Oxygen Implantation Research Articles

Low-Loss Optical Waveguides Preserving Photoluminescence Features in Pr3+-Doped Yttrium Orthosilicate Crystal Fabricated by Ion Implantation

Low-loss planar and channel waveguides in ${\rm Pr}^{3+}$ -doped yttrium orthosilicate single crystals were fabricated using 6-MeV oxygen ion implantation. The fabricated surface guiding structure was characterized by the prism coupling method. The relationship between the implantation induced index change and the implantation fluence has been investigated. The photoluminescence properties of the implanted samples were found to be well preserved with respect to the bulk, exhibiting possible applications for integrated quantum memory and laser generation devices.

INFLUENCE OF SILICON LAYER PROPERTIES ON CAPACITANCE PARAMETERS OF MIS/SOS-STRUCTURES

The influence of the epitaxial layer features and so silicon-sapphire interface in SOS-structures on capacitance parameters of MIS-structures formed on SOS with submicron silicon layers were investigated in this article. Both standard SOS-structures with 0.3 μk silicon n-type layer and analog SOS-structures with the blastic silicon layer amorphizated by the oxygen ion implantation with following high-temperature annealing. The two different types of test MIS-structures with 30 nm gate oxide, polysilicon gate and metallic contacts were fabricated. The strong difference in the capacitance characteristics for standard SOS and SOS with recrystallization silicon layer was disclosed in depletion region. It was revealed the strong frequency dependence of capacitance characteristics for the test MIS-structures formed on almost all SOS-structures. It was shown that the character of the test structures C — V -curves were defined by dimension and configuration of the silicon layer as well as the deep compensate levels concentration in layer near silicon-sapphire interface. Particularly it was shown that big changes of the frequency-capacitance dependences at transition from the tests formed on standard SOS to tests on SOS with blastic silicon layer were determined by great concentration of deep compensate centers in layer near interface for standard SOS. It was shown that the recrystallization of silicon layer by oxygen ion implantation may lead to appearance of the centers, formed donor levels into silicon band gap and appearance of the frequency-capacitance dependences in depletion region of such SOS-structures.

Oxygen reduction by plasma cleaning in low-energy ion implantation of silver ions in titanium

In this study silver ions were implanted on titanium surface through the technique of ion implantation at low energy in a device called Ion Plating Diversified. The titanium reacts easily at room temperature forming a thin oxide layer on its surface. Which may reduce the efficiency of the process, damaging it not only by forming a barrier to implementation but also by the reaction of oxygen with silver, nullifying its bactericidal effect. To reduce the oxygen effect, a strategy was elaborated for surface cleaning to remove of this oxide prior to ion implantation. To verify the effectiveness of implantation and qualitative reduction of oxygen to physical-chemical characterization samples were evaluated. The results show that silver is actually implanted on the surface of titanium, a few nanometers in depth, as well as a qualitative reduction of oxygen on the surface. Comparing the different types of treatment it was found that the plasma cleaning can be applied prior to the implantation process, proving effective in reducing the oxygen, and also because it is a non-polluting technique. http://dx.doi.org/10.18226/23185279.v3iss1p12

Structural and electrical properties of oxygen complexes in Cz and FZ silicon crystals implanted with carbon ions.

PACS34.50.Dy; 61.10.-i; 68.35.DvElectronic supplementary materialThe online version of this article (doi:10.1186/1556-276X-9-693) contains supplementary material, which is available to authorized users.

Low oxygen tension increase mitochondrial membrane potential and implantation ability by enhanced expression of antioxidant genes in mouse blastocyst cultured in vitro

In human IVF, many studies have shown that embryos cultured in lower oxygen tension (5% O2) have higher pregnancy rate, when compared with normaxic condition (20% O2). However the beneficial effect of low oxygen tension in embryogenesis remains unclear. This study aimed to investigate the expression of oxygen and antioxidant genes in mouse embryo cultured under hypoxic and normaxic conditions.

