Elastic Recoil Detection Analysis Technique Research Articles

Energy loss straggling data of 63Cu, 28Si, 27Al, 24Mg, 19F and16O heavy ions crossing thin polymeric foils at low energy

Throughout this work we present and analyse the inter-comparison result that we carried out between the energy loss straggling of 63Cu, 28Si, 27Al, 24Mg, 19F and16O partially stripped heavy ions crossing thin polymeric foils such as: Mylar, Polypropylene, Plexiglas and PVC, over a continuous range of energies 0.045–0.62 MeV/n, obtained experimentally and those calculated by the different theoretical formulations defining the energy loss straggling namely; straggling of Bohr, Bethe-Livingston, Lindhard-Scharff and the empirical formula developed by Yang et al. The experimental straggling data obtained in the framework with a precision of ±20% and nonexistent in the literature so far, have been generated by using Heavy Ion Elastic Recoil Detection Analysis (HIERDA) technique coupled with Time of Flight (ToF) spectrometer. In view of significant deviations obtained between experimental straggling data and those calculated theoretically, we can say that Bohr’s classical theory and other theories derived from Bohr’s classical theory (Lindhard-Scharff, Bethe-Livingston or Yang) are insufficient to describe correctly our obtained experimental straggling data over the investigated energy range.

Li depth profiles of metal/Li-electrolyte/metal capacitors under biasing studied by means of MeV ion beam analysis techniques

Li Depth profiles at the interfaces of capacitors of Cu/LiPON/Cu and Al/LiPON/Al prepared on buffer Ti layer /SiO2glass and Au/LATP/Au (LiPON = Li3.3PO3.8N0.2, LATP = Li3.1Al0.84Ti1.16Ge1.27P1.73O12) under biasing bottom metal against top metal at earth potential have been in-situ measured by means of elastic recoil detection analysis (ERD) and Rutherford backscattering spectrometry (RBS) techniques. Li has been found to be enriched near the interface with electrode biased negatively, while it is depleted near that biased positively. The Li depth profile in electrolyte has been theoretically calculated, taking into account the transport faction of Li ions, based on hopping diffusion model of Li ions under potential gradient. It is shown that the Li depth profile calculated as a solution of diffusion equation at steady state agrees qualitatively well with the experimental ones and the transport fraction of Li ions in electrolyte is less than unity.

Hydrogen depth profiles and microhardness of electrochemically hydrogen-charged nanostructured bainitic steels

Abstract Hydrogen depth profiles and microhardness of the electrochemically hydrogen-charged nanostructured bainitic steels (produced at two different transformation temperatures, i.e. 200 °C (NBS200) and 350 °C (NBS350)) were obtained using elastic recoil detection analysis (ERDA) technique and Vickers microhardness testing, respectively, and compared to that of mild steel. The ERDA results showed that the subsurface hydrogen concentration was higher in NBS200, followed by NBS350 and mild steel. However, the microhardness data of the hydrogen-charged steels revealed material softening in NBS200 and NBS350, whereas the mild steel exhibited material hardening effect. The microhardness along the cross-sectional depth of the steels showed that the softening effect in NBS200 was closer to the hydrogen-charged surface compared to that of NBS350. The plausible mechanisms for the softening effect in the NBS200 and NBS350, and hardening effect in mild steel have been discussed in this paper.

Ion beam synthesis of SiC on Si toward the radiation damage free limit

Transmission Electron Microscopy (TEM), Rutherford Backscattering Spectrometry in random and aligned to Si 001-channel direction, and Elastic Recoil Detection Analysis (ERDA) techniques were employed to characterize SiC structures obtained by Ion Beam Synthesis. C+ ions at 40 keV were implanted up to a fluence of 2.8 × 1017 cm−2 into a (001) Si substrate capped by a SiO2 layer. Samples with SiO2-cap thicknesses of 110, 190 and 240 nm were compared. For the first two of them, 72% and 11% of C+ ions, respectively, are directly implanted into the Si substrate, however, for the later, no carbon directly reaches the substrate. C+ implantation was performed with samples held at 600 °C and, afterwards, they were annealed at 1250 °C for 2 h under a flux consisting of a mixture of 99% Ar and 1% O2. ERDA demonstrates that C redistribution occurs in the 240 nm SiO2-cap and TEM, Selected Area Diffraction and Channeling revealed an almost continuous cubic and epitaxial SiC layer of about 5–7 nm on the Si surface. This SiC nanolayer presented the optimum crystalline quality, from the standpoint of HRTEM imaging and Channeling results. This synthesis was exclusively based on C migration to the SiO2/Si interface, followed by SiC nucleation during interfacial reconstruction of the crystal structure. The improved quality is justified because the interface is not affected by any implantation damage. On the other end, the synthesis by using the 110 nm SiO2-cap is obtained by direct C inclusion into the Si structure, but also results in epitaxial SiC. The 190 nm SiO2-cap showed, however, a strong regression in the quality: it revealed misaligned grains of SiC immerse in an amorphous narrow layer. Two distinct mechanisms are responsible for SiC synthesis, depending on the cap-layer thickness, and the influence of the radiation damage for each is discussed.

