Carbonization in boron-ion-implanted polymethylmethacrylate as revealed from Raman spectroscopy and electrical measurements

ABSTRACT

The results of Raman spectroscopy and electrical measurements of 40 keV boron-ion-implanted polymethylmethacrylate with ion doses from 6.25 × 10¹⁴ to 5.0 × 10¹⁶ ions/cm² are reported for the first time. The Raman spectra recorded in the 400–3800 cm^?1 range, showing the formation of new carbon–carbon bands for the as-implanted samples at higher ion doses (>10¹⁶ ions/cm²), are found to be an additional support for carbonization processes earlier revealed by slow positrons. The current–voltage dependences at 360 K testify also that the as-implanted samples examined with higher fluences (3.75 × 10¹⁶ and 5.0 × 10¹⁶ ions/cm²) have created a very thin conductive layer or conductive joints due to carbonization.     

Modification of the magnetic properties of polyimide films by cobalt ion implantation

The magnetic characteristics of polyimide films implanted with Co⁺ ions with an energy of 40 keV in the dose range D = 2.50 × 10¹⁶?1.25 × 10¹⁷ cm^?2 at ion current densities j = 4, 8, and 12 μA/cm² have been investigated. It has been shown that, at implantation doses of less than 5 × 10¹⁶ cm^?2, the superparamagnetic properties of modified samples are described by the Langevin equation. At higher doses, there is an intercluster interaction. It has been found that, with an increase in the ion current, the cluster size decreases. The sizes of the formed clusters are determined and vary in the range from 3.9 to 11.0 nm, depending on the implantation dose.     

Investigation of irradiated and annealed high-temperature superconducting films with the Umka nanotechnological complex

Superconducting YBa₂Cu₃O_{7 ? x} films were fabricated by dc magnetron sputtering. They were irradiated with 1.2-MeV He⁺ ions to doses of 4 × 10¹⁵, 8 × 10¹⁵, 16 × 10¹⁵, and 32 × 10¹⁵ cm^?2. The irradiated films were subjected to stepwise (30 min per step) vacuum annealing at 500, 600, 700, 800, and 900°C. After vacuum annealing, the samples irradiated to doses of 4 × 10¹⁵, 8 × 10¹⁵, and 16 × 10¹⁵ cm^?2 exhibited partial recovery of their critical temperature, whereas the sample with a dose of 32 × 10¹⁵ cm^?2 exhibited no signs of partial recovery of T _C. Investigation of the irradiated annealed samples with the Umka nanotechnological complex has revealed damaged surface regions extended to a relatively large (several tenths of a micrometer) depth.     

Changes in Structural and Optical Properties of Polycarbonate Induced by Ag+ Ion Implantation

Transparent polycarbonate samples were implanted with 1 MeV Ag⁺ ions to various doses ranging from 5 × 10¹⁴ to 3 × 10¹⁶ ions cm^?2 with a beam current density of 900 nA cm^?2. Modification in the structure of polycarbonate as a function of the implantation fluence was investigated using micro-Raman spectroscopy, glancing angle X-ray diffraction, and UV-Vis spectroscopy. Raman spectroscopy pointed toward the formation of graphite structures/clusters due to the ion implantation. UV-Vis absorption analysis suggests the formation of a carbonaceous layer and a drastic decrease in optical band gap from 4.12 eV to 0.50 eV at an implanted dose of 3 × 10¹⁶ ions cm^?2. The correlation between the decrease in band gap and the structural changes is discussed.     

CEMS study on aluminium implanted iron

Up to now a great deal of investigations in ion beam mixing of iron-aluminium layers are known. However, the easier way to produce such layers by direct implantation of aluminium ions in iron is less studied. In the present work aluminium implanted iron layers are studied. Iron samples were implanted with aluminium ions at 50, 100, and 200 keV, respectively, with doses between 5×10¹⁶ and 5×10¹⁷ cm⁻². Independent of energy, at doses up to 2×10¹⁷ cm⁻², besides alpha iron further magnetic fractions with a Fe₃Al-like structure are formed while at a dose of 5×10¹⁷ cm⁻² amorphous nonmagnetic components are formed.     