A study on the effect of oxygen implants in CuInSe2 by photoacoustic spectroscopy

This paper presents the results of an analysis on defect states changes following the irradiation of oxygen in CuInSe2 single crystals by using photoacoustic spectroscopy. CuInSe2 samples, n‐type conducting, of high quality grown by using the vertical Bridgman technique have been implanted at ambient temperature with O+ with the energy of 40 keV with doses of 1015 and 1016 ions/cm2. A theoretical model based on two‐layer samples has been used to extract the absorption spectrum of only the implanted layer from that of the bulk. Oxygen is found to create a shallow defect at 31meV and a deep one at 256±2 meV. It has also led to the disappearance of some other defect levels originally detected in the samples prior to implantation.

Magnetic properties of Gd‐doped GaN

In this paper, we discuss the magnetic properties of Gd‐doped GaN. This diluted magnetic semiconductor shows hysteretic magnetization behavior at room temperature, which is attributed to ferromagnetism with a Curie temperature well above 300 K. However, the experimental results regarding the magnetic properties are not completely consistent and the microscopic origin for the reported magnetic properties is still unclear. We discuss the role of the growth method of the GaN comparing molecular beam epitaxy (MBE) and metal organic chemical vapor deposition (MOCVD) including GaN doped during the growth process with Gd as well as Gd‐implanted material. It seems that in general it is easier to obtain hysteretic magnetization behavior for MBE‐grown material probably due to the higher oxygen and lower hydrogen content. An exception is Gd‐implanted GaN MBE‐grown on Si(111) where we observe no ferromagnetism. We will present experiments where by oxygen implantation and annealing the impurity concentration was manipulated. The role of native defects is addressed and new experiments where additional defects have been introduced by nitrogen implantation in MBE‐grown GaN:Gd are discussed. We present our results on anomalous Hall effect observed in a Gd‐implanted GaN/AlGaN heterostructure.

Tuning the ferromagnetic-antiferromagnetic interfaces of granular Co-CoO exchange bias systems by annealing

The low-temperature magnetic behavior of granular Co-CoO exchange bias systems, prepared by oxygen ion implantation in Co thin films and subsequent annealing, is addressed. The thermal activation effects lead to an O migration which results in virtually pure Co areas embedded in a structurally relaxed and nearly stoichiometric CoO phase. This yields decreased training and exchange bias shifts, while the blocking temperature significantly increases, coming close to the Néel temperature of bulk CoO for samples implanted to a fluence above 1 × 1017 ions/cm2 (15% O). The dependence of the exchange bias shift on the pristine O-implanted content is analogous to that of the antiferromagnetic thickness in most ferromagnetic/antiferromagnetic systems (i.e., an increase in the exchange bias shift up to a maximum followed by a decrease until a steady state is reached), suggesting that, after annealing, the enriched Co areas might be rather similar in size for samples implanted above 1 × 1017 ions/cm2, whereas the corresponding CoO counterparts become enlarged with pristine O content (i.e., effect of the antiferromagnet size). This study demonstrates that the magnetic properties of granular Co-CoO systems can be tailored by controllably modifying the local microstructure through annealing treatments.

Oxygen-implanted optical planar waveguides in Er3+/Yb3+-codoped silicate glasses for integrated laser generation

Er 3+ /Yb 3+ -codoped silicate glasses are good candidates for the application of laser actions and signal amplification. Optical planar waveguides in Er 3+ /Yb 3+ -codoped silicate glasses are fabricated by 6.0-MeV oxygen-ion implantation with a dose of 6.0×10 14 ions/cm 2 at room temperature. The SRIM 2010 code is carried out to simulate the energy losses during the implantation process in order to obtain a better understanding of the waveguide formation. The guiding modes and near-field intensity distributions of the waveguide are characterized by the prism-coupling and end-face coupling methods. The refractive index profile and light propagation mode of the planar waveguide are numerically calculated by the reflectivity calculation method and finite difference beam propagation method. The waveguide has a “well+barrier ” refractive index distribution and its optical loss is ∼1.02 dB/cm . The microluminescence and absorption investigation reveal that fluorescent and transmission properties in the waveguide are well preserved with respect to the bulk, suggesting promising potential for waveguide amplifiers and lasers.

