Oxygen Implantation Research Articles

Ion irradiation and implantation modifications of magneto-ionically induced exchange bias in Gd/NiCoO

Magneto-ionic control of magnetic properties through ionic migration has shown promise in enabling new functionalities in energy-efficient spintronic devices. In this work, we demonstrate the effect of helium ion irradiation and oxygen implantation on magneto-ionically induced exchange bias effect in Gd/Ni0.33Co0.67O heterostructures. Irradiation using He+ leads to an expansion of the Ni0.33Co0.67O lattice due to strain relaxation. At low He+ fluence (≤2 × 1014 ions cm−2), the redox-induced interfacial magnetic moment initially increases, owing to enhanced oxygen migration. At higher fluence, the exchange bias is suppressed due to reduction of pinned uncompensated interfacial Ni0.33Co0.67O spins. For oxygen implanted samples, an initial lattice expansion below a dose of 5 × 1015 cm−2 is subsequently dominated at higher dose by a lattice contraction and phase segregation into NiO and CoO-rich phases, which in turn alters the exchange bias. These results highlight the possibility of ion irradiation and implantation as an effective means to tailor magneto-ionic effects.

Effect of Oxygen Ion Implantation on Physicochemical Structure and Corrosion-Electrochemical Behavior of High-Chromium Steel

Effect of Oxygen Ion Implantation on Physicochemical Structure and Corrosion-Electrochemical Behavior of High-Chromium Steel

Effect of Oxygen Ion Implantation on Physicochemical Structure and Corrosion-Electrochemical Behavior of Copper–Manganese Alloy

Effect of Oxygen Ion Implantation on Physicochemical Structure and Corrosion-Electrochemical Behavior of Copper–Manganese Alloy

Влияние имплантации ионов аргона и кислорода на физико-химические и коррозионно-электрохимические свойства хромоникелевой стали 14Х17Н2

The effect of argon and oxygen ion implantation both in separate and joint was carried out. Physical and chemical structure of the surface and corrosion-electrochemical behavior of 14Cr17Ni2 chromium-nickel steel was studied. Methods of potentiometry, atomic force microscopy, X-ray photoelectron spectroscopy, and microhardness measurement were used. It was found that the initial chromium-nickel steel exhibits high corrosion resistance in the medium of a borate buffer solution with the addition of a local corrosion initiator — potassium sulfate. However, steel was found to be susceptible to local (pitting) corrosion in this environment. It is shown that the implantation of argon and oxygen ions changes the nature of the corrosion-electrochemical behavior of chromium-nickel steel. Treatment with Ar+ ions enriched the sample surface with Cr atoms and reduces the overall corrosion losses of steel, but is characterized by the maximum value of local corrosion. Treatment with O+ ions provide optimal results in terms of reducing local and general corrosion. It was found that in this case, the sample surface is intensively oxidized to a depth of more than 20 nm, resulting in the formation of mixed oxides that are resistant to corrosion. There is a process similar to electropolishing of the sample surface due to partial dissolution of steel. Defects in the structure of the sample surface, on which pitting corrosion began, are “healed”. Joint treatment with Ar+ ions and O+ ions does not give noticeable advantages compared to separate implantation with these ions. Corrosion losses for samples treated only with O+ ions and Ar+ ions together with O+ ions did not exceed those for the original sample, although there are practically no passivation regions on the potentiodynamic curves. Microhardness of the samples after ion implantation coincides with the microhardness of the original sample. Result of ion implantation is no significant for change in the structural and phase structure of the surface layers of chromium-nickel steel. Ion implantation will not negatively affect the physical and mechanical properties of studied steel. The research shows that it is advisable to choose the type of implantable ions and the optimal process parameters depending on the steel grade and its application. For these purposes, the research methodology proposed in this article will be useful.

Ионный синтез структур кремний на изоляторе" со свинцово-силикатным изолирующим слоем

The process of ionic synthesis of “silicon-on-insulator” structures based on the sequential implantation of oxygen ions and a glass former into silicon substrates has been investigated. Lead ions were used as a glass former. The features of the formation of a buried silicate layer during post-implantation annealing are considered. The current-voltage characteristics of the synthesized structures, as well as the specific electrical resistances of the insulator and the device silicon layer, have been measured.

Lithium niobate planar and ridge waveguides fabricated by 3 MeV oxygen ion implantation and precise diamond dicing

We report on the fabrication and optimization of lithium niobate planar and ridge waveguides at the wavelength of 633 nm. To obtain a planar waveguide, oxygen ions with an energy of 3.0 MeV and a fluence of 1.5×1015 ions/cm2 are implanted in the polished face of LiNbO3 crystals. For planar waveguides, a loss of 0.5 dB/cm is obtained after annealing at 300°C for 30 min. The ridge waveguide is fabricated by the diamond blade dicing method on optimized planar waveguides. The guiding properties are investigated by prism coupling and end-face coupling methods.

