Cr Ion Implantation Research Articles

Spectroscopic ellipsometry modelling of Cr+ implanted copper oxide thin films

In this paper, we present modelling of spectroscopic ellipsometry data. The measured samples are thin films of copper oxides modified with the ion implantation method. The samples were prepared using reactive magnetron sputtering. Thin films of CuO and Cu4O3 were deposited and subjected to Cr ion implantation with an energy of 15 keV and a dose of 5 × 1016 ions/cm2. The decrease in crystallinity of the thin film as a result of the implantation was inspected with X-ray diffraction measurements. The implantation of Cr+ ions was simulated using the Stopping and Range of Ions in Matter software by Ziegler and Biersack. Ion beam energy of 15 keV was simulated to estimate the distribution of Cr ions in the copper oxides thin films. Optical parameters, such as refractive index, extinction coefficient, and absorption coefficient of the thin films, were investigated with spectroscopic ellipsometry. Multilayered models based on Tauc–Lorentz oscillators were developed for both oxides. Analysis of the optical properties showed that the ion implantation with Cr decreased the absorption of copper oxides thin films and the modelling proved that the material properties of top layers changed the most.

MD simulation study on the microstructural evolution of single-crystal Fe with pre-existing defects by Cr ion implantation

In this study, we present the molecular dynamics simulation of metal ion implantation, investigating the strengthening mechanism from a microstructural perspective. A single crystal Fe with pre-existing defects is constructed based on actual dislocation density and the effects of Cr ion implantation are investigated. Additionally, nanoindentation simulations are conducted to analyze the mechanical properties of workpieces with and without ion implantation. Effects of implantation energy and dose on the microstructure and hardness of workpieces are analyzed. The results indicate that (i) ion implantation introduces FeCr bonds with higher bond energy while reducing the original FeFe bond energy, (ii) increasing implantation energy and dose corresponds to a greater number of point defects and a higher amorphous structures proportion, (iii) the microstructure transformed by ion implantation promotes dislocation nucleation during nanoindentation, (iv) ion implantation enhances workpiece hardness due to the dual effects of interstitials impeding dislocation motion and the heightened mutual obstruction attributed to a higher dislocation density. Notably, the hardness initially enhances with increasing implantation energy and dose, followed by a slight decrease. The computational approach in this paper can serve as a valuable tool for studying the microstructural evolution of metal ion implantation by molecular dynamics simulations.

Influence of Cr Ion Implantation on Physical Properties of CuO Thin Films.

Cupric oxide is a semiconductor with applications in sensors, solar cells, and solar thermal absorbers. To improve its properties, the oxide was doped with a metallic element. No studies were previously performed on Cr-doping using the ion implantation technique. The research goal of these studies is to investigate how Cr ion implantation impacts the properties of the oxide thin films. CuO thin films were deposited using magnetron sputtering, and then chromium ions with different energies and doses were implanted. Structural, optical, and vibrational properties of the samples were studied using X-ray diffraction, X-ray reflectivity, infra-red spectroscopy, Raman spectroscopy, and spectrophotometry. The surface morphology and topography were studied with ellipsometry, atomic force microscopy, and scanning electron microscopy. A simulation of the range of ions in the materials was performed. Ion implantation had an impact on the properties of thin films that could be used to tailor the optical properties of the cupric oxide and possibly also its electrical properties. A study considering the influence of ion implantation on electrical properties is proposed as further research on ion-implanted CuO thin films.

