RBS Techniques Research Articles

Novel deposition method for gold and platinum nanoparticles on silicon substrates utilizing poly (ethylene glycol) 6000 for MEIS analysis

The use of nanoparticles has significantly increased in many areas, such as biomedical research, being highly useful as nanoprobes for imaging and as nanocarriers for drug delivery applications. Nevertheless, this potential can only be achieved with the correct characterization of the nanoparticles, since their size and shape can directly affect their biological behavior. In this study, we propose a novel approach for a monolayer deposition of gold and platinum nanoparticles on Si substrates suitable for medium energy ion scattering (MEIS) analysis. The samples were prepared using poly(ethylene glycol) 6000 (PEG 6000) as a coating agent for the substrates, utilizing a spin coater-a versatile, cost-effective, and practical technique. The samples were first analyzed with the RBS technique to assess the adhesion and the overlapping of the nanoparticles in the substrates coated with PEG 6000 and then characterized through the MEIS technique. The analysis through MEIS allowed the determination of the shape, size, and coverage area of the nanoparticles. Scanning and transmission electron microscopy were also performed on the samples, with the results corroborating the findings of the MEIS experiment. Together, the data obtained with microscopy and the MEIS technique suggests the effectiveness of the method in the production of monolayer samples.

Preparation of boron-doped diamond-like carbon films via enhanced-PECVD using an additional cathode

Boron-doped Diamond-Like Carbon (B:DLC) films with different concentrations of boron were produced in an Enhanced-PECVD reactor using trimethylborate (TMB) vapor as the boron source. An additional cathode system was incorporated inside the reactor to confine the plasma to grow B:DLC film on polished Ti-6Al-4 V and Silicon samples. The boron-containing coatings were evaluated and compared to a boron-free coating through several characterization techniques. Raman spectroscopy, Nano-hardness, XPS, RBS, and SEM techniques were employed to study the microstructure, hardness, chemical composition and bonding state, and morphology of the samples. Ball-on-disc tests were also conducted, using a tribometer to measure the friction coefficient and wear resistance. Boron was confirmed in the DLC film structure by XPS and RBS analyses. The XPS measurements showed that the boron bonding was accompanied by a higher content oxygen than carbon content, which increased with the TMB concentration. The sp3 content was evaluated, and the result showed a decrease of about 30 % with the higher solution concentration. As a consequence, the friction coefficient, wear, and hardness were affected. However, the adherence of the films was not compromised. Finally, our study indicated that the PECVD deposition system employing an additional cathode was suitable for the incorporation of boron into DLC films.

The use of simultaneous IBA techniques to fingerprint fine particle emissions during the Australian bushfire 2019-20 black summer event.

The outputs of the multi-elemental IBA techniques of PIXE, PIGE, RBS and PESA have been used as inputs to positive matrix factorisation source apportionment methods to quantify and fingerprint bushfire smoke during the catastrophic black summer bushfires of 2019-20 season in NSW, Australia.

Growth and characterization of electron beam evaporated NiO thin films for room temperature formaldehyde sensing

Herein, we report the formaldehyde gas sensing performance of NiO thin films deposited by the electron beam evaporation technique. NiO thin films were grown over glass substrates by the variation of deposition temperature from room temperature (RT) to 500⁰C. The structure, chemical composition and morphological studies were conducted by XRD, FESEM, EDS, AFM, XPS, RBS and HRTEM techniques. The XRD characterization revealed the formation of NiO in the polycrystalline phase with the face-centered cubic structure without impurity phases. The surface and morphological characterization confirmed the growth of the NiO thin layer and the homogeneous distribution of Ni and O elements on the surface of the films. The optical transmittance increased with the rise in deposition temperature. The optical band gap was estimated using Tauc relation and it was shown a decreasing trend with the rise in deposition temperature. The electrical characteristics of thin films were carried out using Hall measurements and presented. The developed gas sensors tested at room temperature have displayed good selectivity towards formaldehyde with a low detection limit of 10 ppm. The NiO thin film sensor prepared at a deposition temperature of 400⁰C has exhibited a short response and recovery time of 25 s and 9 s respectively towards 50 ppm concentration of formaldehyde. The detailed formaldehyde sensing mechanism for p-type NiO thin films was discussed. • E-beam evaporated NiO thin films were deposited by varying the substrate temperature. • The developed NiO films were tested to detect various VOCs at room temperature. • NiO sensor (400⁰C) has exhibited enhanced formaldehyde sensing performance. • The response and recovery times were determined to be 25 s and 9 s towards 50 ppm. • The sensing mechanism involved in redox reactions was projected.