Energy loss and stopping force of heavy ions Cu, Si, Al and F through thin Nickel (Ni) foil at low MeV energies

The slowing down of Cu, Si, Al and F heavy ions over the 0.09–0.51 MeV/nucleon energy range in thin Nickel (Ni) foil has been investigated by using the Heavy Ion Elastic Recoil Detection Analysis (HI-ERDA) technique coupled with a time of flight (ToF) spectrometer. This experimental setup generated a significant amount of energy loss data, which allowed the determination of stopping force of 63Cu7+ heavy ions in Nickel at low projectile energies. The obtained stopping force results were compared with semi-empirical calculations by Ziegler’s Stopping and Range of Ions in Matter (SRIM) code, and ab initio calculations by Grande and Schiewietz’s Convolution approximation for swift Particles (CasP) code. The aim of such comparison was to assess the reliability and accuracy of the existing energy loss formulations, in the light of the present experimental results. Good agreement was found between the experimental stopping force data for the reported ions velocities and SRIM predictions. For CasP, the agreement is fairly good from ∼0.15 MeV/n onwards.

The Structural and Compositional Changes of Graphene Oxide Induced by Irradiation With 500 keV Helium and Gallium Ions

Structural and compositional modification of 2D materials as graphene or graphene oxide (GO) are topical objects of nowadays due to their many technological applications. Ion irradiation of graphene based materials, as a method for improvement of their surface properties started recently. Ion mass, energy, and fluence are crucial for forming of GO electrical, optical, and mechanical properties. In this work, the GO films are irradiated with 500 keV He and Ga ions to different fluences. The ions with different masses and electronic/nuclear stopping power ratios, are chosen with the aim to examine mechanisms of radiation defect creation. The elemental composition of the GO is investigated using Rutherford back‐scattering (RBS) and elastic recoil detection analysis (ERDA) techniques. The structural and chemical changes are characterized by X‐ray photoelectron spectroscopy (XPS) and Raman spectroscopy and the electrical properties are determined by two‐point method. The RBS and ERDA analyses indicate deoxygenation and dehydrogenation of the irradiated GO surface. The thickness and the degree of O and H depletion depend on the ion mass. XPS and Raman spectroscopy show removal of oxygen functionalities and structural modifications leading to a decrease in the surface resistivity.

Investigation of graphene oxide-hydrogen interaction using in-situ X-ray diffraction studies

Hydrogen is one of the alternatives as clean fuel for our growing demands for energy. However, its storage for practical applications is a challenge due to low energy density. The interaction mechanism between the hydrogen gas and the host involved plays a vital role to explore its potential application as hydrogen storage material. So, in the present work, we have studied the interaction of Graphene oxide with hydrogen gas at different pressures varying from 70 mbar to 900 mbar at room temperature using reliable in-situ X-ray diffraction technique. XRD patterns showed that the hydrogen gas induced strain up to ∼6.3% in GO films for 1% and 10% hydrogen atmosphere. The interaction mechanism was studied qualitatively using Raman spectroscopy and Fourier transform infra-red (FTIR) spectroscopy. Elastic recoil detection analysis (ERDA) technique was employed to determine the concentration of hydrogen in GO film which increased from ∼1.7 × 1022 atoms/cc (for pristine GO) to ∼ 9.5 × 1022 atoms/cc after exposing to 100% hydrogen environment at 900 mbar pressure.

Atomic Layer Deposition of Rhenium Disulfide.