Crystalline to amorphous transformations in ion implanted GaP

Abstract

The amorphization process of GaP by ion implantation is studied. The samples of 〈111〉 oriented GaP were implanted at 130 K with various doses 5 × 10¹³-2 × 10¹⁶ cm^?2 of 150 keV N⁺ ions and with the doses of 6 × 10¹²-1.5 × 10¹⁵ cm^?2 of 150 keV Cd⁺ ions. Room temperature implantations were also performed to see the influence of temperature on defect production. Rutherford backscattering and channelling techniques were used to determine damage in crystals. The damage distributions calculated from the RBS spectra have been compared with the results of Monte-Carlo simulation of the defect creation.

The estimated threshold damage density appeared to be independent on ion mass and is equal 6.5 × 10²⁰ keV/cm³. It is suggested that amorphization of GaP is well explained on the basis of a homogenous model.     

On the relative stability of different topographical features developed on bombarded copper surfaces

The morphological evolution of different topographical features (namely cones, ridges, cliffs, and featureless planes), as developed on bombarded copper surfaces as a function of consecutive doses of mass-separated 12 keV Kr⁺ ions, has been compared. The doses ranged from 1.2 × 10¹⁷ ions/cm² up to 3 × 10¹⁹ ions/cm². We found clear experimental evidence, valid at least for copper as here prepared, that the order of increasing relative stability is cone-ridge-cliff-plane.     

Magnetic resonance of metallic nanoparticles in vitreous silicon dioxide implanted with iron ions

Silica glasses exposed to steady-state and pulsed irradiation with Fe⁺ ions are studied using magnetic resonance. The irradiation doses used in experiments are equal to 1 × 10¹⁵, 1 × 10¹⁶, and 1 × 10¹⁷ cm^?2. It is found that, under both steady-state and pulsed irradiation conditions, glass samples exposed at a dose of 1 × 10¹⁷ cm^?2 exhibit a broadband orientation-dependent signal. The shape of inclusions is evaluated under the assumption that the observed spectrum is caused by the ferromagnetic resonance induced in a new phase of metallic iron.     

Synthesis of Ag metallic nanoparticles by 120 keV Ag− ion implantation in TiO2 matrix

TiO₂ thin film synthesized by the RF sputtering method has been implanted by 120 keV Ag^? ion with different doses (3?×?10¹⁴, 1?×?10¹⁵, 3?×?10¹⁵, 1?×?10¹⁶ and 3?×?10¹⁶ ions/cm²). Further, these were characterized by Rutherford back Scattering, XRD, X-ray photoelectron spectroscopy (XPS), UV–visible and fluorescence spectroscopy. Here we reported that after implantation, localized surface Plasmon resonance has been observed for the fluence 3?×?10¹⁶ ions/cm², which was due to the formation of silver nanoparticles. Ag is in metallic form in the matrix of TiO₂, which is very interestingly as oxidation of Ag was reported after implantation. Also, we have observed the interaction between nanoparticles of Ag and TiO₂, which results in an increasing intensity in lower charge states (Ti³⁺) of Ti. This interaction is supported by XPS and fluorescence spectroscopy, which can help improve photo catalysis and antibacterial properties.     

Annealing of arsenic-and antimony-implanted silicon single crystals using A CW xenon arc lamp

Abstract

Continuous, incoherent light from a xenon arc lamp has been used to anneal radiation damage in <100> silicon single crystals produced by implantation of 30?keV arsenic or antimony ions to doses between 1×10¹⁵ cm^?2 and 1×10¹⁶ cm^?2. The recrystallized layers have been characterized by Rutherford-backscattering spectroscopy, ion-channeling, Transmission Electron Microscopy, and sheet-resistivity measurements.     