Effect of Cr ion implantation on surface morphology, lattice deformation, nanomechanical and fatigue behavior of TC18 alloy

Cr ions with doses of 3.56, 5.53 and 7.12 × 1016 ions/cm2 were implanted on the TC18 alloy by ion implantation technique. Its effects on the surface morphology, lattice deformation, residual stress, nanomechanical and fatigue behavior were studied in detail. Results showed that irradiation damage and cascade collision during Cr implanted reduced the roughness of TC18 alloy, from the 114.61 nm to the minimum 36.74 nm at 5.5 × 1016 ions/cm2 dose. Surface XRD test indicated the diffraction peaks of TC18 alloy at 35.298°, 40.261° and 53.198° were obvious shifted after Cr ions implantation. The shifted direction and amplitude of diffraction peak was closely related to the implantation dose. The nanohardness and elasticity modulus of TC18 alloy first increased and then decreased with the increasing of implantation dose caused by solid solution strengthening and decreasing dislocation density. The fatigue life of TC18 after Cr ion implantation was slightly improved at high stress level (>460 MPa). When the stress level was lower than 460 MPa, it seemed that Cr ion implantation had little effect on the fatigue life of TC18 alloy.

Effects of single- and dual-element ion implantation on tribomechanical properties of Cronidur 30 bearing steel

This paper presents the results of a study on the effects of Ti ion and Ti + Cr ion implantation on the hardness and wear resistance of Cronidur 30 bearing steel. The mechanical properties of the samples implanted and nonimplanted were investigated by nanoindentation, friction and wear tests; The microstructures and phase transformations were also studied by grazing incidence X-ray diffraction (GIXRD) analysis, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The surface nanohardness improved significantly, changing from 11 GPa (non-implanted substrate) to 13 GPa (Ti ion sample) and 14 GPa (Ti + Cr ion sample). The increased wear resistance of Cronidur 30 after Ti + Cr ion implantation was twice that after Ti ion implantation and more than 10 times higher than that of the untreated sample. The TEM analysis confirmed the presence of amorphous and nanocrystalline phases in the samples. The XPS and GIXRD analyses confirmed new ceramic solutes. The tribomechanical improvement induced by implantation is attributed to the substructure strengthening and reinforcement of ceramic solutes.

Heavy doping of CdTe single crystals by Cr ion implantation

Abstract Implantation of bulk CdTe single crystals with high fluences of 500 keV Cr+ ions was performed to achieve Cr concentration above the equilibrium solubility limit of this element in CdTe lattice. The structure and composition of the implanted samples were studied using secondary ion mass spectrometry (SIMS), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS) to characterize the incorporation of chromium into the host lattice and to investigate irradiation-induced damage build-up. It was found that out-diffusion of Cr atoms and sputtering of the targets alter the depth distribution and limit concentration of the projectile ions in the as-implanted samples. Appearance of crystallographically oriented, metallic α-Cr nanoparticles inside CdTe matrix was found after implantation, as well as a strong disorder at the depth far beyond the projected range of the implanted ions.

Matrix effects on the relative sensitivity factors for manganese and chromium during ion microprobe analysis of carbonate: Implications for early Solar System chronology

The short-lived radionuclide 53Mn decays to 53Cr providing a relative chronometer for dating the formation of Mn-rich minerals in meteorites. Secondary ion mass spectrometry (SIMS) has been extensively used for in situ dating of meteoritic olivine and carbonate by the 53Mn–53Cr system, however a significant analytical challenge has been realising accurate measurements of the Mn/Cr ratio in individual minerals of differing chemical compositions. During SIMS analysis, elements are ionised with differing efficiencies and standard materials are required to calibrate measured ion intensities in terms of relative elemental concentrations. The carbonate system presents a particular analytical difficulty since such standards are not naturally available due to low and variable Cr contents. Here, we utilise ion implantation of Cr into carbonate and other phases to accurately determine the relative sensitivity factors of Mn/Cr during SIMS analysis. We find significant variations in Mn/Cr RSF values among different carbonate minerals that depend systematically on chemical composition and we propose an empirical correction scheme that quantitatively yields an accurate RSF for carbonates of diverse chemical compositions. Correction of SIMS carbonate data for this strong matrix effect may help to reconcile some outstanding problems regarding the timescales of aqueous alteration processes in carbonaceous chondrites. Mn–Cr ages, revised based our new understanding of the matrix effect, are, in general, earlier than previously thought and the duration of carbonate formation is shorter.