A review on surface treatment of titanium implant

Dental implants are fixtures that serve as replacements for the root of the missing natural tooth and in the current day dental practice. Success or failure of the dental implant treatment is mainly based on the principles of osseointegration, which is the direct and stable anchorage of an implant due to the formation of bony tissue around the implant. A number of systemic and local factors influence the production of an osseointegrated interface and therefore the stability of the implant. Present article covers various methods used for surface treatment of titanium and titanium alloy implants. They are mechanical method such asMachining,Grinding,Polishing and Grit blasting. Chemical treatment include Acid treatment,Hydrogen peroxide treatment,Alkali treatment.Sol–gel coatings include TiO2 coating,Calcium phosphate coatings, Titania/hydroxyapatite composite coatings and Silica coating.Electrochemical treatments includes Thermal spraying,Plasma spraying.Ion implantation and deposition include Oxygen implantation, Nitrogen implantation,Carbon implantation and deposition, Metal ion implantation. Surface modification methods used to improve the mechanical, chemical and biological properties of titanium and its alloys for biomedical application. Keywords: Surface treatment, Osseointegration, Biomaterials, Microtopography, Biocompatibility.

Changes in the chemical compound and local atomic structure of ultrathin surface layers of Fe due to implantation of argon and oxygen ions

In this work, we consider the effect of irradiation in Ar+ → O+ and O+ → Ar+ sequences on changes in the chemical compound, type of chemical bond and the local atomic structure of ultrathin (~20 nm) iron surface layers. Investigation of the chemical compound and the type of chemical bond of the ion-modified surface was carried out by the XPS (X-ray photoelectron spectroscopy) and Auger electron spectroscopy. The study of changes in the local atomic structure was carried out by an XAFS-like method — electron energy loss fine structure (EELFS) spectroscopy. The parameters of the local atomic environment of oxygen and iron — partial interatomic distances, dispersion parameters, and coordination numbers — were obtained by analyzing atomic pair correlation functions. Analysis of experimental data showed that the two-stage irradiation of iron significantly changes the chemical compound and local atomic structure of the initial surface. This leads to formation of an oxide layer of greater depth than in the case of irradiation with only oxygen ions.

Constructing ultralong hollow chain-ball-like carbon nitride implanted with oxygen for superior visible-light photocatalytic hydrogen production

Regulating morphology has recently become an effective approach to improve the photocatalytic activity of graphite carbon nitride, but its morphology types are still limited. Herein, ultralong hollow chain-ball-like carbon nitride implanted with oxygen (OCNT) was prepared through a facile supramolecular self-assembly route. The ultralong hollow chain-ball-like structure results in enhanced photoinduced charge carrier separation. In particular, the implantation of oxygen into the chemical backbone leads to the formation of a midgap state, which can more effectively capture visible light. The H2 production rate (HPR) of OCNT is 5.47 mmol h−1 g−1, which is much higher than that of BCN by a factor of 14.0 under visible light irradiation. Moreover, BCN displays the very low HPR with values close to zero, while OCNT exhibits much superior efficiency (1.62 mmol h−1 g−1) under long visible light illumination (λ > 510 nm). The current research results may furnish fresh insights into the exploration of carbon nitride with different morphologies for high solar energy utilization.

Enhancing surface properties of (Fe,Cr)Al – Al2O3 nanocomposite by oxygen ion implantation

Ion implantation has been used as a surface treatment technique on (Fe,Cr)Al-10%vol Al2O3 nanocomposite to enhance its surface properties. The process was carried out at 150 kV with an oxygen dose of 1 × 1018 ions/cm2 at room temperature. Microstructural characterization and phase composition were performed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) of the Al2O3 layer formed on the nanocomposite surface. Mechanical properties measurements including hardness, fracture toughness and coefficient of friction were studied. Nanoindentation tests demonstrated an increase of 50% in the hardness value after ion implantation. Fracture toughness increased to a value of 21.3 ± 0.9 MPa m1/2 after O2 ion implantation. Scratch test results revealed an improvement in tribological behavior of the oxygen implanted surface compared to the un-implanted substrate. Cyclic oxidation tests, at 1100 °C, revealed that oxygen ion implantation slightly improved high temperature oxidation resistance of the nanocomposite.

Estimating the uncertainties of strain and damage analysis by X-ray diffraction in ion implanted MoO3

Ion implantation of oxygen in MoO3 lamellar crystals allows tuning their electrical conductivity by defect formation. X-ray diffraction (XRD) is a particularly sensitive technique to study such defects that cause changes in the lattice parameters and crystal quality. In this work, dynamical theory was applied to fit XRD patterns to obtain the strain and static Debye-Waller (DW) factor distributions as a function of depth. A two-step method was tested to estimate the uncertainties of these parameters within a certain region of interest. The limitations of the XRD characterization to study regions with low values of static DW factor are discussed.

