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Future decades will experience tons of silicon waste from various sources, with no reliable recycling route. The transformation of bulk silicon into SiO2 nanoparticles is environmentally significant because it provides a way to recycle residual silicon waste. To address the needs of silicon recycling, we develop a top-down approach that achieves 100% conversion of bulk silicon to silica nanoparticles with outcome sizes of 8-50 nm. In addition to upcycling the potential of silica, our method also possesses several advantages, such as simplicity, scalability and controllable particle size distribution. Many fields of science and manufacturing, such as optics, photonics, medical, and mechanical applications, require size-controllable fabrication of silica nanoparticles. We demonstrate that control over temperature and hydrolysis time has a significant impact on the average particle size and distribution shape. Additionally, we unravel the process of nanoparticle formation using a theoretical nucleation model and quantum density functional theory calculations. Our results provide a theoretical and experimental basis for silica nanoparticle fabrication and pave the way for further silicon conservation research., 33 pages, 13 figures

Simulation of the irradiation of crystalline silicon with low-energy (50—500 eV) noble-gas ions (He, Ne, Ar, Kr, Xe) is performed using the molecular-dynamics method with damage accumulation. The analysis of structural changes in the near-surface layers of the material demonstrates significant differences between the mechanisms of silicon damage by light and heavy particles. It is shown that, under material irradiation with Xe ions and especially with He ions, the largest clusters are formed by atoms implanted in the material.

Supercapacitors based on carbon nanomaterials are attracting much attention because of their high capacitance enabled by large specific surface area. The introduction of heteroatoms such as N or O enhances the specific capacitance of these materials. However, the mechanisms that lead to the increase in the specific capacitance are not yet well-studied. In this Letter, we demonstrate an effective method for modification of the surface of carbon nanowalls (CNWs) using DC plasma in atmospheres of O

The properties of nanocomposites based on heat-resistant organosoluble copolyimide are studied. The nanocomposites are obtained by the sol−gel technique; nanoparticle formation occurs in situ in the polymer-matrix bulk. Metalloalkoxysiloxanes, namely tetrakis-(methyldiethoxysiloxy)hafnium and pentakis-(methyldiethoxysiloxy)niobium, are used as precursors of the filler phase. It is shown that the in-situ filling of copolyimide contributes to an increase in the order of material resistance to the effects of an atomic oxygen flow, reducing surface degradation during irradiation in comparison with an unfilled matrix.

A complex simulation approach is applied to determine optimal conditions for the functionalization of low- k materials in e-beam rf discharge generated by 1 keV electron beam in He. The possibility and mechanisms of methyl group elimination from low- k surfaces with low-energy He ions and fast He atoms are studied with ab initio dynamic density functional theory-based simulations. The effect of gas pressure, rf voltage, and rf frequencies on the ion energy and angle distribution functions is analyzed using a 1D Particle-in-Cell Monte Carlo model. The relative contribution of fast atoms in the surface functionalization is estimated. Ion fluxes on the 2D trench walls and bottom are calculated with the developed analytical approach.

Implantation and subsequent behaviour of heavy noble gases (Ar, Kr, Xe) in few-layer graphene sheets and in nanodiamonds is studied both using computational methods and experimentally using X-ray absorption spectroscopy. X-ray absorption spectroscopy provides substantial support for the Xe-vacancy (Xe-V) defect as a main site for Xe in nanodiamond. It is shown that noble gases in thin graphene stacks distort the layers, forming bulges. The energy of an ion placed in between flat graphene sheets is notably lower than in domains with high curvature. However, if the ion is trapped in the curved domain, considerable additional energy is required to displace it., Accepted to Physical Chemistry Chemical Physics

In this paper the excitations of collective electronic modes and currents induced in nanostructured semiconductor systems by two-mode quantum light with non-zero orbital angular momenta are investigated. Transfer of photon correlations to the excitations and currents induced in the semiconductor system is demonstrated. Birth of correlated electrons arising in the conduction band of the nanostructure due to the interaction with correlated photons of quantum light is found. Azimuthal and radial spatial distributions of the entangled electrons are established. The obtained results make possible to register the correlated electrons experimentally and to implement quantum information and nanoelectronics circuits in nanosystems using the found azimuthal and radial electron entanglement.