锆离子注入锆-4合金缺陷的慢正电子研究

采用慢正电子束多普勒展宽谱研究了Zr离子注入Zr-4合金产生的缺陷及其退火回复行为，发现经过大于离子注入剂量为1×10¹⁶cm^-2的样品所产生的缺陷在注入过程中已经回复，而对剂量为1×10¹⁵cm^-2样品做300℃退火处理，其缺陷基本回复，得出合金缺陷回复能较低的结论. 考虑到材料的缺陷含量越高，其抗腐蚀性能越差，在辐照环境下通过给材料保持一定温度，即可使其缺陷得到较好回复，从而提高材料的抗腐蚀性能.     

Effect of N5+ ion irradiation on l-ornithine monohydrochloride single crystals: an organic nonlinear optical material

In this work, the authors have grown good-quality single crystals of l-ornithine monohydrochloride (LOHCL), an organic nonlinear optical material, in the aqueous solution by the slow cooling technique. N⁵⁺ ion irradiation of three different doses (i.e. 1?×?10¹⁶, 5?×?10¹⁶ and 1?×?10¹⁷?ions/cm²) at room temperature was done on the cut and polished crystal specimen of appropriate size from the grown crystal. A detailed study of FT-Raman spectroscopic was carried out to see the effect of irradiation on structure and vibrational modes of the LOHCL crystal. The results revealed that there is no structural modification even at high doses except the variation in peak intensity, which indicates that the grown crystals of LOHCL have good stability and also confirms that the nitrogen ions do not substitute into the crystal lattice. The UV–Vis–near-infrared spectroscopic study was done on all the samples to see the effect of irradiation and various optical parameters such as transmittance (～50–70%), absorption coefficient, energy band gap (～4.75–4.96?eV), extinction coefficient, refractive index (～1.31–1.24), optical permittivity (～1.7–1.6) and susceptibility (～0.7–0.6). The calculated optical parameters were found to vary with change in doses.     

Influence of irradiation damage on formation of iron nitrides in α-Fe

Pure iron foils were implanted with nitrogen ions at energy of 10 keV and with 1×10¹⁷N ions/cm². Doses of pre-self-implantation were 5×10¹⁶ and 3.7×10^{16 17}Fe ions/cm² respectively, and the iron ion energy was 27 keV. A comparison of iron nitrides formed on surfaces with and without pre-self-implantation has been obtained. The results show that radiation damage apparently influences the formation of iron nitrides. The formation and transformation of nitrides after N implantation or after annealing can be explained by a model of implantation-induced transformation.     

Ion synthesis of silver nanoparticles in viscous-fluid epoxy resin

A method is described for the ion synthesis of silver nanoparticles in epoxy resin that is in a viscousfluid state (viscosity 30 Pa s) during irradiation. The viscous-fluid or glassy polymer is implanted by 30-keV silver ions at a current density of 4 μA/cm² in the ion beam in the dose range 2.2 × 10¹⁶–7.5 × 10¹⁶ ions/cm². The epoxy layers thus synthesized contain silver nanoparticles, which are studied by transmission electron microscopy and optical absorption spectroscopy. The use of the viscous-fluid state increases the diffusion coefficient of the implanted impurity, which stimulates the nucleation and growth of nanoparticles at low implantation doses and allows a high factor of filling of the polymer with the metal to be achieved.     