Fabrication of Germanium-on-insulator in a Ge wafer with a crystalline Ge top layer and buried GeO2 layer by oxygen ion implantation

The paper reports fabrication of Germanium-on-Insulator (GeOI) wafer by Oxygen ion implantation of an undoped Ge wafer of orientation (100). O+ ions (energy 200 keV) were implanted to a fluence of 1.9 × 1018 ions-cm−2 and the implanted wafer was subjected to Rapid Thermal Annealing. The resulting wafer has a top crystalline Ge layer of ~ 220 nm thickness and resistivity ≈32 Ohm-cm and a buried Oxide layer (BOX) of crystalline GeO2 (thickness ≈0.62 μm). The crystalline GeO2 layer has hexagonal crystal structure with lattice constants close to the standard values. Raman Spectroscopy and cross-sectional electron microscopy established that the top Ge layer was recrystallized during annealing with a residual tensile strain of around +0.4% and an estimated dislocation density of 2.7 × 107cm−2. The crystallinity and electrical characteristics of the top layer and the quality of the BOX layer are such that it can be utilized for device fabrication.

Plasma-immersion ion implantation surface oxidation on a cobalt-chromium alloy for biomedical applications.

Co-Cr alloys such as L605 are widely applied for the manufacture of medical devices, including tiny cardiovascular stents. The presence of potentially toxic and allergenic release of Ni, Co, and Cr ions from these devices remains an unsolved concern. Surface modification by oxygen plasma immersion implantation (PIII) could be an excellent technique to create a dense and thin passive oxide layer on a relatively complex shape of a tiny device, such as a stent, thus reducing the potential release of metallic ions. The effect of oxygen PIII was investigated on L605 alloy specimens, from 5 to 50 mTorr gas pressures, and under pulsed bias voltages from -0.1 to -10 kV. The surface chemistry was investigated by x-ray photoelectron spectroscopy, while its morphology and surface energy were evaluated, respectively, by atomic force microscopy and scanning electron microscopy and by a sessile drop static contact angle. Electrochemical characterization was performed by potentiodynamic tests in the saline solution. Mechanical properties of the modified surface layer, specifically film adhesion and hardness (H), were assessed by scratch and nanoindentation tests. Results shown that the oxidized layers were composed of a mixture of Co and Cr oxides and hydroxides and were rich in Co. The corrosion rate was considerably reduced after O PIII, even for treatments using low bias voltage (-0.1 kV) and with consequent low oxygen implantation depth. Moreover, O PIII also improved surface hardness. The oxidized layers were found to have good adhesion and to be scratch resistant.

Sputter yield measurements to evaluate the target state during reactive magnetron sputtering

The sputter yield and discharge voltage of fourteen target materials (Al, Cr, Cu, Mg, Mo, Nb, Pb, Ta, Ti, V, W, Y, Zn, and Zr) have been measured during reactive sputtering in argon/oxygen mixtures. The obtained oxide sputter yields strongly differ from the published data based on ion beam experiments. A second observation is that based on the discharge voltage behavior observed during target oxidation, the materials can be subdivided into two groups. For the first group, the discharge voltage increases on the target oxidation, while for the second group the opposite behavior is observed. Both observations are explained based on a model that accounts for oxygen implantation into the target, preferential oxygen sputtering, and additional oxygen loss mechanisms such as outdiffusion. The difference between both groups can be explained from the oxygen fraction in the gas discharge required to fully oxidize the target surface. This required fraction is lower for the first group, and higher for the second group, than the oxygen fraction when the reactive sputter process switches into poisoned mode. The required fraction is mainly defined by the oxide sputter yield. The lower sputter yield as compared to literature values can be attributed to implanted oxygen that dilutes the formed oxide and/or continuously replaces sputtered oxygen.

Silicon Light-Emitting Diodes with Luminescence from (113) Defects

Silicon light-emitting diodes with luminescence associated with (113) defects are fabricated by the implantation of 350-keV oxygen ions at a dose of 3.7 × 1014 cm–2 and subsequent annealing at 700°C for 1 h in a chlorine-containing atmosphere. The electroluminescence is studied in wide temperature and excitation-power ranges. The line associated with the (113) defects is dominant in all the spectra. The temperature dependence of the line intensity depends on the excitation power at low temperatures: an increase in the intensity with an activation energy of 25 meV is observed at low current densities and no rise in the intensity is observed with increasing current density. At higher temperatures, an intensity with an activation energy of 59 meV is quenched irrespective of the current density. With increasing temperature, the peak of the line of the (113) defect shifts by the same energy as the energy-gap width, whereas the half width of the line grows linearly.