The influence of the form of the Ar–Si interatomic potential on the results of simulating the physical sputtering of amorphous Si by low-energy Ar ions is analyzed. The yields of Si sputtering by Ar ions with an energy of 50–300 eV at normal incidence are calculated using the molecular dynamics (LAMMPS software) and the Monte Carlo methods by means of the MOTREV program developed at the Skobeltsyn Institute of Nuclear Physics, the Moscow State University, and used quantum-mechanical elastic-scattering cross sections. The semiempirical Moliere and ZBL pair potentials and a potential developed on the basis of density functional theory calculations are applied to describe Ar–Si interaction. The energy dependences of the sputtering yields obtained using different potentials are analyzed in this paper. Conclusions concerning the applicability of the considered Ar—Si interaction potentials to simulation of the physical sputtering of amorphous Si in the indicated range of projectile energies are drawn.

The role of porosity and pore size in the morphological changes of nanoporous materials during low-energy ion irradiation is studied in terms of crystalline-silicon models. Molecular dynamics simulations are implemented to study the destruction of porous structures with different values of the porosity and pore size. The obtained dependences of the potential energy and specific surface area on the system temperature are used to determine the material parameters, at which the process of pore compression occurs.

In this paper we have carried out molecular dynamics simulation of the low-energy Ar ion irradiation of nanoporous homogeneous material with different porosity and pore sizes. Our results demonstrate that in a model with small pores (Rpore = 0.8 nm) and relatively low (22%) porosity, the pores at near-surface layers collapsed due to the ion bombardment, whereas in a model with larger pores (Rpore = 2.8 nm) and higher (44%) porosity no significant structural changes occurred under the same irradiation conditions. To study thermal stability of porous structures and to reveal the effects of both the pore radius and the porosity on pore collapsing, our nanoporous structures were subjected to gradual heating. The simulation results demonstrate distinct mechanisms of structural changes in the nanoporous materials depending on the value of the excess surface energy per unit volume.

The cleaning of two-dimensional (2D) materials is an essential step in the fabrication of future devices, leveraging their unique physical, optical, and chemical properties. Part of these emerging 2D materials are transition metal dichalcogenides (TMDs). So far there is limited understanding of the cleaning of “monolayer” TMD materials. In this study, we report on the use of downstream H2 plasma to clean the surface of monolayer WS2 grown by MOCVD. We demonstrate that high-temperature processing is essential, allowing to maximize the removal rate of polymers and to mitigate damage caused to the WS2 in the form of sulfur vacancies. We show that low temperature in situ carbonyl sulfide (OCS) soak is an efficient way to resulfurize the material, besides high-temperature H2S annealing. The cleaning processes and mechanisms elucidated in this work are tested on back-gated field-effect transistors, confirming that transport properties of WS2 devices can be maintained by the combination of H2 plasma cleaning and OCS restoration. The low-damage plasma cleaning based on H2 and OCS is very reproducible, fast (completed in a few minutes) and uses a 300 mm industrial plasma etch system qualified for standard semiconductor pilot production. This process is, therefore, expected to enable the industrial scale-up of 2D-based devices, co-integrated with silicon technology.

Selective deposition of various materials on pre-defined areas on the substrate is of crucial importance nowadays for microelectronic technology. Carbon-based layers, such as self-assembled monolayers and polymerized fluorocarbon etch residues are often used as passivation layers in order to inhibit the deposition of the required material. In our previous paper, we reported on selective ALD of Ru enabled by H2 plasma passivation of amorphous carbon (a-C) as the non-growth surface and simultaneous activation of a SiCN growth surface. In the present work, we demonstrate a-C modification by H radicals in the absence of H ions in a downstream plasma chamber. The H radical treatment significantly improves the ALD selectivity with respect to the standard H2 plasma treatment by reducing the number of unwanted hydroxyl groups on the a-C surface and providing strong chemical modification of the a-C via surface hydrogenation. In addition, the H radical treatment results in the zero-damage of the a-C film and, therefore, it does not change the pattern profile or the aspect ratio. The experimental data and the investigation of the interaction mechanism between H2 plasma and the a-C surface were supported by molecular dynamic modeling, where effects of the a-C modification by H ions and H radicals were decoupled. The chemical modification of the a-C surface by H radicals results in 10 nm Ru being deposited on Si-based dielectric substrates, while no Ru can be detected by high-resolution RBS on a-C. The H radical surface treatment was also tested on patterned structures with 45 nm half-pitch a-C lines on the SiCN surface.