Effect of nitrogen ions on the structural,optical, and thermal properties of polyvinyl alcohol/starch blend

This work examines the properties of polyvinyl alcohol (PVA)/starch film containing glycerol as a plasticizer under exposure to different nitrogen ion fluence. The prepared PVA/starch blend was irradiated with ion fluence from 3 × 10¹⁷ to 12 × 10¹⁷ ions.cm⁻². From FTIR, the ion beam irradiation attack and weakens the C–H bond in PVA/starch blend. From XRD findings, the crystallite size of the blend decreased at 3 × 10¹⁷ ions/cm² while it increased at higher fluence up to 9 × 10¹⁷ ions/cm². This indicates the degradation of the blend at low ion fluence compared to crosslinking at high ion fluence. Also, the optical bandgap of the blend was decreased with an increase in ion fluence. Furthermore, the effect of N⁺ ions on some optical dispersion parameters is studied. The thermal stability of the PVA/starch blend shows a decrease in thermal stability upon irradiation with 3 × 10¹⁷ ions/cm² compared to higher thermal stability at higher doses up to 9 × 10¹⁷ ions/cm².     

A cems study of119Sn ion-implanted into Ni

Conversion electron Mössbauer spectroscopy (CEMS) was applied to study the behaviour of¹¹⁹Sn atoms implanted into Ni at the accelerating energy of 100–400KeV and doses of 5×10¹⁵–5×10¹⁶ ions/cm² at room temperature. All CEMS spectra were measured at room temperature and successfully analyzed by two components. The energy and dose dependence of CEMS spectra were well explained by the depth distribution of¹¹⁹Sn atoms.     

Structural and compositional changes in ion-bombarded Ta2O5

A detailed study of the effect of heavy-ion bombardment on Ta₂O₅ has been undertaken using a combination of radioactive tracer techniques, electron microscopy, and Rutherford backscattering. Crystalline Ta₂O₅ is amorphized at ~6 × 10¹³ ions cm^?2, while at a dose of ~5 × 10¹⁶ ions cm^?2 the electron microscopy reveals the development of random grains of a new crystalline phase. By ~1 × 10¹⁷ ions cm^?2 the grains are not yet overlapping but still yield a diffraction pattern consistent with either δ-Ta-O (not to be confused with TaO) or Ta_1?xO₂, thus indicating that Ta₂O₅, like most other transition-metal oxides, is subject to preferential sputtering. Preferential sputtering was confirmed by backscattering analysis of specimens bombarded to high doses, where the average surface composition was found to be Ta_1.8±0.2O₂ or, equivalently, Ta₂O_2.2±0.2. The surface alteration had an average composition independent of the mass and energy of the incident ions.     

The near surface changes in boron implanted 4145 steel

Boron implanted 4145 steel was evaluated for changes in the near-surface region property such as microhardness. The surfaces when implanted with ¹¹B⁺ ions at 135 keV energy to a dose 1 × 10¹⁷ ions cm^?2 resulted in increase of microhardness for 10 to 40 gms of applied load. An increase upto 40% in microhardness could be observed in the specimen when annealed at 310δC for 3 hours. Furthermore, the effect of ion-beam induced intermixing of 250Å thin carbon film due to boron implantation was also studied for different doses ranging from 1 × 10¹⁷ to 3 × 10¹⁷ boron ions cm^?2. An increase in microhardness with applied load was observed for 1 × 10¹⁷ ions cm^?2 concentration, while hardest layer was formed at 3 × 10¹⁷ ions cm^?2 dose which practically had very little effect to 10 and 20 gms of load.     

Ferromagnetism of Mn-implanted silicon: Magnetization and magnetooptic faraday effect

Manganese-implanted silicon plates of both n and p types have been obtained by implanting 195-keV manganese ions with doses from 1 × 10¹⁵ to 2 × 10¹⁶ cm^?2. According to magnetic measurements by a vibrating sample magnetometer and a SQUID magnetometer, all of the samples exhibit a ferromagnetic ordering at room temperature. The magnetooptic Faraday effect is manifested in the spectral region 1–6 μm in the temperature interval 80–305 K. The characteristic features of the field and temperature dependences of magnetization and the spectrum of the Faraday effect indicate a percolation type of magnetic ordering at low temperatures and a crucial role of the exchange between delocalized p-type carriers and Mn ions at temperatures above 100 K.