Oxygen Ion Implantation into Indium Phosphate

This paper is the results of oxygen ion implantation on morphological and electrical properties of indium phosphate (InP) semiconductor wafers. The oxygen ions were implanted at 30 keV and various doses in the range between 5 × 10¹⁵ and 5 × 10¹⁷ ions/cm² and at nearly room temperature. The changes in surface roughness and resistivity before and after the implantation is studied using atomic force microscopy (AFM) and four-point probes technique, respectively. The results show that the resistivity is depend on the ion implantation dose. In addition, the RMS roughness of implanted samples dramatically increases by accumulation of oxygen ion dose.     

Microstructure and Surface Properties of Silver after High Dose Nitrogen Ion Implantation

In this paper the effect of nitrogen ion implantation at the energy of 50 keV and doses in the range between 10¹⁷ and 2 × 10¹⁸ ions/cm² on silver surface has been discussed. X-ray diffraction (XRD) analysis was used to characterize microstructure of implanted layer. The XRD results confirmed that by such implantation AgN₃ has been produced. Silver trinitride with orthorhombic structure was formed on cubic structure of silver surface. RMS roughness of implanted samples have been obtained using atomic force microscopy (AFM) analysis and compared with un-implanted sample. Microhardness properties of implanted samples measured by Vickers test. The results show that by increasing the ion dose up to 1 × 10¹⁸ ions/cm² hardness enhances. Finally, reflection changes at the UV–Vis-NIR region measured by diffuse reflectance accessory of a spectrophotometer. The results of spectrophotometry analysis show reduction in diffused reflection spectrum of nitrogen implanted samples.     

Corrosion Resistance Modification of AISI 304 Stainless Steel Using Argon Ion Bombardment

Ion implantation has been widely used as a surface modification technique to improve surface properties. In this work, argon ions of 30 keV energy have been implanted into AISI 304 stainless steel at different fluences ranging from 3 × 10¹⁷ to 1 × 10¹⁸ Ar⁺/cm². The surface bombardment with inert gases mainly produces structural changes and modify topography and morphology of the surface. The AFM analysis of implanted samples clearly shows significant change in surface. In order to evaluate the effect of the ion bombardment on the corrosion behavior, potentiodynamic tests were performed. The results show that the corrosion resistance of the samples strongly depends on the implantation fluences.     

Pitting and EPR studies of ion implanted plain and sensitized 304 stainless steel

30 keV N₂⁺, Ti⁺ and N₂⁺ followed by Ti⁺ ions were implanted at room temperature on plain and sensitized 304 stainless steel (304 SS) foils. The ion fluences ranged from 1 × 10¹⁷ ions/cm² to 5 × 10¹⁷ ions/cm². Pitting studies in quiescent non-dearated 3.5 wt.% NaCl electrolyte and Electrolytic Potentiokinetic Reactivation (EPR) studies in a standard electrolyte of KSCN + H₂SO₄ were carried out on plain, sensitized and implanted plain, and sensitized 304 SS foils. In general, the localized corrosion behaviour deteriorated on implantation in plain 304 SS irrespective of the nature of the implant species and their fluences employed in this work. However, the localized corrosion behaviour of implanted sensitized 304 SS showed an improvement. The benefits accrued was dependent on the nature of the implant species and their fluences. An attempt has been made to explain why the implant species interact differently, with the consequent difference in the localized corrosion behaviour, when the stainless steel substrate is in the sensitized state.     

Microstructural investigation of alumina implanted with 30 keV nitrogen ions

Among ceramics, alumina is being widely used as biomaterials now these days. It is being used as hip joints, tooth roots etc. Ion implantation has been employed to modify its surface without changing it bulk properties. 30 keV nitrogen with varying ion dose ranging from 5 × 10¹⁵ ions/cm² to 5 × 10¹⁷ ions/cm² is implanted in alumina. Surface morphology has been studied with optical microscope and atomic force microscope (AFM). Improvement in brittleness has been observed with the increase in ion dose. Compound formation and changes in grain size have been studied using X-Ray diffraction (XRD). AlN compound formation is also observed by Fourier transform infrared spectroscopy (FTIR). The change in the grain size is related with the nanohardness and Hall-Petch relationship is verified.     