2D materials research is advancing rapidly as various new "beyond graphene" materials are fabricated, their properties studied, and materials tested in various applications. Rhenium disulfide is one of the 2D transition metal dichalcogenides that has recently shown to possess extraordinary properties such as that it is not limited by the strict monolayer thickness requirements. The unique inherent decoupling of monolayers in ReS2 combined with a direct bandgap and highly anisotropic properties makes ReS2 one of the most interesting 2D materials for a plethora of applications. Here, a highly controllable and precise atomic layer deposition (ALD) technique is applied to deposit ReS2 thin films. Film growth is demonstrated on large area (5 cm × 5 cm) substrates at moderate deposition temperatures between 120 and 500 °C, and the films are extensively characterized using field emission scanning electron microscopy/energy-dispersive X-ray spectroscopy, X-ray diffractometry using grazing incidence, atomic force microscopy, focused ion beam/transmission electron microscopy, X-ray photoelectron spectroscopy, and time-of-flight elastic recoil detection analysis techniques. The developed ReS2 ALD process highlights the potential of the material for applications beyond planar structure architectures. The ALD process also offers a route to an upgrade to an industrial scale.

ERDA at the 9 MV Tandem and at the 3 MV Tandetron of IFIN-HH

Recoil spectrometry using heavy ions proposed in 1976 by L’Ecuyer has evolved into a universal IBA technique. Few years later an experimental setup for simultaneous light and medium heavy element detection including a compact ΔE(gas)–Er(solid) telescope, was developed at the Tandem accelerator of IFIN-HH. To increase the resolution, an integrated preamplifier was mounted close to the ionization chamber. The calibration procedure for the telescope and the software for the quantitative evaluation of the data are briefly presented. Recently, a 3MV Tandetron accelerator has been installed and commissioned at the IFIN-HH. Among several ion-beam techniques for detection and depth profiling of hydrogen isotopes, Elastic Recoil Detection Analysis (ERDA) technique using a low energy 4He beam, proposed by Doyle and Peercy, is particularly advantageous. By measuring simultaneously both the H or D recoiling at a forward angle and backscattered 4He ions, a rather complete characterization of the sample can be achieved. Selected results from our investigations, obtained using these facilities, are presented.

Development of a versatile user-friendly IBA experimental chamber

Reliable performance of the Ion Beam Analysis (IBA) techniques is based on the accurate geometry of the experimental setup, employment of the reliable nuclear data and implementation of dedicated analysis software for each of the IBA techniques. It has already been shown that geometrical imperfections lead to significant uncertainties in quantifications of IBA measurements. To minimize these uncertainties, a user-friendly experimental chamber with a heuristic sample positioning system for IBA analysis was recently developed in the Van de Graaff laboratory in Tehran. This system enhances IBA capabilities and in particular Nuclear Reaction Analysis (NRA) and Elastic Recoil Detection Analysis (ERDA) techniques. The newly developed sample manipulator provides the possibility of both controlling the tilt angle of the sample and analyzing samples with different thicknesses. Moreover, a reasonable number of samples can be loaded in the sample wheel. A comparison of the measured cross section data of the 16O(d,p1)17O reaction with the data reported in the literature confirms the performance and capability of the newly developed experimental chamber.

Low-temperature atomic layer deposition of copper(II) oxide thin films

Copper(II) oxide thin films were grown by atomic layer deposition (ALD) using bis-(dimethylamino-2-propoxide)copper [Cu(dmap)2] and ozone in a temperature window of 80–140 °C. A thorough characterization of the films was performed using x-ray diffraction, x-ray reflectivity, UV-Vis spectrophotometry, atomic force microscopy, field emission scanning electron microscopy, x-ray photoelectron spectroscopy, and time-of-flight elastic recoil detection analysis techniques. The process was found to produce polycrystalline copper(II) oxide films with a growth rate of 0.2–0.3 Å per cycle. Impurity content in the films was relatively small for a low temperature ALD process.

Energy loss measurements of 63Cu, 28Si and 27Al heavy ions crossing thin Polyvinylchloride (PVC) foil

Experimental stopping data of, 63Cu, 28Si and 27Al heavy ions in thin Polyvinylchloride (H3C2Cl1) foil have been obtained over the 0.045–0.50MeV/nucleon energy range. The measured energy losses were carried out by Heavy Ion Elastic Recoil Detection Analysis (HI-ERDA) technique coupled with time of flight (ToF) spectrometer. A continuous stopping power data obtained in this work are well fitted by our proposed semi-empirical formula and the results are compared to those calculated by LSS formula or generated by SRIM-2013 and MSTAR predictions. Calculations using our formula agree well with the obtained experimental stopping powers, while the LSS formula underestimates the experimental data in the whole investigated energy range. In this work a simple expression for electronic stopping power of heavy ions at low energy in solid targets is introduced. This formula is based on the Firsov and Lindhard–Sharff stopping power models with a small modification made to the original expression, by incorporating the effective charge of moving ions concept and with exponential fit function.