Ion beam induced single phase nanocrystalline TiO2 formation

Single phase TiO2 nanostructures are fabricated by oxygen ion implantation (60keV) at fluence ranging from 1×1016 ions/cm2 to 1×1017 ions/cm2 in titanium thin films deposited on fused silica substrate and subsequent thermal annealing in argon atmosphere. GAXRD and Raman spectroscopy study reveals formation of single rutile phases of TiO2. Particle size is found to vary from 29nm to 35nm, establishing nanostructure formation. Nanostructure formation is also confirmed by the quantum confinement effect manifested by the blueshift of the UV–vis absorption spectra. Photoluminescence spectra show peaks corresponding to TiO2 rutile phase and reveal the presence of oxygen defects due to implantation. The controlled synthesis of single phase nanostructure is attributed to ion induced defects and post-implantation annealing. It is observed that the size of the nanostructures formed is strongly dependent on the ion fluence.

The microstructural and electrochemical properties of oxygen ion implanted nanocrystalline diamond films

The nanocrystalline diamond (NCD) films are implanted by oxygen ions with a dose of 1×1012 cm-2 and subsequently annealed at 700, 800, 900 and 1000 ℃, respectively. The microstructure and electrochemical properties of these NCD films are investigated systematically and the results show that the potential windows of the unannealed sample (O120) and 1000 ℃ annealed sample (O121000) increase up to 4.6 V and 3.61 V, respectively. The mass transfer efficiencies of the two samples are also better, indicating that the oxygen ion implantation and 1000 ℃ annealing can improve the mass transfer efficiency of NCD film. The results of infrared spectrum measurements show that there are no hydrogen atoms that are terminated to the surfaces of samples O120 and O121000, while hydrogen atoms terminate to the surfaces of the other samples. It is indicated that oxygen ion implantation and 1000 ℃ annealing can damage hydrogen terminations in the surface, which improves the electrochemical performances of NCD films. Raman spectrum measurements suggest that high content of diamond phase, small internal stress and more disordered amorphous carbon can improve the electrochemical properties of NCD films. When the number or size of sp2 carbon clusters in amorphous carbon grain boundaries decreases, the electrochemical properties of NCD films become better.

Effect of oxygen implantation on microstructural and optical properties of ZnTe:O intermediate-band photovoltaic materials

Group Ⅱ-VI and Ⅲ-V highly mismatched alloys are promising material systems in the application of high efficiency intermediate-band solar cell (IBSC), however, the key issues including band engineering of intermediate band still remain challenging. In this study, ZnTe:O alloys have been produced by isoelectric oxygen implantation into ZnTe single crystal, and the influences of implantation on the microstructural and optical properties of ZnTe:O have been investigated in detail. It is found that a proper dose of oxygen ions can lead to a compressive strain in the lattice and induce the formation of intermediate band located on the energy level of ～ 0.45 eV below the conduction band. While a high dose of oxygen ions causes ZnTe surface layer to become amorphous and enhances the deep level emission around 1.6 eV, which is related to Zn vacancies. Results of resonant Raman and time-resolved photoluminescence spectra indicate that implantation induced intermediate band is related to the localized exciton emission bound to oxygen isoelectric trap, and the associated photo excited carriers have a relatively long decay time. This suggests that the reduction of lattice distortion and alloy disorder may be needed for converting localized states of the intermediate band into extended states, which is crucial to realize high efficiency ZnTe:O based IBSCs.

Surface modification and corrosion properties of implanted and DLC coated stainless steel by plasma based ion implantation and deposition

The aim of this investigation was to find a suitable pretreatment for the subsequent deposition of DLC films on a steel substrate. The implantation should on the one hand improve the corrosion properties of the steel substrate and on the other hand increase the adhesion of the DLC film to the substrate. Three different gases (oxygen, nitrogen, ethylene) were used for the implantation (voltage pulses of −10kV), and the deposition (−15kV) was performed with C2H4 on stainless steel substrates and silicon wafer by plasma based ion implantation and deposition (PBII&D).The influence of the different implantation gases on the composition, structure and corrosion resistance of the surface was studied. The surface morphology was changed depending on the working gas. In all implantation samples a composition gradient layer in the surface was confirmed by measurement of the depth distribution by SIMS and XPS. The DLC films as prepared with C2H4 PBII&D exhibited roughness, hardness, and friction properties similar to those of DLC films prepared by other hydrocarbon gases.The corrosion protection potential in an aqueous environment was evaluated by cyclic voltammetry. The oxygen and nitrogen implantations improved the corrosion protection properties. These two pretreatments also exhibited a good corrosion protection in combination with the DLC film coatings. This is due to the resulting bonding states in the implanted surface and due to an increased adhesion of the DLC films to the substrates as could be seen after the corrosion tests.

