-octahedral habit have been obtained by temperature gradient method at high pressures and high temperatures (HPHT) in Fe-Al-B-C system, and multisectoral plates of different orientations have been produced. Spatial distribution of uncompensated boron impurity and surface potential through the interfaces of...

In this paper we investigate the doping effect of FeO and Fe2 O3 on the structural, optical and magnetic properties of ZnO layers prepared by a new stencil-free technique. Samples were characterized by X-ray diffraction (XRD), atom force and magnetic force microscopy, photoluminescence and Raman spectroscopy. A quite high quality of the printed Fe-...

Polytetrafluoroethylene (PTFE) film was deposited in magnetic field by means of heating of bulk PTFE in vacuum with evaporation of decomposition products. The film thickness and surface relief are dependent on the strength of the magnetic field. We suggest, that a part of gaseous fragments, released from the PTFE during thermal degradation, attach...

Fluoropolymers (FP) are materials with a combination of excellent physical and chemical properties which make them useful in various industries. Thin films of these almost insoluble polymers were deposited with decomposition-evaporation of bulk FP in a vacuum. The pretreatment of the evaporated FP, the pressure of the emitted gas, the activation wi...

VOx films deposited using the multistep method have been investigated. These films were deposited by repeating the two-stage method of low-temperature deposition – low-temperature annealing. The structure and characteristics of VOx thin films have been studied. Taking into account the obtained results, theoretical modeling of the structure was perf...

The effect of surface plasmon-polaritons (SPPs) excited at the interface between the profiled surface of the silver layer (in the form of a diffraction grating) and the As4Ge30S66 layer on the photostimulated diffusion of silver into chalcogenide has been studied. The gratings with the period a = 519 nm and modulation depth h/a ≈ 0.037 (where h is...

In this work morphological, X-ray structural and optical studies of CdZnTe films grown by hot wall epitaxy method at relatively low substrate temperatures were performed. Possible mechanisms and processes of self-organization that occur during the growth of such structures are considered. It is shown that at thickness of film more than 130 nm on th...

The results of studies of printed ZnO:Co polycrystalline layers are first described. The layers with Co concentration of 0.78, 2.09 and 5.42 at.% were printed by a new stencil-free method developed by the authors and then were recrystallized at a temperature 1000–1100 °C. It was shown that the layers were polycrystalline with a typical grain size a...

For the first time, shear-induced metallization on the (001) face of diamond single crystals of types Ib, IIa and IIb during hardness tests is studied. The tests are performed using the Vickers and Berkovich indenters on diamond single crystals grown by the temperature gradient method. In the Raman spectra of imprints obtained on the (001) face of...

Semiconducting boron-doped diamond single crystals of cubo-octahedral habit with prevalent development of octahedron {111} faces and insignificant area of cube {001}, rhombo-dodecahedron {110} and tetragon-trioctahedron {311} faces were obtained using solution-melt crystallization at high pressure 6.5 GPa and temperatures 1380…1420 °C. Using the Fe...

Using laterally ordered arrays of noble metal nanocavities as SERS substrates has been examined theoretically and experimentally. Simulation of the distribution of the electric field at the surface of nanostructures (nanocavities) has been carried out. The simulation results showed that cavities can be formed not only in a metal layer but in semico...

Dichroic organic films have found a broad application in various optoelectronic devices. One efficient method for the production of thin dichroic films is the deposition of the film onto aligning polymer surface. Scientists propose different explanations concerning the mechanisms of the molecules aligning. Here, we report the aligning of squaraine...

Polytetrafluoroethylene (PTFE), polyhexafluoropropylene (PHFP) and polychlorotrifluoroethylene (PCTFE) were heated to their decomposition temperature in a high vacuum. The emitted fragments passed an electron cloud, condensed on a substrate and formed fluoropolymer film. Growth rate of PTFE and PHFP films increased up to a factor five in presence o...

An experimental study of the excitation of surface plasmonpolaritons (SPP) on aluminum diffraction gratings with a fixed period of 519 ± 0,5 nm and a variable modulation depth h/a(where h is the grating depth, and a – its period) was carried out. Gratings with a sine-like profile were formed on vacuum chalcogenide photoresists films by interfere...

Polytetrafluoroethylene (PTFE), polyhexafluoropropylene (PHFP) and polychlorotrifluoroethylene (PCTFE) were heated to their decomposition temperature in a high vacuum. The emitted fragments passed an electron cloud, condensed on a substrate and formed fluoropolymer film. Growth rate of PTFE and PHFP films increased up to a factor five in the presen...