Nanopatterning of silica with mask-assisted ion implantation

In the present paper we combined ion implantation and nanosphere lithography to regularly dope, by a mask-assisted process, a SiO₂ substrate with rare earth ions (Er) by ion implantation and to fabricate by sputtering a plasmonic 2D periodic array of Au nanostructures on the silica surface spatially coupled to the implanted Er³⁺ ions. The aim of this work is to study how Er³⁺ emission at 1.5 μm can be affected by the interaction with a plasmonic nanostructure. In particular we have found a variation of the radiative lifetime of the Er³⁺ emission and a change from single exponential to bi-exponential of the luminescence intensity decay.     

High yield antibiotic producing mutants of Streptomyces erythreus induced by low energy ion implantation

Conidia of Streptomyces erythreus, an industrial microbe, were implanted by nitrogen ions with energy of 40–60 keV and fluence from 1 × 10¹¹ to 5 × 10¹⁴ ions/cm². The logarithm value of survival fraction had good linear relationship with the logarithm value of fluence. Some mutants with a high yield of erythromycin were induced by ion implantation. The yield increment was correlated with the implantation fluence. Compared with the mutation results induced by ultraviolet rays, mutation effects of ion implantation were obvious having higher increasing erythromycin potency and wider mutation spectrum. The spores of Bacillus subtilis were implanted by arsenic ions with energy of 100 keV. The distribution of implanted ions was measured by Rutherford Backscattering Spectrometry (RBS) and calculated in theory. The mechanism of mutation induced by ion implantation was discussed.     

Energy loss and straggling of Li ions in the polymer foils

Energy loss and straggling of 0.18-0.78 MeV/amu ⁷Li ions in polycarbonate, polyethylene terephthalate and polypropylene foils were measured by means of a transmission technique with a half-covered detector. The stopping force measurements are compared with the SRIM 2006 calculation and the database of the ICRU report 73. The measured energy loss straggling are in satisfactory agreement with the results yielded using the empirical formula at the higher energy region. The obtained data also demonstrated that the validity of Bragg’s rule applied to stopping force and energy loss straggling for ⁷Li ions in polymer foils.     

Surface exfoliation and defect structures in Si induced by 160 keV He and 110 keV H ion implantation

Cz n-type Si(100) wafers were implanted at room temperature with 160 keV He ions at a fluence of 5 × 10¹⁶/cm² and 110 keV H ions at a fluence of 1 × 10¹⁶/cm², singly or in combination. Surface phenomena and defect microstructures have been studied by various techniques, including scanning electron microscopy (SEM), atomic force microscopy (AFM) and cross-sectional transmission electron microscopy (XTEM). Surface exfoliation and flaking phenomena were only observed on silicon by successive implantation of He and H ions after subsequent annealing at temperatures above 400 °C. The surface phenomena show strong dependence on the thermal budget. At annealing temperatures ranging from 500 to 700 °C, craters with size of about 10 μm were produced throughout the silicon surface. As increasing temperature to 800 °C, most of the implanted layer was sheared, leaving structures like islands on the surface. AFM observations have demonstrated that the implanted layer is mainly transfered at the depth around 960 nm, which is quite consistent with the range of the ions. XTEM observations have revealed that the additional low fluence H ion implantation could significantly influence thermal growth of He-cavities, which gives rise to a monolayer of cavities surrounded by a large amount of dislocations and strain. The surface exfoliation effects have been tentatively interpreted in combination of AFM and XTEM results.     

Modification of DLC films by Ni ions implantation

Enhanced diamond-like carbon (DLC) multilayer films were produced by a method of alternating the magnetic filtered vacuum cathode arc deposition and the metal vapor vacuum arc (MEVVA) implantation of Ni⁺ ions. The microstructure and mechanical properties of these multilayer films were studied by XPS, Raman, SEM, AFM, XRD, nano-intender and internal stress measurement. The results reveal that with the increasing dose of implanted Ni⁺ ions, the sp³ contents are declining and reduction of the nanohardness and release of the internal stress are observed.     

Microstructure of ion-implanted region in TiNi alloy

TiNi alloy samples implanted with various fluences of 3 MeV Cu²⁺ ions were characterized by transmission electron microscope (TEM) and X-ray diffractometer. Cross-sectional TEM images of the samples showed that amorphous region was seen at the fluence of 10¹⁴ ions cm^?2 in case of ion implantation at 300 K of the substrate temperature, but in case of ion implantation at 100 K it did not appear even at 10¹⁵ ions cm^?2. These results were also confirmed by X-ray diffraction profiles of the same samples. Consequently, the extent of microstructure change of TiNi alloy by ion implantation was different depending on the substrate temperature.     