N and Cr ion implantation of natural ruby surfaces and their characterization

Energetic ions of N and Cr were used to implant the surfaces of natural rubies (low aesthetic quality). Surface colours of the specimens were found to change after ion implantation. The samples without and with ion implantation were characterized by diffuse reflectance spectra in ultra violet and visible region (DRS-UV–Vis), field emission scanning electron microscopy (FESEM), selected area electron diffraction (SAED) and nano-indentation. While the Cr-ion implantation produced deep red surface colour (pigeon eye red) in polished raw sample (without heat treatment), the N-ion implantation produced a mixed tone of dark blue, greenish blue and violet surface colour in the heat treated sample. In the case of heat treated sample at 3×1017N-ions/cm2 fluence, formation of colour centres (F+, F2, F2+ and F22+) by ion implantation process is attributed to explain the development of the modified surface colours. Certain degree of surface amorphization was observed to be associated with the above N-ion implantation.

Structure and magnetic properties of ZnO:Cr prepared by Cr ion implantation into ZnO crystals

ZnO:Cr layer was prepared by Cr ion implantation into ZnO bulk crystals. The structural, optical, and magnetic properties of the ZnO:Cr layer were studied with X-ray diffraction, photoluminescence, and superconductor quantum interferometer, respectively. The ZnO:Cr layer implanted Cr with a dose of 5×1016 cm−2 remained wurtzite structure and exhibited near-band-edge photoluminescence at 3.365 eV with full-width at half-maximum of 8.4 meV at 10 K. The magnetic measurement showed that the ferromagnetism changed at room temperature by different Cr concentration. For samples implanted to high doses, remanent magnetization reached 1.805×10−4 emu/g and coercive field was 244.5 Oe. Hall effect measurement showed a decrease of the resistivity from 251.7 cm Ω·cm to 28.6 ω · cm after annealing at 800 °c. The magnetism is interpreted by bound magnetic polarons, which were taken into account of the process that electrons were locally trapped by oxygen vacancies and occupied the orbitals that overlapped with d shell of neighboring Cr ions.

EELS and STEM analysis of metal nitride/substrate interfaces

Nitride based protective coatings produced by physical vapour deposition offer a promising means to extend the oxidation and wear performance of γ-TiAl. Metal ion pre-etching of the substrate surface has been shown to significantly enhance the adhesion between the coating and substrate. In this study we have applied spectroscopic imaging and advanced STEM analysis to study such interfaces. For a conventional Cr cathodic arc discharge Cr ion implantation of ~6nm into the substrate was observed. For an etch using high power impulse magnetron sputtering the metal ion implantation depth was reduced to ~2-3nm. In both cases a corresponding depletion zone of Ti and Al was observed. In addition, nitrogen diffusion into the substrate during coating deposition was also revealed to a similar depth respectively.

Fabrication of Discrete Track Media by Cr Ion Implantation

Discrete track media were successfully fabricated by Cr ion implantation. The saturation magnetization of the CoCrPt-SiO2 perpendicular recording layer was decreased down to 6% by implanting Cr ions with a dosage of 1 × 1017 ions/cm and an ion energy of 20 keV. A resist mask with a discrete track pattern was prepared by e-beam lithography and the pattern was transferred to the recording layer by Cr ion implantation. A clear magnetic contrast of the tracks was observed and the average surface roughness was maintained less than 1 nm. A clear servo signal was obtained by spin-stand measurement using a flying head. Feasibility of discrete track media fabrication by Cr ion implantation was confirmed.