A nondestructive approach is described that is applicable for studying the In-segregation phenomena in ultra-thin In(Ga)As/GaAs nanostructures grown by molecular beam epitaxy. The proposed method utilizes only the experimental photoluminescence (PL) spectroscopy data and the effective bandgap simulation of specially designed ultra-thin In(Ga)As/GaA...

The effect of the surface plasmon polariton excitation at the silver–chalcogenide glass interface on the photostimulated diffusion of silver into chalcogenide was studied. The test sample was a two-layer Ag–As2S3 structure deposited on the diffraction gratings with a 899-nm period made using interference photolithography. Photostimulated changes we...

The effects of growth rate on the structural, morphological, and electrical properties of InN nanostructures grown on [0001]-oriented GaN substrates by plasma-assisted molecular beam epitaxy is reported. Slowing the growth rate of the nanostructures resulted in extended time for reaching thermodynamically favored crystal facet structures, while at...

The monograph highlights the results of the scientific topic "Theoretical and practical aspects of the use of mathematical methods and information technology in education and science" (registration number 0116U004625) by the Department of Computer Science and Mathematics, Faculty of Information Technology and Management, Borys Hrinchenko University...

The chemical and structural modification of thin nanoporous graphitized carbon film was achieved by RF plasma treatment in the atmosphere of Ar, N2 and H2+N2. The effect of carbon surface modification on the resistive sensitivity of gas sensor to water and ammonia vapors is studied. It was shown, that nitrogen and forming gas plasma treatments resu...

We report the results of a study that was conducted to investigate the recombination paths of photoexcited charge carriers in GeSn thin films. The charge carrier lifetime was predicted as a function of temperature from a description of photoconductivity transients, assuming co-influence of Shockley-Read-Hall and radiative carrier recombination path...

The effect of collective trampoline ion-plasma sputtering on the surface properties of metals, insulators, and semiconductors is studied. The structure of the surface, composition and structure of films obtained by trampoline sputtering of various targets (metals, ceramics, silicon and carbon) are studied. The main parameters of the texturing proce...

Two types of ions (fluorine and titanium) are implanted into the film of regio-regular poly(3-hexylthiophene-2,5-diyl) (rr-P3HT) spin-coated on a glass substrate with subsequent annealing in argon atmosphere to modify their electrical properties and structure. The ion energy and fluence were within 0.2–40 keV and 10¹³–10¹⁵ cm⁻² respectively. The dc...

Interaction of AsxSe100-x glass thin films with electron beam was investigated by Atomic force microscopy (AFM), Kelvin force microscopy (KFM), X-ray absorption fine-structure (EXAFS) and X-ray-absorption near-edge (XANES). Electron beam induces different surface reliefs depending on the irradiation dose. At doses equal to 7.4*10² μC/cm² Gausian-li...

The aligning polytetrafluoroethylene (PTFE) layer can be produced by hot friction transfer (FT) of bulk PTFE. The method, which allows to produce aligning PTFE layer at room temperature of substrate, consists of the two stages: 1-heating of the bulk PTFE in vacuum with activation of the emitted gas with cloud of electrons (EVD); 2-consequent unidir...

In spite of the fact that there are different techniques in the creation of the high-quality liquid crystals (LCs) alignment by means of various surfaces, the azimuthal and polar anchoring energies as well as the pre-tilt angle are important parameters to all of them. Here, the modified by a certain manner aligning layers, previously formed by nonl...

New method (magnetron plasma enhanced CVD) is suggested to obtain record values of porosity of thin carbon films. Further high temperature annealing results in graphitization of the carbon film and reduction of their resistivity down to 10 ² Ohm×cm. Plasma treatment in forming gas leads to modification both of a surface and bulk thin nanoporous gra...

Carbon nanoporous thin films are very attractive for application in fields of supercapacitors, fuel cells, gas sensors and others. However due to it very high resistance an employment of this material for resistance gas sensor is problematic. At the same time graphene based materials are very sensitive to different gas ambient and have a resistivit...

In spite of the fact that there are different techniques in the creation of the high-quality liquid crystals (LCs) alignment by means of various surfaces, the azimuthal and polar anchoring energies as well as the pre-tilt angle are important parameters to all of them. Here, the modified by a certain manner aligning layers, previously formed by nonl...

Rare earth metals, when deposited and oxidized on semiconductor surfaces, can be an alternative to unstable compounds of alkali metals while creating stable and effective emitters with a low work function. A procedure giving rise to the adsorption of Gd and O atoms on the Si(100) surface and the formation of a Si–Gd–O film with a work function of a...