Localised modifications of anatase TiO2 thin films by a Focused Ion Beam

A Focused Ion Beam (FIB) has been used to implant micrometer-sized areas of polycrystalline anatase TiO₂ thin films with Ga⁺ ions using fluencies from 10¹⁵ to 10¹⁷ ions/cm². The evolution of the surface morphology was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, the chemical modifications of the surface were followed by X-ray photoelectron spectroscopy (XPS). The implanted areas show a noticeable change in surface morphology as compared to the as-deposited surface. The surface loses its grainy morphology to gradually become a smooth surface with a RMS roughness of less than 1 nm for the highest ion fluence used. The surface recession or depth of the irradiated area increases with ion fluence, but the rate with which the depth increases changes at around 5 × 10¹⁶ ions/cm². Comparison with implantation of a pre-irradiated surface indicates that the initial surface morphology may have a large effect on the surface recession rate. Detailed analysis of the XPS spectra shows that the oxidation state of Ti and O apparently does not change, whereas the implanted gallium exists in an oxidation state related to Ga₂O₃.     

Recharging processes, radiation induced strain and changes of OH bands under H ion implantation in Ti doped lithium niobate

A systematic analysis of variations in structural and optical characteristics of Z-cut plates of titanium doped congruent lithium niobate single crystals implanted with 120 keV proton beam at various fluences of 10¹⁵, 10¹⁶ and 10¹⁷ protons/cm² is presented. Through, high resolution X-ray diffraction, atomic force microscopy, Fourier transform infrared and UV-visible-NIR analysis of congruent lithium niobate, the correlation of properties before and after implantation are discussed. HRXRD (0 0 6) reflection by Triple Crystal Mode shows that both tensile and compressive strain peak are produced by the high fluence implantation. A distinct tensile peak was observed from implanted region for a fluence of 10¹⁶ protons/cm². AFM micrographs indicate mountain ridges, bumps and protrusions on target surface on implantation. UV-visible-NIR spectra reveal an increase in charge transfer between Ti³⁺/Ti⁴⁺ and ligand oxygen for implantation with 10¹⁵ protons/cm², while spectra for higher fluence implanted samples show complex absorption band in the region from 380-1100 nm. Variations of OH⁻ stretching vibration mode were observed for cLN Pure, cLNT2% virgin, and implanted samples with FTIR spectra. The concentration of OH⁻ ion before and after implantation was calculated from integral absorption intensity. The effect of 120 keV proton implantation induced structural, surface and optical studies were correlated.     

Effects of neutron-induced ion implantation into blanket structural materials

The high flux of energetic neutrons in CTR blankets will lead to an appreciable implantation of light particles in structural materials as a consequence of neutron impacts. The influence of implanted helium and lithium on the material properties of CTR structural materials should be known because both media are prospective coolants. 30keV lithium ions were implanted into pre-thinned Nb foils. Electron micrographs showed black dots which were identified as precipitates of Li. A concentration profile of He in Nb, which suitably simulates the implantation profile in CTR's, was obtained with the help of the ¹⁰B(n, α)⁷Li reaction. Nb samples which were irradiated up to a He dose of 6 × 10¹⁶ cm^?2 showed heavily damaged surfaces after annealing. Surface erosion of CTR blanket materials due to this process cannot be excluded.     

Effect of CH<Subscript>4</Subscript> Ion Implantation in Pure Aluminium

In this paper, aluminium samples with 99.96% purity were exposed to ion beam, extracted from CH₄ plasma. Implantation of ions were performed for 50 keV energy and various doses ranging from 1 × 10¹⁷ to 6 × 10¹⁷ ions/cm². Morphology of surfaces, roughness and its evolution during variation of ion dose has been studied by atomic force microscopy (AFM). Microstructure of the modified surfaces after ion implantation has been obtained by X-ray diffraction technique and Raman spectroscopy. Formation of aluminium carbide (Al₄C₃) was confirmed by XRD results at implantation doses of 3 × 10¹⁷ and 6 × 10¹⁷ ions/cm². In addition, it was observed that when the ion dose is increased, orientation of aluminium planes change from (2 2 0) to (2 0 0). Corrosion test was performed and compared for implanted and un-implanted samples. The results showed that corrosion resistivity increase by accumulation of ion dose.     