Oxygen-Ion Implantation into Cu50Ni50 Alloy: Effect on the Surface Composition and the Electrochemical and Corrosion Properties

The composition and certain properties of the surface layer produced by oxygen-ion implantation into the Cu50Ni50 alloy are studied. Oxygen-ion implantation is shown to result predominantly in the oxidation of nickel, which is the more electronegative component of the alloy. Different forms of nickel oxide are concentrated mainly on the alloy surface. These oxide layers enhance the propensity of the alloy to passivation and a decrease in anodic currents in alkaline media. The effect of oxygen-ion implantation on the behavior of the alloy in neutral and acidic media is less obvious. Oxygen-ion implantation enhances the electrochemical activity of the alloy toward the oxygen-reduction reaction.

Влияние имплантации ионов кислорода на физико-химическое строение и коррозионно-электрохимическое поведение высокохромистой стали

Potentiometry, atomic force microscopy, X-ray photoelectron spectroscopy, and microhardness measurements have been used to study the effect of oxygen ion implantation on the physicochemical structure of the surface and the corrosion-electrochemical behavior of high-chromium Fe-13Cr steel. It has been established that ion implantation leads to a significant reduction in material corrosion losses. Optimal from the point of view of surface passivation and, consequently, reduction of corrosion losses of the material is the regime of steel treatment with oxygen ions with a dose of D = 5·1016 cm–2 after which the sample demonstrates the most stable behavior during local and continuous corrosion. It is shown that the increase in the corrosion resistance of steel is due to the redistribution of elements in the surface layers of the samples caused by ion implantation and the intensive formation of spinels of variable composition, consisting of iron and chromium oxides with different oxidation states. In this case, the microhardness of the surface layers of the steel after ion implantation does not change significantly.

Влияние имплантации кислорода на коррозионно-электрохимическое поведение сплава медь-марганец

Влияние имплантации кислорода на коррозионно-электрохимическое поведение сплава медь-марганец

Critical-field slope reduction and upward curvature of the phase-transition lines of thin disordered superconducting [formula omitted] films in strong magnetic fields

We report the effect of disorder on superconducting phase transition of YBa2Cu3O7−x epitaxial thin films in external magnetic fields. The disorder was produced by several successive acts of oxygen ion implantation. Controlling a total accumulated dose of implanted ions nD, we carried out transport measurements in ab-plane for temperatures T below 91 K and external magnetic fields H up to 11 T. Temperature-field dependencies of in-plane resistivity allow us to analyze H−T phase diagrams for primary compound as well as for disordered structure. Considering the upper critical field Hc2 as the magnetic field which corresponds to a local resistivity drop at the onset of superconducting transition, we found out the following results. By gradual increasing of nD, the phase-transition line Hc2(T) suffers an unconventional critical-field slope reduction, while larger defect concentrations usually enhance the upper critical field in the vicinity of Tc0. Besides, for rather large nD, the curvature of Hc2(T) becomes upward for temperatures close to Tc0. Theoretical interpretation of the experimental data is developed in the framework of linearized Ginzburg-Landau theory with an inhomogeneous superconducting coherence length. A simple expression for the critical temperature Tc is obtained: Tc=Tc0(1−h+αh3/2), where h is the dimensionless magnetic field and α is a constant which describes the defects in a specimen. The formula nicely fits our experimental results.

Structural and optical characteristics investigations in oxygen ion implanted GaN epitaxial layers

This paper presents the lattice disorder-induced effect by oxygen ion implantation in GaN epitaxial layers. Oxygen ion implantation in GaN epitaxial layers is done with fluencies 5 × 1014 cm−2 and 5 × 1015 cm−2 at 120 keV energy on two different pieces of a GaN sample. Unimplanted and implanted GaN layers are investigated by High-resolution X-ray diffraction (HRXRD), Optical absorption and Raman spectroscopy. The in-plane and out of plane lattice parameters (i.e. a and c) of the distorted and undistorted region in the GaN samples are determined from the respective XRD peak positions. Due to the incorporation of oxygen ions in GaN layers up to implantation depth, lattice parameters are extended, as a result, the samples are under hydrostatic strain. Raman spectroscopic studies on the unimplanted and oxygen ion-implanted GaN samples are done by green and ultra-violet (UV) lasers. Raman spectroscopy results indicate that the broadening of the E2 (High) peak and intensity of A1 (LO) peak increases with increasing fluence. A doublet in A1 (LO) peak is found in UV excited Raman spectra in unimplanted and implanted GaN samples. The occurrence of the A1 (LO) doublet is due to surface defects and phonon-plasmon coupled-mode generated due to nonequilibrium photoexcited carriers. In this article, the origin of doublet has been studied and reported.