The effect of the excitation of surface plasmon polaritons at the silver–chalcogenide glass interface upon the photostimulated diffusion of silver into chalcogenide was studied for the first time. A high-frequency aluminum diffraction grating with a period of 248.5 nm and a deposited two-layer Ag–As2S3 structure was used to excite plasmons. The pro...

Surface-enhanced Raman scattering (SERS) is powerful analytical method for applications in fundamental and applied research. One of the most active field in SERS research relates to the quest for new substrates with improved enhancement efficiency and reproducibility. These efforts include several approaches, such as development of new nanomaterial...

Practical Atomic Force Spectroscopy Assisted by Artificial Neural Networks

Multilayer organic and inorganic systems of thin solid films are widely used in novel optoelectronic devices. The required properties of the system depend on the morphology of the films and transition zone at interfaces. We studied the formation of deposits of fluorinated azo-dyes, polymethine, merocyanine and sulfur-terminated organic compounds (S...

Undoped and Tb-doped ZnO thin polycrystalline films grown on Al2O3 substrate by magnetron sputtering approach were investigated using external infrared reflection in the spectral range from 50 to 5000 cm−1. The modelling of the IR reflection spectra was performed for absorbing film on semi-infinite substrate. For undoped ZnO film, the single oscill...

The effect of substrate material (Si, SiO2,Al2O3) on structural, optical and electrical properties of terbium doped ZnO films (Tb-ZnO) has been investigated by the X-ray diffraction, Raman scattering, atomic force microscopy, photoluminescence and infrared reflection methods. All films consist of micron size clusters of closely packed ZnO grains separat...

Plastic strain relaxation in epitaxial layers is one of the crucial factors that limit the performance of III-nitride-based heterostructures. In this work, we report on strain relaxation and crystalline defects in heterostructures consisting of compositionally graded AlGaN epitaxial layers tensile-strained between a GaN-buffer and a GaN-cap. We dem...

Wepresent a study of the modifications to the optical transmittance of GaN thin film on sapphire due to weak magnetic field (WMF) treatment. Measurements were performed in the 320-1100 nm wavelength range at 300 K, evidencing a change in transmission spectra for wavelengths above 700-800 nmafter theWMFtreatment.Weuse a model with three layers to si...

Graphene oxide (GO) films were formed by drop-casting method and were studied by FTIR spectroscopy, micro-Raman spectroscopy (mRS), X-ray photoelectron spectroscopy (XPS), four-points probe method, atomic force microscopy (AFM), and scanning Kelvin probe force (SKPFM) microscopy after low-temperature annealing at ambient conditions. It was shown th...

Four stainless steel mirror specimens were sputtered to an identical mean thickness of the eroded layer 2 μm with Ar+ ions. Each specimen was exposed to ions with one kinetic energy from the followings: 300, 600, 1000, and 1350 eV. With the methods of microscopy and profilometry of microrelief the positive correlation was shown between the r. m. s....

The dependence of surface potential value on the particle size of micro- and meso-fractions for powdered ZnS:Mn obtained using self-propagating high-temperature synthesis has been investigated. Rather good agreement of model representations for the change in the value of surface potential for the particle with its size changed due to overlapping th...

The effect of electron beam irradiation on the structure and doping of the graphene film located on the silicon dioxide substrate is investigated, and its influence on carrier transport mechanism is discussed. Local potential measurements have shown that the graphene layer synthesized by CVD method on Cu foil has a granular structure with the grain...

The relaxation of built-up strain in the heteroepitaxial GaN/AlN superlattices (SLs) leads to defect-related undesirable changes of the optical and electrical properties of SL-based devices. In the present study, the influence of lattice misfit between the GaN/AlN SL and GaN(0001) substrate on the mechanism of strain relaxation in the SLs is compr...

Photosensitive plasmon-active structures derived from nanostructured gold films and chalcogenide glass As20Se80 have been prepared. Regular sub-wavelength reliefs are formed on the surface of As20Se80 glass due to the interaction of an amorphous chalcogenide glass film located on the metallic film nanostructures of different geometry and a localize...

What would we do without humor?

We experimentally demonstrate that the conductivity of graded AlxGa1-xN increases as a function of the magnitude of the Al concentration gradient (%Al/nm) due to polarization doping effects, without the use of impurity dopants. By using three up/down graded AlxGa1-xN nanolayers with Al gradients ranging from ~ 0.16 to ~ 0.28 %Al/nm combined in one...

The evolution of morphological, structural, and luminescence properties of InN nanostructures grown on [0001]-oriented GaN substrates by plasma-assisted molecular beam epitaxy is reported. By varying the growth temperature, Tgr, by only 100 °C, a dramatic change in the apparent growth mechanism and the resulting surface morphology and nanoscale str...