Effect of Nitrogen Ion Implantation in Copper

In this study, copper samples with 99% purity implanted by N⁺ and N₂ ⁺ ions. Implantation of ions performed at 50 keV and various doses ranging from 1 × 10¹⁷ to 1 × 10¹⁸ ions/cm². Morphology of samples’ surface studied by atomic force microscopy. Microstructure of modified surfaces after ion implantation obtained using grazing incidence X-ray diffraction technique (GIXRD). Formation of both copper nitride and copper trinities confirmed by GIXRD results. Microhardness properties and corrosion behavior of implanted samples measured by Vickers and corrosion test, respectively. The maximum hardness of copper surface observed after nitrogen ion implantation at the dose of 3 × 10¹⁷ ions/cm². Moreover, the results showed that corrosion resistivity significantly increase.     

Effects of MPII-implanted titanium on the electrochromic properties of tungsten trioxide

There are great interests in electrochromic (EC) technology for smart windows and displays over the last decade. The substrate, a conductive glass being coated indium tin oxide (ITO) thin films, deposited tungsten trioxide (WO₃) using radio-frequency (RF) sputtering and implanted Ti by a metal-plasma ion implantation (MPII) in this study. The optical density (when the implanted dose is less than 2 × 10¹⁵ ions/cm²) is approximately 1.6 times the unimplanted Ti. At low implanted dose +6 valence tungsten ions improve optical density. At high implanted dose, low-valence tungsten ions reduce the optical density.     

Comparison of High-Energy He+ and D+ Irradiation Impact on Tungsten Surface in the IR-IECF Device

Polycrystalline tungsten specimens were irradiated in the Iranian Inertial Electrostatic Confinement Fusion device (IR-IECF) by high energy (~100 keV) and high fluency (~10¹⁹ ions/cm²) helium and deuterium plasma to investigate the implantation impact of high energetic ions on tungsten as a candidate for fusion first wall material. Comparison of the exposure by He and D₂ plasma and influence of high temperature (~1,100 °C) implantation of each ion has been examined. Scanning electron microscopy was used to investigate surface morphology changes for various ion fluencies. Results showed the onset of visible surface pores formation especially for helium implanted samples which increased with higher implant fluencies, eventually resulting in a rough and flaky surface structure, unlike deuterium implanted samples on which smoothening of the surface occurred. Microhardness measurements were used to evaluate mechanical properties of implanted tungsten. Each specimen sustained surface hardening after implantation which was observed to increase with greater ion dose. The phase formation and structural evolution were studied by X-ray diffractometry method.     

Studies on the high electronic energy deposition in polyaniline thin films

We report here the physico-chemical changes brought about by high electronic energy deposition of gold ions in HCl doped polyaniline (PANI) thin films. PANI thin films were synthesized by in situ polymerization technique. The as-synthesized PANI thin films of thickness 160 nm were irradiated using Au⁷⁺ ion of 100 MeV energy at different fluences, namely, 5 × 10¹¹ ions/cm² and 5 × 10¹² ions/cm², respectively. A significant change was seen after irradiation in electrical and photo conductivity, which may be related to increased carrier concentration, and structural modifications in the polymer film. In addition, the high electronic energy deposition showed other effects like cross-linking of polymer chains, bond breaking and creation of defect sites. AFM observations revealed mountainous type features in all (before and after irradiation) PANI samples. The average size (diameter) and density of such mountainous clusters were found to be related with the ion fluence. The AFM profiles also showed change in the surface roughness of the films with respect to irradiation, which is one of the peculiarity of the high electronic energy deposition technique.     

Characterization of high energy ion implantation into Ti-6Al-4V

Ion implantation is a surface modification process that can improve the wear, fatigue, and corrosion resistance for several metals and alloys. Much of the research to date has focused on ion energies less than 1 MeV. With this in mind, Ti-6Al-4V was implanted with Al²⁺, Au³⁺, and N⁺ ions at energies of 1.5 and 5 MeV and various doses to determine the effects on strengthening of a high energy beam. A post heat treatment on the specimens implanted with Al²⁺ samples was conducted to precipitate Ti_xAl type intermetallics near the surface. Novel techniques, such as nanoindentation, are available now to determine structure-mechanical property relationships in near-surface regions of the implanted samples. Thus, nanoindentation was performed on pre-implanted, as-implanted, and post heat treated samples to detect differences in elastic modulus and hardness at the sub-micron scale. In addition, sliding wear tests were performed to qualitatively determine the changes in wear performance. The effect of this processing was significant for samples implanted with Al²⁺ ions at 1.5 MeV with a dose higher than 1 × 10¹⁶ ions/cm² where precipitation hardening likely occurs and with N⁺ ions.