Subsisting oxidizing material and parting agent selection in the fabrication of nuclear target

In order to perform certain heavy ion nuclear reaction experiments, the enriched targets of stable isotopes 61,62Ni, 116Sn, 154,144Sm and 142,148Nd have been fabricated by adapting physical vapour deposition technique at IUAC, New Delhi using a high vacuum evaporation chamber facility. Target materials are evaporated on a thin lower Z backing material. Fabrication of targets of materials which get readily oxidized poses lot of challenges. To avoid oxidation, appropriate capping along with backing is provided. To avoid contamination in the target, environmental condition and the proper selection of parting agent is also important. Role of encapsulation in minimizing the oxidation and the contamination level from parting agents in the targets is reported in this work. The thicknesses of the targets are verified using profilometer, α-energy loss technique. The purity of the fabricated targets is confirmed using RBS technique.

Security assessment for routing-based synthesis on cyberphysical MEDA-based digital microfluidic biochip

Cyberphysical microelectrode-dot-array (CP-MEDA)-based digital microfluidic biochip (DMFB) is attracting more attention than its predecessor of traditional DMFB. Conventional DMFBs are mostly unable to recover from the errors incurred at assay run time, and thus, it leads to unacceptable results. Recent studies have revealed the vulnerability of CP-DFMBs to detect malicious intrusions during its design or operational phase. In this paper, we have analysed such vulnerable scenarios that have been utilized by the routing-based-synthesis approach on a CP-MEDA. We have also depicted the mixing operations based on routing for ensuring better security measures. Various attacking scenarios have been demonstrated on a MEDA-based DMFB, and moreover, checkpoint-based intrusion detection method has been proposed for the RBS technique. The effectiveness of our approach is compared with the available benchmark assays. Our proposed method has shown significant improvement over the existing state-of-the-art procedures in terms of assay execution time and intrusion detection rate.

In-situ total Li depth profiling of solid state Li ion batteries under charging and discharging by means of transmission elastic recoil detection analysis with 5 MeV He2+ ions

Total Li depth profiles in Ti/NbO/LiPON/LMO batteries prepared on self-supporting Al and Ti substrates have been measured under charging and discharging by means of TERD and RBS techniques. Since TERD spectrum for as-received specimen of Ti/NbO/LiPON/LMO/Al showed that Li diffused from LMO to NbO during its preparation, at first, the discharging was performed by biasing at −0.5 V. Hereafter, the charging was performed at 3.2 V. TERD spectra under discharging clearly showed that Li in NbO was reduced and that in LMO and Al near LMO was enriched and more over Li in LiPON was reduced near NbO, while that was enriched near LMO. TERD spectra under charging also clearly showed ‘vice versa’ that Li in LMO and Al near LMO was reduced and that in NbO was enriched. Ti/NbO/LiPON/LMO/Ti was also charged and hereafter discharged. It was found that this battery was also rechargeable at one cycle.

Carbon-backed thin tin (116Sn) isotope target fabrication by physical vapor deposition technique

In nuclear reaction experiments, the thin targets are required. In the present work, 30 thin 116Sn targets were prepared using physical vapor deposition technique (preferable for thin film fabrication) on carbon backing with usage efficiency of 98%. The carbon-backed thin target films along with the parting agents are deposited on the particular substrates using a diffusion pump based coating unit. The thicknesses of the targets were verified using α-energy loss and RBS technique and they were in good agreement with each other. The purity of the target, verified using RBS, EDS and XRD techniques, were also tested with confirmation.