The structure and properties of nanocomposites based on organosoluble polyimide (PI) and branched functional metallosiloxane oligomers with different types of central metal atoms (Al, Cr, Fe, Zr, Hf and Nb) were investigated. Under the same weight content of the filler, the geometric parameters of the nanoparticles and thermal properties of the nanocomposites did not exhibit a direct relationship with the ability of the materials to withstand the incident flow of oxygen plasma. The atomic oxygenerosion resistance of the filled PI films was influenced by the composition of the hybrid fillerand the type of metal atom in the hybrid filler in the base metallosiloxane oligomer. To determine the effectiveness of the nanoparticles as protective elements of the polymer surface, the nanocomposite erosion yields pertaining to the concentration of the crosslinked organo&ndash, inorganic polymer forming the dispersed phase were determined and expressed in mmol per gram PI. The filler concentration in the polymer, expressed in these units, allows for comparison of the efficiency of different nanosize fillers for use in fabricating space survivable coatings. This can be important in the pursuit of new precursors, fillers for fabricating space survivable polymer composites.

The mechanisms of H atoms interactions with single-layer MoS

The selective deposition of materials on predefined areas on a substrate is of crucial importance for various applications, such as energy harvesting, microelectronic device fabrication, and catalysis. A representative example of area-confined deposition is the selective deposition of a metal film as the interconnect material in multilevel metallization schemes for CMOS technology. This allows the formation of multilevel structures with standard lithographical techniques while minimizing pattern misalignment and overlay and improving the uniformity of the structures across the wafer. In this work, area-selective deposition of Ru by atomic layer deposition (ALD) is investigated using alkoxy siloxane dielectric passivation layers. In this work, a comparison of several silane organic SAM precursors in terms of Ru ALD ASD performance is reported. The importance of the surface areal concentration of the passivation molecules is demonstrated. According to the in situ X-ray photoelectron spectroscopy film characterization, the ALD blocking layers derived from a (3-trimethoxysilylpropyl) diethylenetriamine (DETA) precursor have the ability to polymerize under ALD-compatible temperatures, such as 250 °C, which leads to a significant inhibition of Ru growth up to 400 ALD cycles. At the same time, the DETA layer can be selectively removed from the oxidized Cu surface by rinsing in acetic acid, which allows selective deposition of ca. 14 nm of Ru on Cu with no Ru detected on the DETA-coated surface by RBS. The approach is successfully tested on 50 nm half-pitch patterned SiO2/Cu lines.

The process of the physical sputtering of the (001) surface of continuous and nanoporous crystalline silicon by 100- and 200-eV Ar ions is simulated using the molecular dynamics method. The features of the process in porous materials are revealed. The dependences of the sputtering yield on the fluence and energies of incident ions are obtained. The structural changes under ion bombardment are described. The dissimilarity between the sputtering mechanisms for materials differing in pore radii and the degree of porosity is demonstrated.

The possible reactions between thermal F atoms and SiCF3 surface groups are simulated using density functional theory. These reactions constitute a part of the multistage mechanism by which SiOCH films are damaged and etched by fluorine radicals. The results of simulation demonstrate that a probable channel for removing carbon-containing compounds from the surface is the generation of volatile CF3 radicals with the simultaneous formation of SiF surface groups. The probability of the separation of a CF4 molecule is low due to a forbidding activation barrier of ~1.4 eV.