Cr离子注入玻璃的太赫兹传输特性

Cr ion implantations in glass with the different doses of D=1.493x1017 and 4.976x1017 ion/cm2 are obtained by metal vapor vacuum arc (MEVVA). The effects of the different Cr ion implanted doses on terahertz (THz) transmission property are analyzed from THz time-domain spectroscopy. The results show that the more the Cr ion implanted dose in the micro-area implantation glasses, the larger the THz transmission except the larger absorption at 0.24 THz. This is an effect attributed to the coupling of plasmas on both the implantation and the implantation affected zones of the Cr ion implantation glass.

Effect of yttrium and chromium ion implantation on crevice electrochemical behavior of carbon steel in sodium chloride solution

In order to study the effect of yttrium (Y) and chromium (Cr) ion implantation on the crevice corrosion behavior of carbon steel, the carbon steel was implanted with Y and Cr ion using MEVVA source at an energy of 40 keV. Electrochemical measurement was employed to evaluate the crevice corrosion of implanted carbon steel in NaCl solution. The results indicated that, after Y and Cr ion implantation, the carbon steel's crevice corrosion resistance and electrochemical characteristic were significantly improved in NaCl solution when the implantation dose of Y increased. Auger electron spectroscopy (AES) analysis of the implanted carbon steel manifested that the surface layer was mainly composed of elements Fe, Cr, O, and Y. Most of element Y was located near the outside region of the surface layer/solution interface, whereas Cr was enriched in the transition area between surface layer and matrix. By X-ray photoelectron spectroscopy (XPS) analysis, the implanted Y was in the form of Y 2O 3, whereas Cr in the form of Cr 2O 3 in the surface layer. The mechanism of the crevice corrosion resistance and electrochemical characteristic improvement was that, after Y and Cr ion implantation, the surface layer seemed to be constituted by Y 2O 3 and Cr 2O 3. The surface layer acted as a barrier to reduce the metal matrix to contact with the corrosion medium such as inhibiting Cl − ions from corroding the layer.

Electrochemical behaviour of chromium-implanted magnesium in hydroxide, chloride and sulphate solutions

Despite the development and subsequent improvement of new Mg-based alloys, their vulnerability to oxidation and corrosion continues to pose a major obstacle to their more generalized use. The possibility of blocking high diffusivity paths, such as grain boundaries, by ion implantation may help to improve their oxidation and corrosion resistance, because mass transport through these short circuiting paths is reduced. Electrochemical techniques were used to investigate the effect of Cr ion implantation in the electrochemical behaviour of Mg in aqueous solutions. In particular ion implanted fluences of 5 × 10 16 and 5 × 10 17 at./cm 2 have been evaluated in solutions of NaCl, NaOH and Na 2SO 4. The corroded surfaces and products were analysed by ion beam analysis, scanning electron microscopy and X-ray diffraction. A model of the corrosion mechanism is proposed to explain the obtained results.

Photocatalytic decolorization of anthraquinonic dye by TiO2 thin film under UVA and visible-light irradiation

Abstract In this investigation, the effectiveness of using photocatalytic sol–gel TiO 2 thin film to decolorize anthraquinonic dye Acid Blue 80 was evaluated experimentally. The TiO 2 photocatalysts synthesized were characterized by DSC–TG, XRD, HRTEM, UV–vis spectra, SEM, and XPS. The experimental results showed that a TiO 2 thin film formed without high temperature calcination could effectively perform photocatalytic decolorization under UVA irradiation. After the TiO 2 thin film was modified by Cr ion implantation, the characterization by UV–vis spectra showed that the light absorption was extended beyond UV to the visible range. The modified thin film could perform visible-light-assisted photocatalytic decolorization of the dye. The overall study demonstrates the promise of solar photocatalytic decolorization of dye for treatment of textile effluent. By adopting immobilized TiO 2 thin films instead of conventional suspended TiO 2 particles, the photocatalytic water treatment method becomes more cost-effective as the costly filtration process, normally needed to recover TiO 2 particles from the effluent discharge, can be omitted.