Crystallographic changes in electron pulse annealing of Ti-implanted GaP

ABSTRACT Gallium phosphide can be considered as a prospective material for impurity band solar cell (IBSC), if sufficient amount of an appropriate impurity (Ti in our case) is introduced to the material by e.g. ion implantation without distorting the crystallographic order, necessary to maintain the semiconducting properties of the host. In our experiments, the crystallographic order (damaged by ion implantation) is restored by electron pulse annealing (EPA). When the EPA process using subthreshold electron pulse energy density is studied by RBS technique, a peculiar electron-pulse induced lattice reconstruction is observed, consisting in growth of the damaged region beyond the range observed after ion implantation. This phenomenon is confirmed by transmission electron microscopy (TEM) results and interpreted in terms of melting nuclei formed around the implanted ions in a material with high sublimation pressure.

Carbon–titanium nanostructures: synthesis and characterization

C–Ti multilayer nanostructures were deposed by thermionic vacuum arc technology. The layers consisting of about 100 nm Carbon base layer and seven 40 nm alternatively Ti and C layers were deposed on Silicon substrates. On the other hand, in order to obtain C–Ti multilayer structures with variable thickness and different percentages in C and Ti of layers, a 20 nm thick C layer was first deposed on Si substrate and then seven Ti–C layers, each of these having thickness of up to 40 nm were deposed. To perform the successively layers with various thickness were changed the discharge parameters for C and Ti plasma sources to obtain the desirable thickness. By changing of substrate temperature between room temperature and 300 °C and on the other hand the bias voltage up to −700 V, different batches of samples were obtained for this study. To characterize properties of as prepared C–Ti multilayer structures were used electron microscopy techniques (TEM, STEM), Raman spectroscopy, RBS techniques and tribological measurements. To characterize the electrical conductive properties, the electrical surface resistance versus temperature have been measured, and then the electrical conductivity. Using the Wiedemann–Frantz law was calculated the thermal conductivity.

The new external ion-beam station at the Demokritos Tandem 5.5 MV accelerator: A unique analytical tool in the fields of cultural heritage and environmental science

At the 5.5 MV Tandem accelerator of the Institute of Nuclear Physics of NCSR Demokritos, Athens, a new external ion-beam set-up has been recently installed. The aim of this development was to establish a complete experimental set-up integrating the analytical capabilities of the PIXE, RBS and PIGE techniques, so that a complete elemental and near surface structural characterization of samples/artifacts to be attained in an almost non-destructive way and without any limitation concerning their size or conductive state. A careful 3D mechanical drawing optimized the experimental parameters of the set-up so that the special requirements imposed for optimum performance of the aforementioned techniques to be fulfilled.The first applications were focused in the quality control of tagged materials (technologically authentic replicas of attic ceramics and in coatings used by conservators for paintings).

Particle induced X-ray emission and Rutherford backscattering spectrometry for testing homogeneity of environmental certified reference material candidates

ABSTRACT Taking advantages of non-destructive techniques, between-bottles homogeneity tests were carried out in term of elemental composition of seven certified reference materials (CRMs) candidates using particle-induced X-ray emission technique (PIXE). A combination of PIXE and RBS techniques (Rutherford backscattering spectrometry) was also used for CRMs candidates having biological matrices. The CRMs candidates have the matrices of soil, sediment, dust, fish muscle, leaves and fruit, which will be certified for some major, minor and trace elements. One batch was produced for each CRM candidate, which included 80 bottles. Between-bottles homogeneity tests were performed for each CRM candidate using seven representative bottles. The repeatability of measurements by PIXE and RBS was examined. The relative standard deviations (RSD) and relative average deviation (RAD) of the elements contents were considered for variability assessment for both repeatability and between-bottles homogeneity. Al, Si and Fe showed good repeatability with RSD and RAD of <4%, while Mg, S, Cl, K, Ca, Mn and Sr showed RSD and RAD in the range of 4–10%. A content of one element in the examined CRMs candidates, with the exception of the date fruit, showed RSD and RAD of <5% indicating good between-bottles homogeneity. For date fruit, the relative error of all elements was <10%, with the exception of Si and Zn, while RAD of S, Cl and K were <10%.