Currently, the prospects for replacing traditional materials with quasi-two-dimensional compounds based on transition metal dichalcogenides are actively being studied. The quasi-two-dimensional molybdenum disulfide MoS2, a semiconductor with a finite band gap, can be used either as a standalone material or as a part of layered heterostructures. When creating nanosized electronics elements based on such ultrathin materials, the application of an atomic layer etching technology is of key importance. In this paper, a brief description of the properties of MoS2 monolayers in comparison with graphene and the monolayers of hexagonal boron nitride is considered. On the basis of the results of computer simulation by means of a DFT (density functional theory) method, effects caused in the MoS2 monolayer by chlorine atoms and molecules widely used in the state-of-the-art of atomic layer etching applied to silicon materials are demonstrated.

This paper presents results of experimental investigation of combined impact of 500 keV protons with fluences of 10 15 –10 16 cm −2 and oxygen plasma with fluences of (0.8–3.5) 10 20 cm −2 on polyimide films. Measured UV–vis transmission, Raman and XPS spectra of polyimide specimens before and after combined impact and data on the sample mass losses as a result of erosion due to oxygen plasma exposure are given. On the base of the obtained spectroscopic results, the changes in the polyimide structure caused by the proton and oxygen irradiation are analyzed and discussed.

Poly-pyromellitimide and polyamideimide film samples and their modifications obtained with a carbon filler (diamond blend) were irradiated with atomic oxygen flow at an average particle energy of 20 eV. Weight erosion coefficients were calculated for the initial and modified polyimides and a comparative analysis of the resistance of the film samples was carried out. The morphology of the film surface was studied after irradiation with atomic oxygen via scanning electron microscopy. An increase in the percentage of filler in the polymer matrix caused a slight increase in the resistance of the film samples to the effect of atomic oxygen.

This paper presents the results of solid microparticle fluxes in-flight measurements on the Salyut-6, Salyut-7, Mir space stations and the International Space Station over a 33-year period (1978–2011). Fluxes of microparticles within size range of 10–500 μm were evaluated by analyzing the number and sizes of holes in thermal control coatings of plastic track detector for heavy nuclei of cosmic rays (the PLATAN experiment) and by studying craters in polished samples of some ductile and brittle materials and on the surface of a specimen cartridge (the KOMPLAST experiment). Some measurements of PLATAN (2002–2004) and KOMPLAST (1998–2011) experiments on International Space Station were carried out simultaneously. In this paper the experimental data obtained in both experiments are compared with each other as well as with results of other experiments and with ORDEM model predictions.

The brief history of the development of investigations at the Skobeltsyn Institute of Nuclear Physics, Moscow State University (SINP MSU) in the field of space materials science is outlined. A generalized scheme of a numerical simulation of the radiation impact on spacecraft materials and elements of spacecraft equipment is examined. The results obtained by solving some of the most important problems that modern space materials science should address in studying nuclear processes, the interaction of charged particles with matter, particle detection, the protection from ionizing radiation, and the impact of particles on nanostructures and nanomaterials are presented.

Cycling stability and specific capacitance are the most critical features of energy sources. Nitrogen incorporation in crystalline carbon lattice allows to increase the capacitance without increasing the mass of electrodes. Despite the fact that many studies demonstrate the increase in the capacitance of energy sources after nitrogen incorporation, the mechanism capacitance increase is still unclear. Herein, we demonstrate the simple approach of plasma treatment of carbon structures, which leads to incorporation of 3 at.% nitrogen into Carbon NanoWalls. These structures have huge specific surface area and can be used for supercapacitor fabrication. After plasma treatment, the specific capacitance of Carbon NanoWalls increased and reached 600 F g−1. Moreover, we made a novel DFT simulation which explains the mechanism of nitrogen incorporation into the carbon lattice. This work paves the way to develop flexible thin film supercapacitors based on carbon nanowalls.