Enhanced antimicrobial properties, cytocompatibility, and corrosion resistance of plasma-modified biodegradable magnesium alloys

Magnesium alloys are potential biodegradable materials and have received increasing attention due to their outstanding biological performance and mechanical properties. However, rapid degradation in the physiological environment and potential toxicity limit clinical applications. Recently, special magnesium–calcium (Mg–Ca) and magnesium–strontium (Mg–Sr) alloys with biocompatible chemical compositions have been reported, but the rapid degradation still does not meet clinical requirements. In order to improve the corrosion resistance, a rough, hydrophobic and ZrO2-containing surface film is fabricated on Mg–Ca and Mg–Sr alloys by dual zirconium and oxygen ion implantation. Weight loss measurements and electrochemical corrosion tests show that the corrosion rate of the Mg–Ca and Mg–Sr alloys is reduced appreciably after surface treatment. A systematic investigation of the in vitro cellular response and antibacterial capability of the modified binary magnesium alloys is performed. The amounts of adherent bacteria on the Zr–O-implanted and Zr-implanted samples diminish remarkably compared to the unimplanted control. In addition, significantly enhanced cell adhesion and proliferation are observed from the Zr–O-implanted sample. The results suggest that dual zirconium and oxygen ion implantation, which effectively enhances the corrosion resistance, in vitro biocompatibility and antimicrobial properties of Mg–Ca and Mg–Sr alloys, provides a simple and practical means to expedite clinical acceptance of biodegradable magnesium alloys.

Effects of chromium ion implantation voltage on the corrosion resistance and cytocompatibility of dual chromium and oxygen plasma-ion-implanted biodegradable magnesium

Magnesium is modified by chromium ion implantation at different voltages followed by oxygen ion implantation to improve the corrosion resistance and cytocompatibility. All the implanted samples exhibit improved corrosion resistance and the ones implanted at a lower voltage yield better results. The chromium-rich layer with chromium in the metallic state beneath the protective oxide film may undermine the electrochemical stability by inducing galvanic effects which lead to poorer corrosion resistance. Although dual Cr–O plasma immersion ion implantation promotes osteoblast adhesion and proliferation on the magnesium samples and produces a more favorable environment for osteoblast growth, optimal results require careful selection of the ion implantation voltage.

Oxygen Ion Implantation Enhanced Silicon-Vacancy Photoluminescence and n-Type Conductivity of Ultrananocrystalline Diamond Films

We report the enhanced silicon-vacancy (Si-V) photoluminescence (PL) intensity and n-type conductivity of ultrananocrystalline diamond (UNCD) films by oxygen ion (O+) implantation. With O+ dose increasing from 1014 to 1015 cm−2, the PL intensity and n-type conductivity significantly increase by 6 and 45 times, respectively, after 1000°C annealing. The secondary ion mass spectroscopy mapping measurements show that the content of oxygen is larger in the zone, which has larger content of silicon, indicating that oxygen tends to adhere to silicon. It is suggested that oxygen related Si-V defects are formed, which will enhance the PL intensity and n-type conductivity of UNCD films.

Wear and corrosion behavior of oxygen implanted biomedical titanium alloy Ti–13Nb–13Zr

Titanium alloy Ti–13Nb–13Zr was implanted with oxygen ions by plasma immersion ion implantation. The influence of oxygen ion implantation on the growth of apatite on the implanted sample was investigated by immersion in Hanks’ solution and also by potentiodynamic polarization studies in Hanks’ solution. XRD shows the formation of mainly anatase form of oxide. FESEM images of immersion tested samples show that growth of apatite is more with larger sized deposits on oxygen implanted surface as compared to that on the untreated substrate. XPS investigation of corrosion tested and 1 day immersed samples show higher amount of calcium, phosphorous and oxygen in hydroxide/phosphate form on the oxygen implanted sample. EDS results also confirm higher concentration of Ca and P on oxygen implanted sample. Polarization and electrochemical impedance spectroscopy studies show that the oxygen implanted layer behaves like a nearly ideal capacitor with better passivation characteristics. In sliding wear studies, the implanted layers displayed a lower friction coefficient as compared to the substrate one.