TiO2 films by sol‐gel spin‐coating deposition with microbial antiadhesion properties

Intensive use of antibiotics induced adaptations in bacteria, which developed antibiotic resistance. This is becoming a serious health problem, particularly in the hospital, food industry, or public transport. It is also important to produce surfaces that not only are bactericidal but also prevent adhesion and the consequent biofilm formation, which can make the bacteria resistant to conventional disinfection methods. In this work, a simple and inexpensive method to obtain surfaces TiO2 film coated has been realized to prevent attachment and bacterial proliferation on surfaces. The synthesis and deposition procedure has been finalized to the realization of a uniform coating, whose physical, morphological, and structural features are suitable to inhibit the proliferation of the bacteria and in particular the adhesion of the biofilm. The suitability of the obtained coating has been attested by RBS, X‐ray diffraction (XRD), SEM, UV‐vis, and Raman techniques. The obtained coatings were homogeneous anatase titania films with an excellent adherence to the substrate and a transmittivity higher than 80% in the visible region. The results show that the TiO2 films considerably reduce microbial contamination on the surface (~98% reduction) feature that makes this coating suitable for antibacterial applications.

Ionoluminescence investigation of medieval Iranian luster glazed ceramics

Ionoluminescence behavior of some golden glazed ceramic samples from the historical (12th-13th century) cite of Tappeh Ghale, located in the central part of Iran, has been investigated. The required complementary information of the samples, including their elemental compositions and depth profiles, have been provided by means of PIXE and RBS techniques. The results reveal the sensitivity of IL spectra to the layered structure of the luster decorated samples. Indeed, luster layer acts as a mirror-like reflecting surface for the luminescence originating from the underneath layers. Interpretation of the luminescence bands was performed based on the experimental results of PIXE and RBS techniques and the available information in the literature. Some shifts in the peaks’ positions and also appearance of relatively high energy bands were observed.

Modelling the uptake of suspended materials and salts in nearshore waters by plastics using nuclear microscopy and depth profiling analytical tools

Plastic debris becomes a persistent contaminant in aquatic systems. The adherence of abiotic and biotic materials to plastics may potentiate structural changes and their degradation. How the major and minor elements present in sea water interact with polymers is largely unknown.Nuclear microprobe clusters PIXE and RBS techniques, which offer unique possibilities to characterize the materials deposited on the surface of plastics rejected to the aquatic environment. In particular, these techniques enable to examine the penetration of elements in deposits into the plastic structure. Food packaging polymers, high-density polyethylene (HDPE) and polyethylene terephthalate (PET) exposed to turbid water of the Tagus estuary were studied. The deposition mosaic contained clastic, biota and saline components. A major finding was the diffusion of the ion Cl- in the polymer matrix. This was possible by examining elemental profiles taken in transversal sections of the polymers. The depth structure of deposits was estimated using RBS and PIXE data applying the programs OMDAQ2007 and WiNDF, which illustrate the capabilities of these analytical tools in the micro-scale analysis of deposits. The results obtained pointed out for a multilayer depth structure which can decode the complex arrangement of cellular and sediment materials deposited on the polymer’s surface. In addition, it was possible to identify sources of uncertainties in simulating the interface and the changeable polymer matrix in sub-surface layers.

Fabrication and characterization of thin targets of nickel (61,62Ni) isotopes by physical vapour deposition technique for nuclear reaction studies

To perform nuclear reaction experiments at HIRA, IUAC, New Delhi, thin (100–150 μg/cm2) and pure 61,62Ni targets of uniform thickness are required. Self supporting targets are preferable for such case but, instead, carbon-backed isotopic targets are fabricated by adapting physical vapour deposition technique as it was comparatively more stable and consistent. Around 25 thin targets of both 61,62Ni isotopes are prepared using the limited amount of available enriched target material (less than 100 mg). The carbon-backed slides along with the parting agents are prepared using a diffusion pump based coating unit and the target material is deposited over the carbon-backed slides in the turbopump based coating unit. To obtain consistent and intact targets, some trials were done with deposited slides and was found that the material degrades in any of the slides when kept idle for few days. The thicknesses of the targets are verified using profilometer, α energy loss technique, and RBS technique. They were found to be in good agreement with each other using the three techniques. The purity and the uniformity of the fabricated targets are further confirmed after verification using the RBS, the EDS and the XRD techniques.