The effect of branched functional metallosiloxane oligomers (BFMSO) used as precursors on the morphology and atomic oxygen resistance of filled polyimide films was studied. Nanocomposites are characterized by elevated glass transition temperatures and greater erosion resistance to atomic oxygen than the original polymer. In situ filling of polyimide with BFMSO-based nanoparticles allows one to reduce the rate of film mass loss under the influence of atomic oxygen by an order of magnitude and reduce the erosion yield by more than 70%. To correctly compare the effectiveness of fillers based on precursors of different chemical structures as protective elements of the polymer surface from the effects of atomic oxygen, the specific erosion yields calculated as the ratio of the erosion yield to the filler concentration expressed in moles of filler per unit mass of polymer were used. This approach made it possible to identify the main factors of the directional regulation of erosion resistance of in situ filled PI to the effects of atomic oxygen. Primarily they include the chemical structure of the organic frame of the central metal atom of the precursor, which determines the effectiveness of the filler in increasing the erosion resistance of nanocomposites. The “replacement” of a phenyl substituent with a methyl substituent at a silicon atom in the composition of BFMSO and, accordingly, particles based on it, reduces the specific erosion yields of nanocomposites by 2.2-2.6 times. The nature of the central metal atom of the precursor is a minor factor. Its change allows reducing the specific erosion yields of coatings based on polyimide and branched functional metallosiloxane oligomers by no more than 1.5 times.

This paper describes results of ground-based simulation of atomic oxygen influence on samples of polymer composites with different fillers. Polyimide and polyamide-imide were used as matrices, and polyorganosiloxanes, inorganic nanoparticles of Al2O3, TiO2, WC, multiwalled carbon nanotubes, and detonation nanodiamonds were used as fillers. Data on mass loss of composite samples due to atomic oxygen exposure and results of surface morphology analysis are given.

Plasmachemical and heterogeneous processes of generation and loss of ozone in the atmosphericpressure dielectric barrier discharge in oxygen are studied theoretically. Plasmachemical and electronic kinetics in the stage of development and decay of a single plasma filament (microdischarge) are calculated numerically with and without allowance for the effects of ozone vibrational excitation and high initial ozone concentration. The developed analytical approach is applied to determine the output ozone concentration taking into account ozone heterogeneous losses on the Al2O3 dielectric surface. Using the results of quantummechanical calculations by the method of density functional theory, a multistage catalytic mechanism of heterogeneous ozone loss based on the initial passivation of a pure Al2O3 surface by ozone and the subsequent interaction of O3 molecules with the passivated surface is proposed. It is shown that the conversion reaction 2O3 → 3O2 of a gas-phase ozone molecule with a physically adsorbed ozone molecule can result in the saturation of the maximum achievable ozone concentration at high specific energy depositions, the nonstationarity of the output ozone concentration, and its dependence on the prehistory of ozonizer operation.

The results of experimental investigation of the combined action of 500-keV protons and ~20-eV oxygen plasma on thin polyimide films are presented. The samples are irradiated with a proton fluence of 1014–1016 cm–2 and an oxygen plasma fluence of ~1020 cm–2. The transmission and Raman spectra of the films, which are measured at different stages of sample irradiation, are compared. Data on the mass loss of the samples as a result of surface erosion are presented.

We present the results of the simulation tests of samples of polymer nanocomposites based on carbon nanotubes for resistance to oxygen plasma in the Earth’s upper atmosphere. Data on the weight loss of the samples, the results of analysis of their surface structure after irradiation, and data on arrays of carbon nanotubes damaged under the effect of oxygen plasma are given. Possible mechanisms of destruction of the nanotubes are discussed.

This paper deals with different mechanisms of the interaction of light and heavy low-energy ions with nanoporous structures and main structural changes that occur in these structures under irradiation. The study was carried out using the molecular dynamics method for silicon models with pores of radius of 8 and 28 A, which are structural analogs of porous films with low dielectric constant (low-k materials). Based on the results obtained, the mechanisms of interaction of light and heavy noble gas ions (He, Ne, Ar, and Xe) with these structures were compared, and the effects of ion mass and energy on processes of pore sealing were studied.

The mechanisms of H atoms interactions with single-layer MoS2, a two-dimensional transition metal dichalcogenide, are studied by static and dynamic DFT (density functional theory) modeling. Adsorption energies for H atoms on MoS2, barriers for H atoms migration and recombination on hydrogenated MoS2 surface and effects of H atoms adsorptions on MoS2 electronic properties and sulfur vacancy production were obtained by the static DFT calculations. The dynamic DFT calculations give insight into the dynamics of reactive interactions of incident H atoms with hydrogenated MoS2 at H atoms energies in the range of 0.05-1 eV and elucidate the competitive mechanism of hydrogen adsorption and recombination that limits hydrogen surface coverage at the level of 30%. Various pathways of S-vacancies production and H atoms losses on MoS2 are calculated and the effects of MoS2 temperature on these processes are estimated and discussed.