Characterisation of natural and enriched oxygen targets in lithium carbonate foils

A method for making oxygen targets in a form of lithium carbonate compound is described. Targets were prepared for nuclear physics experiments which required oxygen with a mass greater than 60 %. Both natural and isotopic enriched targets of 18O with thicknesses of less than 1 mg/cm2 were produced and characterised by elastic recoil detection analysis and elastic backscattering techniques. The results obtained showed that enriched foils had limited isotopic exchange when exposed to air and good stability with time compared to foils with natural oxygen.

Energy loss straggling data of 28Si, 27Al, 24Mg, 19F, 16O, and 12C heavy ions in thin polymeric Formvar foil over a range of energies 0.1–0.6MeV/u by time-of-flight spectrometry

The energy-loss straggling of 28 Si, 27 Al, 24 Mg, 19 F, 16 O and 12 C partially stripped heavy ions has been determined in Formvar polymeric thin foil over a continuous range of energies 0.1–0.6 MeV/u, by using a powerful method based on the combination of Heavy Ion-Elastic Recoil Detection Analysis (HI-ERDA) technique and Time of Flight (ToF) spectrometer. The obtained energy loss straggling values have been analyzed and compared with the corresponding computed values adopting some widely used energy loss straggling formulations such as, Bohr, Bethe–Livingston and Yang formulas. The aim of such a comparison is to check the reliability and accuracy of the existing energy loss straggling formulations. The experimental results of energy loss straggling of all ions are found to be significantly greater than those predicted by the theories. These differences can be attributed to the charge exchange straggling. This effect has to be taken into account in order to explain the obtained results. • Measurement of energy loss straggling data of 28 Si, 27 Al, 24 Mg, 19 F, 16 O, and 12 C heavy ions in thin polymeric Formvar foil. • The heavy ion elastic recoil detection analysis (HIERDA) technique coupled with time of flight (ToF) spectrometer was used. • The aim of such a study is to check the reliability and accuracy of the existing energy loss straggling formulations.

On the analysis of H in thin layers of Pt electroless contacts using elastic recoil detection technique

Cadmium telluride CdTe is a II–VI binary semiconductor, which has multiple applications, especially in nuclear, X-ray and gamma ray detection. In such applications, the material can be made more resistive by compensation with halogen elements like Cl. However, this compensation has a side-effect on the detectors, the “polarization effect”, which decreases the detector efficiency. One way to reduce this effect is the use of quasi-ohmic contacts deposited by a spontaneous electro-chemical deposition method, so-called “electroless deposition”, of metals such as Pt. Indeed, the use of this electroless deposition method will induce a great amount of hydrogen in the solution and, consequently, part of it will be present in the new formed layers. Since hydrogen content will affect the electrical and optical properties of semiconductors, the aim of this paper is to investigate the concentration profile of H in the contact layers, using Elastic Recoil Detection Analysis technique ERDA, where samples are analyzed as a function of the dilution and pH value of the deposition solution. The preliminary results show that a H atomic concentration as high as 2×1020atoms/cm3 is found in the interfacial layer. Correlations with detection properties and a new polarization healing model are proposed.

Deposition and current conduction of mixed hexagonal and cubic phases of AlN/p-Si films prepared by vacuum arc discharge: Effect of deposition temperature

Cubic and hexagonal AlN films have been prepared by vacuum arc discharge technique at different deposition temperatures 100, 200 and 300°C. The depositions were carried out from pure aluminum targets under nitrogen gas on p-type Si substrates, with Al forming the gate in a metal–insulator–semiconductor configuration. Preferential orientations (111) and (002) of the cubic and hexagonal phases have been affirmed by X-ray diffraction analysis. The Fourier transform infrared spectra revealed the manifestation of the two phases as well. The effect of deposition temperature on the crystalline quality and texture of the films has been also investigated and the grain size of which, has been evaluated as a function of temperature. The best crystalline quality i.e., largest grain size was found to be at 200°C. The composition and stoichiometry of the films have been determined by the time-of-flight elastic recoil detection analysis (TOF-ERDA) and Rutherford backscattering techniques. The Al/N ratio was found to be around 1, while the O content was less than 1.8%. Scanning electron microscopy and TOF-ERDA measurements demonstrated films thickness of 260nm. Current density versus electric field and capacitance–voltage (C–V) measurements were also investigated to reveal the field emission and conduction mechanism of the Al/AlN/p-Si devices. Schottky, Pool–Frenkel and Fowler–Nordheim conduction have been found to contribute to the electron transport, and the best emission properties were manifested at 200°C with a highest current density 525μA/cm2 at a field 71V/μm. From C–V curves, the density of traps has been estimated to be 18×109cm−2eV−1 indicating a good quality of the deposited films.