White matter tracts activated by successful subgenual cingulate deep brain stimulation

Plastic debris becomes a persistent contaminant in aquatic systems. The adherence of abiotic and biotic materials to plastics may potentiate structural changes and their degradation. How the major and minor elements present in sea water interact with polymers is largely unknown.Nuclear microprobe clusters PIXE and RBS techniques, which offer unique possibilities to characterize the materials deposited on the surface of plastics rejected to the aquatic environment. In particular, these techniques enable to examine the penetration of elements in deposits into the plastic structure. Food packaging polymers, high-density polyethylene (HDPE) and polyethylene terephthalate (PET) exposed to turbid water of the Tagus estuary were studied. The deposition mosaic contained clastic, biota and saline components. A major finding was the diffusion of the ion Cl- in the polymer matrix. This was possible by examining elemental profiles taken in transversal sections of the polymers. The depth structure of deposits was estimated using RBS and PIXE data applying the programs OMDAQ2007 and WiNDF, which illustrate the capabilities of these analytical tools in the micro-scale analysis of deposits. The results obtained pointed out for a multilayer depth structure which can decode the complex arrangement of cellular and sediment materials deposited on the polymer’s surface. In addition, it was possible to identify sources of uncertainties in simulating the interface and the changeable polymer matrix in sub-surface layers.

High resolution in situ Li depth profiling of thin films stacked Li ion batteries under charging conditions by means of TERD and RBS techniques with 5 MeV He+2 ion beam

The experimental results are reported on Ni/Si/LiPON/LCO/Pt/Ti and Au/Si/LiPON/LCO/Au batteries prepared on SiN and Al self-supporting films (LiPON = Li3.3PO3.8N0.2, LCO = LiCoO2) which have been in situ measured simultaneously by Transmission ERD and RBS techniques with 5 MeV He+2 ion beam, in order to understand Li transport from positive electrode (LCO) to negative electrode (Si) under charging and over-charging. It has been found on over-charging that for the former battery Li ions over-flowed out of Si reacts with Ni electrode in the follow direction, whereas for the latter battery Li once charged in Si returns back through LiPON to LCO in the counter direction and reacts with Al through intermediate Au. Quite different two transport phenomena of Li on over-charging are discussed in terms of transport process of Li through LiPON, the difference in Fermi energies of the metal electrodes at both sides of LCO/LiPON/Si and in contact potentials of Si with the metal electrodes.

Surface characteristic study of 130 keV argon ion implanted polypropylene polymer

ABSTRACTEffect of 130 keV argon ion implantation on surface morphology and structural properties of polypropylene (PP) at various fluences have been studied using RBS and UV-Visible Spectroscopy techniques. It has been found that there is an increase in the carbon concentration from 33 at.% (virgin) to 46 at.% in near surface region of PP at 1 × 1016 Ar+cm−2 as per RUMP simulation. Also, composition, depth profiling, projected range have been investigated. The observed surface morphological changes points towards the carbonization in the implanted layer of specimen. These structural modifications have further been correlated with the increase in optical absorption and flattening of absorption edge as observed by UV-Visible Spectroscopy.

High surface stability of magnetite on bi-layer Fe3O4/Fe/MgO(0 0 1) films under 1 MeV Kr+ ion irradiation

We investigate the stability of the bi-layer Fe3O4/Fe(0 0 1) films grown epitaxially on MgO(0 0 1) substrates with the layer thickness in the range of 25–100 nm upon 1 MeV Kr+ ion irradiation. The layer structure and layer composition of the films before and after ion irradiation were studied by XRR, RBS and RBS-C techniques. The interdiffusion and intermixing was analyzed. No visible change in the RBS spectra was observed upon irradiation with ion fluence below 1015 Kr cm−2. The bi-layer structure and the stoichiometric Fe3O4 layer on the surface were well preserved after Kr+ ion irradiation at low damage levels, although the strong intermixing implied a large interfacial (FexOy) and (Fe, Mg)Oy layer respective at Fe3O4–Fe and Fe–MgO interface. The high ion fluence of 3.8 × 1016 Kr cm−2 has induced a complete oxidization of the buffer Fe layer. Under such Kr fluence, the stoichiometry of the Fe3O4 surface layer was still preserved indicating its high stability. The entire film contains FexOy -type composition at ion fluence large than 5.0 × 1016 Kr cm−2.