In this paper, a new kind of space-durable nanocomposites has been prepared using one-step in situ method of filling organosoluble polyimides (PI). Three types of metalloalkoxysiloxanes (tris-(diethoxymethylsiloxy) aluminum, tetrakis-(diethoxymethylsiloxy) zirconium, pentakis-(diethoxymethylsiloxy) niobium) were used as filler precursors. It is demonstrated that the nanosized filler particles formed in the polymer volume have a hybrid chemical structure and contain М-О-Si and Si–O–Si bonds. The in situ filling of PI preserves its unique thermal properties, increases the glass transition temperature, and maintains high stability to the thermal oxidation of the matrix PI. The atomic oxygen (AO) erosion resistance of the filled PI has been investigated by exposing its surface to a variety of AO fluences. The introduction of nanosized filler in PI contributes to a sharp, order-of-magnitude decrease in the AO erosion coefficient of the nanocomposite. The valence of the central metal atom of the precursor predetermines the silica-block content in the forming filler and its atomic oxygen AO-protective function. During the transition from a precursor with a trivalent metal atom to a precursor with a tetra- or pentavalent metal atom, the erosion coefficient of filled PI decreases at a constant fluence of AO. Taking into account that the M-O bond energy in a M-O-Si group is higher than the Si–O bond energy, the presence of such atoms as Zr or Nb in the chemical structure of the filler can act as a “reinforcing” element that increases the resistance of the protective layer against AO action.

A new binary collision approach for the calculation of the sputtering yield of Si under nonreactive ionic bombardment by Ar+ is presented for the energy range from threshold to 200 eV. Unlike conventional Monte Carlo approaches that use a classical calculation of the scattering angle from a known potential, their approach employs quantum-mechanical methods to compute the scattering angle. Comparison of the energy and angular dependence of sputtering yields computed using their new quantum-based method with experimental data and with transport of ions in matter (TRIM) and molecular dynamics (MD) calculations supports the accuracy and usefulness of their approach. It is shown that their new approach leads to results of an accuracy intermediate between that of the TRIM and MD methods. The authors expect the new approach to be useful in plasma processing applications.A new binary collision approach for the calculation of the sputtering yield of Si under nonreactive ionic bombardment by Ar+ is presented for the energy range from threshold to 200 eV. Unlike conventional Monte Carlo approaches that use a classical calculation of the scattering angle from a known potential, their approach employs quantum-mechanical methods to compute the scattering angle. Comparison of the energy and angular dependence of sputtering yields computed using their new quantum-based method with experimental data and with transport of ions in matter (TRIM) and molecular dynamics (MD) calculations supports the accuracy and usefulness of their approach. It is shown that their new approach leads to results of an accuracy intermediate between that of the TRIM and MD methods. The authors expect the new approach to be useful in plasma processing applications.

The Komplast materials experiment was designed by Khrunichev State Research and Production Space Center together with Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University and other Russian scientific institutes, and has been carried out by Mission Control Moscow since 1998. The purpose of this experiment is to study the complex effect of the low Earth orbit environment on samples of various spacecraft materials. On November 20, 1998 the Komplast experiment began with the launch of the first International Space Station module Zarya , or Functional Cargo Block (FGB). Eight Komplast panels with samples of materials and sensors were installed on the outer surface of FGB module. Two of eight experiment panels were retrieved during Russian extravehicular activity in February 2011 after 12 years of space exposure and were subsequently returned to Earth by Space Shuttle “Discovery” on the STS-133/ULF-5 mission in March 2011. The article presents the results obtained from this unique long-duration experiment on board of the International Space Station.