Hydrogen plasma induced modification of photoluminescence from a-SiNx:H thin films

Low temperature (250–350 °C) hydrogen plasma annealing (HPA) treatments have been performed on amorphous hydrogenated silicon nitride (a-SiNx:H) thin films having a range of compositions and subsequent modification of photoluminescence (PL) is investigated. The PL spectral shape and peak positions for the as deposited films could be tuned with composition and excitation energies. HPA induced modification of PL of these films is found to depend on the N/Si ratio (x). Upon HPA, the PL spectra show an emergence of a red emission band for x ≤ 1, whereas an overall increase of intensity without change in the spectral shape is observed for x > 1. The emission observed in the Si rich films is attributed to nanoscale a-Si:H inclusions. The enhancement is maximum for off-stoichiometric films (x ∼ 1) and decreases as the compositions of a-Si (x = 0) and a-Si3N4 (x = 1.33) are approached, implying high density of non-radiative defects around x = 1. The diffusion of hydrogen in these films is also analyzed by Elastic Recoil Detection Analysis technique.

Soft X-ray irradiation effect on the surface and material properties of highly hydrogenated diamond-like carbon thin films

Surface and bulk properties' changes of a hydrogenated diamond-like carbon (H-DLC) film exposed to synchrotron radiation (SR) in the soft X-ray region were investigated by a nano-indenter, an atomic force microscope (AFM), and a combination of Rutherford Backscattering Spectroscopy (RBS) and Elastic Recoil Detection Analysis (ERDA) techniques. The surface of H-DLC films became flat and the hydrogen content of H-DLC films decreased with increasing SR dose. On the other hand, Vickers hardness showed the complicated dependency on the SR dose. It was found that modification processes of H-DLC films by SR exposure included three reactions: flattening on the surface, hydrogen desorption, and etching by SR exposure. • Soft X-ray irradiation effect on the surface and material properties of highly hydrogenated diamond-like carbon thin films was investigated. • The hydrogen content of H-DLC films decreased from » 50% to » 20% by the SR exposure. • The Vickers hardness of the films increased from » 500 HV to » 1600 HV. • The surface roughness and P-V of the H-DLC films decreased at lower SR doses. • The modification processes of H-DLC films by SR exposure include three reactions: flattening on the surface, hydrogen desorption, and etching.

Semi empirical formula for electronic stopping power determination of 24Mg, 27Al and 28Si ions crossing Formvar foil in the ion energy domain of LSS theory

We have determined continuous stopping power of heavy ions in thin Formvar foil for 28Si, 27Al and 24Mg ions over an energy range of (0.1–0.5)MeV/nucleon. Heavy Ions Elastic Recoil Detection Analysis (HI-ERDA) technique coupled with time of flight (ToF) spectrometer has been used to measure energy loss of charged particles in this thin absorber. Lindhard, Scharff and Schiott (LSS) theory compared with the corresponding determined stopping values in Formvar, shows significantly large deviations. However, a novel semi empirical expression has been proposed here and tested for better stopping power calculations at low velocity in the ion energy domain of LSS theory for 28Si, 27Al and 24Mg ions crossing thin Formvar foil. The results were compared to the obtained experimental stopping power data, predictions of LSS theory and also to those generated by SRIM-2010 computer code. The obtained results exhibit good agreement with experimental data.

Hydrogen absorption and desorption properties of Pd/Mg/Pd tri-layers prepared by magnetron sputtering

In this present work, a study on hydrogen absorption and desorption properties of Pd/Mg/Pd tri-layers, prepared by DC/RF magnetron sputtering has been conducted using XRD, FE-SEM and AFM. Hydrogenation of as-deposited Pd/Mg/Pd tri-layers was carried out at (50–150°C) temperatures in a fixed amount of hydrogen gas (100,000Pa). Hydrogen content in as-deposited and hydrogenated tri-layers have been estimated by Elastic Recoil Detection Analysis (ERDA) technique with 120MeV 107Ag+9 ions. The XRD study supported by ERDA data reveals the absorption of hydrogen in hydrogenated Pd/Mg/Pd tri-layers. The hydrogen desorption from Pd/Mg/Pd tri-layers is enhanced by “cooperative effect” caused by elastic interaction within interfacial region of Pd and Mg films. The maximum hydrogen absorption (8.4×1017 H atoms/cm2) has been observed at 125°C among all samples studied. Low desorption temperature (80°C) has been observed for Pd/Mg/Pd tri-layers.