Improving the Magnetic Properties of Co–CoO Systems by Designed Oxygen Implantation Profiles

Oxygen implantation in ferromagnetic Co thin films is shown to be an advantageous route to improving the magnetic properties of Co-CoO systems by forming multiple nanoscaled ferromagnetic/antiferromagnetic interfaces homogeneously distributed throughout the layer. By properly designing the implantation conditions (energy and fluence) and the structure of the films (capping, buffer, and Co layer thickness), relatively uniform O profiles across the Co layer can be achieved using a single-energy ion implantation approach. This optimized configuration results in enhanced exchange bias loop shifts, improved loop homogeneity, increased blocking temperature, reduced relative training effects and increased retained remanence in the trained state with respect to both Co/CoO bilayers and O-implanted Co films with a Gaussian-like O depth profile. This underlines the great potential of ion implantation to tailor the magnetic properties by controllably modifying the local microstructure through tailored implantation profiles.

Improvement of surface properties of AISI 316L SS by oxygen and helium ion implantation

PurposeThe purpose of the paper is to study effect of the implantation of oxygen and helium ions on the corrosion performance of the AISI3l6L stainless steel. It presents useful new results which allows one to draw conclusions as to the suitability of the helium and oxygen ion implanted AISI 316L stainless steel for biomedical use in the body.Design/methodology/approachThe implantation of oxygen and helium ions was done on AISI 316L SS at an energy level of 100 keV at a dose of 1×1017 ions/cm2, at room temperature. In order to simulate the natural tissue environment, an electrochemical test using cyclic polarization was done in a 0.9 percent sodium chloride solution at a pH value of 6.3 at 37°C. This was carried out on both the virgin and implanted AISI 316L stainless steel for the purpose of comparing performance. In addition to this, the hardness of the virgin and implanted samples was also studied using Vickers microhardness tester with varying loads. Besides, the surface morphologies of the implanted samples and the corroded samples were studied with XRD and SEM.FindingsFrom the study the following findings are made. First, the XRD and SEM results were found to be in accordance with the corrosion test results. Second, the general corrosion behavior showed a significant improvement in the case of both helium implanted (icorr=0.0689 mA/cm2) and oxygen implanted (icorr=1.104 mA/cm2), when compared to the virgin AISI 316L SS (icorr=1.2187 mA/cm2). The pitting corrosion showed a significant improvement for helium implanted (Epit=230 mV) when compared to virgin material (Epit=92 mV). The oxygen implanted has not shown any improvement (Epit=92 mV). The surface hardness is found to be 1202 HV for helium implanted and 1020 HV for oxygen implanted, while it is found to be 195 HV for the virgin material. The hardness of the helium and oxygen implanted samples is found to be increased by about 600 percent and 500 percent, respectively, when compared to the virgin samples. Helium implanted samples show better performance in terms of corrosion resistance and hardness when compared to those of the oxygen implanted samples.Originality/valueAlthough a number of authors have conducted many research on AISI 316L stainless steel, this work has original experimental results in terms of the oxygen and helium ion implantation parameters used and the specific tests: microhardness, electrochemical corrosion test, SEM and XRD that were used. It thus presents useful new results which allows one to draw conclusions as to the suitability of the Helium and Oxygen ion implanted AISI 316L stainless steel for biomedical use.

Quantitative depth-resolved photoelectron spectroscopy analysis of the interaction of energetic oxygen ions with the beryllium–tungsten alloy Be2W

Abstract The chemical reactions during the implantation of oxygen ions into a thin beryllium–tungsten alloy layer on a beryllium substrate and subsequent annealing are investigated by depth-resolved chemical analysis using X-ray photoelectron spectroscopy. By using variable photon energies at a synchrotron, identical kinetic energies of the photoelectrons from the different core levels are selected. This enables a chemical analysis at identical depth intervals for all core levels. From these sets of photoelectron spectra chemically resolved depth profiles are determined. The depth profiles allow an interpretation of the reaction and diffusion steps during implantation and annealing steps. This leads to a detailed understanding of the complex processes in a multi-component solid.