New Silicon-Based Materials for Spintronics Applications - Si:V and Si:Cr

We present here two new silicon-based materials for possible applications as spintronics materials. These materials are based on high dose ion implantation of transition metal ions, V+ or Cr+ into a single crystalline silicon wafer. After ion implantation, thermal anneals at high temperatures and high hydrostatic pressures are carried out in a high pressure chamber. Secondary ion mass spectrometry is used to characterize the re-distribution of the implanted atoms after thermal anneals; photoluminescence and X-ray techniques are applied to check microstructure of the samples. A variable temperature SQUID magnetometer is used to measure the magnetic properties of the processed samples. It is found that some of the samples showed ferromagnetic hysteresis loops at low temperatures. Implications of our findings are discussed in terms of future applications of spintronics materials based on ion-implanted silicon.

Cr ion implantation into Ti: Part I. Formation of intermetallic Laves phase

High fluence implantations of chromium ions were used to promote the formation of Ti–Cr compounds in the surface region of pure titanium. The implanted samples were characterized by Rutherford Backscattering Spectroscopy (RBS), Particle Induced X-ray Emission (PIXE), and Grazing Incidence X-ray Diffraction (GIXRD), revealing different types of Ti–Cr alloys, which include the intermetallic Laves phase TiCr 2. Implantation temperature is presented as a key factor necessary to achieve different Ti–Cr surface compounds directly by ion implantation without the need of further treatments. It is also shown that temporal coincidence between ion implantation and heat delivery is essential to intermetallic phase formation since ion implantations performed at room temperature and followed by thermal annealing treatments do not lead to similar results.

Magnetic and optical properties of Cr +-implanted GaN

In this paper, we report the fabrication of ferromagnetic semiconductor on GaN substrates by high-dose Cr ion implantation. Both magnetic and optical properties for Cr +-implanted GaN were studied by photoluminescence and superconducting quantum interference device. The results of photoluminescence reveal that the implanted chromium incorporates substitutionally on Ga site and forms deep acceptor level in GaN. The materials show ferromagnetic-like order up to 300 K as indicated by temperature-dependent magnetization measurement. The M vs. T curve also implies the presence of different components to the magnetization in Cr +-implanted GaN.

Low-temperature metal ion implantation assisted deposition of hard coatings

Wear-resistant coatings were deposited by using a vacuum arc ion plating technique combined with pulsed plasma surface treatment. By combining the pulsed processes of the bias voltage as well as of a metal plasma ion implantation (MPII), the substrate temperature was kept below 160 °C. The metal vapor vacuum arc (MeVVA) ion source used was equipped with a Cr cathode, a low-frequency ignition system and high voltage supplies for the ion acceleration and plasma shielding, respectively. Mechanical properties of the coatings like thickness, hardness and adhesion were clearly influenced by the metal ion bombardment before and during the deposition process. This will be shown for TiN-coated cemented carbide tools modified by Cr ion implantation with an ion acceleration voltage varied up to 40 kV. The findings of nanoindentation measurements are consistent with the results of X-ray stress analysis (XSA) investigations. The effect of the metal ion implantation process into the surface region of the carbide tools and the growing coatings on the tool lifetime will be discussed.

Ferromagnetic AlGaCrP Films by Ion Implantation

Ion implantation of Cr at concentrations of 3 and 5 atom % was performed in Al x Ga 1 - x P:C (x = 0,0.24,0.38) epi layers grown by gas source molecular beam epitaxy. No second phases were detected by both X-ray diffractionand transmission electron microscopy. Ferromagnetic ordering to 300 K was observed in superconducting quantum interference device (SQUID) measurements, comparable to similar samples using Mn as the dopant. As well, calculated saturation moments are found to lower for Cr-implanted materials than Mn-implanted materials. As the Al fraction in the ternary starting material is increased, the saturation moments are found to decrease. Based upon this evidence, Cr does not appear to be an advantageous choice compared to Mn for high-temperature ferromagnetism in AlGaP.