Direct molecular dynamic simulation on the base of the density functional theory (DFT) method is used to study some critical reactions of F atoms with organosilicate glass (OSG) low-κ films. Here static and dynamic DFT-based approaches are applied for a variety of reactive pathways of hydrogen and carbon removal in the form of volatile products (HF, CF2 and CF3 molecules) from initial SiCH3 surface groups. These reactions constitute an important part of the proposed multi-step mechanism of OSG films damage and etching by thermal F atoms. Two models (POSS and TMCTS macromolecules and their modifications) are used to illustrate the peculiarities and dynamics of the successive reactions of F atoms with the initial SiCH3 and appeared SiCH x F y (x + y ≤ 3) surface groups.

Fluorine atoms interactions with organosilicate glass (OSG)-based low-κ dielectric films are experimentally and theoretically studied. One-dimensional 1-D Monte Carlo & gas-surface kinetics (MC&GSK) model and density functional theory (DFT) simulations used for the development of the multi-step mechanism of OSG films damage and etching are further verified on FTIR spectroscopy data. DFT method is applied to calculate vibrational mode frequencies and their shifts under F atoms flux. In the frame of 1-D model, evolutions of the SiCH3 and appeared SiCH x F y surface groups distributions inside the porous films are calculated as a function of F atoms dose. F atoms quasi-chemisorption on surface SiO x groups accompanied by fourth-coordinated Si atoms transition to pentavalent Si states is related with the experimentally observed fast fluorination stage and vibrational frequency shifts. In addition, quasi-chemisorbed F atoms induce the weakening of the adjacent Si–O bonds in O x SiF y surface complexes promoting breaks of these Si–O bonds under further F atoms attacks. Quasi-chemisorbed F atoms could be also responsible for F atoms recombination on SiO x surfaces.

Damage of porous organosilicate glass (OSG) films with low dielectric constants (low-κ films) in plasma processing is a critical problem for modern microelectronics. For this problem, understanding and revealing of basic reaction steps for radicals etching and damage are of importance. Previously we have studied experimentally and theoretically the etching and damage of low-κ dielectric films under oxygen and fluorine atoms. Here the effects of N atoms on OSG films are studied experimentally by Fourier Transform InfraRed (FTIR) spectroscopy method and theoretically by density functional theory (DFT) method. Experimental FTIR spectra are compared with calculated vibrational spectra to reveal the relevant surface SiCH x N y groups which could be produced in multi-step reactive collisions of N atoms in ground and lower metastable states with OSG low-κ dielectric films.

This paper deals with physical fundamentals of nanomaterial structure and properties, their classification and the peculiarities of different classes, and the main potential applications of these materials in the next generation spacecraft. Some results of the experimental and mathematical simulation of the space environment influence on nanostructures are given.

This paper presents results of simulation of processes of the oxygen atom impact on carbon and boron nanotubes with ab initio (DFT) and semi-empirical (SCC DFTB) methods. Our calculations demonstrated that the impact of oxygen atoms may cause the nanotube elongation and unzipping. We performed DFTB simulations of the impact of hyperthermal oxygen atoms on graphene and carbon nanotubes of small diameter in the case of a low-coverage regime to obtain a detailed picture of the formation of different oxygen-containing groups on their surfaces.

Features of formation and migration of radiation-induced defects in carbon nanotubes (CNT) and nanostructured materials are examined. The main methods and software tools used for the simulating nanomaterial structure and space factors are described. The results of mathematical simulation are presented.

Damage of porous organosilicate glass films with low dielectric constants (low-k films) in plasma processing is a critical problem for modern microelectronics. For this problem, understanding and revealing of basic reactions for radical (e.g., O, F, and N atoms) interactions with low-k films are of importance. In this study, reactions of initial (Si‒CH3) and appeared (Si‒CHxNy) surface groups with incident N atoms in the ground and excited metastable states were simulated systematically by the dynamic density functional theory (DFT) method. On the basis of a large amount of calculated vibrational modes of various N-containing groups and reaction trajectories, the most important Si‒CHxNy groups for the explanation of obtained experimental data were selected and the most probable reaction pathways were found and described in detail. The proposed reaction mechanism revealed by DFT modeling is used to analyze and to explain the measured FTIR spectra changes with N atom doses and temperatures of porous low-k films.Damage of porous organosilicate glass films with low dielectric constants (low-k films) in plasma processing is a critical problem for modern microelectronics. For this problem, understanding and revealing of basic reactions for radical (e.g., O, F, and N atoms) interactions with low-k films are of importance. In this study, reactions of initial (Si‒CH3) and appeared (Si‒CHxNy) surface groups with incident N atoms in the ground and excited metastable states were simulated systematically by the dynamic density functional theory (DFT) method. On the basis of a large amount of calculated vibrational modes of various N-containing groups and reaction trajectories, the most important Si‒CHxNy groups for the explanation of obtained experimental data were selected and the most probable reaction pathways were found and described in detail. The proposed reaction mechanism revealed by DFT modeling is used to analyze and to explain the measured FTIR spectra changes with N atom doses and temperatures of porous low-k f...

Atomic oxygen (AO) exposure and hard microparticle impact on polyimide nanocomposites were performed by a ground-based magnetoplasmodynamic accelerator and electrostatic accelerator, respectively. The computer simulation of the AO erosion of polyimide nanocomposites was carried out with Monte Carlo method. It is found that the polyimide nanocomposites are significantly more durable to AO exposure than the pure polyimide material. Besides, in the case of combined hard microparticle impact and AO exposure, the regions around craters created by hard microparticle impact are etched more intensively than the undamaged areas of the polyimide nanocomposite sample surface.

The main methods for simulating the impact of radiation on nanostructures are considered. The quantum mechanical density functional method and the semi-empirical density functional tight-binding method are chosen on the basis of an analysis of their applicability to studying the formation of radiation defects in nanostructures in different ranges of space-time. The results from simulating vacancy formation in carbon and boron nitride nanostructures under the impact of H and O atoms with energies of 1–200 eV are presented.

The article discusses the results of mathematical and experimental simulation of the impact of atomic oxygen of the Earth’s upper atmosphere on carbon and boron nitride nanotubes, graphene, hexagonal boron nitride sheets, and graphene nanoribbons, as well as composites based on polymer matrices with fillers in the form of nanosized particles of various types.

Polyimide thin films both unmodified and modified with hyperbranched polyethoxysiloxane were treated with accelerated oxygen plasma flow to imitate a low Earth orbit environment. The resulting changes in the surface morphology were studied using scanning electron microscopy. The erosion yield values were calculated and the relative stability of the tested samples was established. It was shown that the polyimide-polyethoxysiloxane composites have higher atomic oxygen resistance owing to, presumably, the siloxane particles dispersed uniformly in the polyimide matrix. The study found that all plasma-treated samples exhibit the same fibrous, carpet-like surface morphology with some minor variations caused by differences in the chemical composition of polymers.

In this paper, the authors carried out a molecular dynamics simulation of crystal and amorphous silicon sputtering by low-energy (200 eV) Ar ions at normal incidence. The gradual damage of silicon caused by the ion bombardment was taken into account in order to study the dynamics of argon accumulation and clustering. For describing interatomic Ar–Si interaction, they used three different potentials: two binary screened Coulomb potentials (Moliere and Ziegler–Biersack–Littmark) and the potential developed on the basis of density functional theory. The obtained results demonstrated the substantial influence of the chosen Ar–Si potential on calculated sputtering yields and on the processes of argon accumulation and clustering.

The multistep reactions mechanism of F atoms interaction with SiOCH low-κ dielectric films, developed on the base of the measured evolution of various surface groups (e.g., Si-CH3) and systematic density functional theory quantum mechanical calculations, was incorporated into the three-dimensional Monte Carlo model of the damage and etching processes. The model is realized on model maps of porous films and allows us to obtain dynamic 3D images of etching porous films and a layer by layer distribution of components that are formed during the etching. Comparison of calculated etching rates of SiOx matrix by fluorine atoms with the experimental data is used to determine the effective etching probabilities (reciprocal values of F atoms collisions with SiOx matrix groups that are required to remove one of them). The detailed space-resolved dynamics of damage and etching processes of low-κ films with different parameters (porosity, pore, and interpore channels sizes, dielectric permittivity) was obtained and di...