Rutherford Backscattering Technique Research Articles

Characterization of agricultural biomass by particle induced x-ray emission and Rutherford backscattering techniques

Particle-induced x-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) techniques are non-destructive elemental analyses method with high sensitivity and capability for multi-element analysis in one spectrum. These techniques have not been used for the elemental characterization of biomass. So, this study characterized and evaluated elemental compositions of some selected agricultural biomass (Palm kernel shell (PKS), coconut shell (CS), cassava peel (CP), and Africa star apple seed shell (ASASS)) using combined PIXE and RBS. The results were compared with the ultimate analysis and optical-based techniques. Results from PIXE and RBS analysis confirm the presence of C, O, S, Na, Mg, P, Si, K, Ca, Fe, Cl, Al, Ti, Cu, and Zn in the tested biomass samples. Estimation of RBS accuracy by direct comparison with the ultimate analysis of some biomass samples showed a wide disparity of ±10.7% and ±2.57% in the RBS data for carbon and oxygen in PKS and a disparity of ±5.22% and ±0.55% in the RBS data for carbon and oxygen in coconut shell respectively. In the case of minor and trace element concentrations, estimated errors in the range of 1–3% and 2.68–4% were observed for optically based techniques compared with PIXE and RBS analysis, respectively.

Structural and Magnetic Specificities of Fe-B Thin Films Obtained by Thermionic Vacuum Arc and Magnetron Sputtering

Fe-B based compounds are of high interest due to their special properties and the wide range of involved applications. While B is the element that facilitates the increase in the hardness and the degree of wear resistance, it is also an effective glass former, controlling the formation of a much-desired amorphous structure with specific magnetic properties. Major difficulties related to the proper engineering of Fe-B thin films lay especially in their preparation under well-defined compositions, which in turn, should be accurately determined. The present study closely analyzes the morpho-structural and magnetic properties of thin coatings of Fe-B of approximately 100 nm thickness and with the nominal B content ranging from 5 at. % to 50 at. %. The comparison between films obtained by two preparation methods, namely, the thermionic vacuum arc and the magnetron sputtering is envisaged. Morpho-structural properties were highlighted using X-ray diffraction supplemented with X-ray reflectometry and scanning electron microscopy, whereas the elemental investigations were performed by X-ray dispersive spectroscopy and Rutherford back-scattering spectroscopy. The magnetic properties of the Fe-B layers were carefully investigated by the vectorial magneto-optic Kerr effect and conversion electron Mössbauer spectroscopy. The high capability of Mössbauer Spectroscopy to provide the phase composition and the B content in the formed Fe-B intermetallic films was proven, in correlation to Rutherford back-scattering techniques, and to explain their magnetic properties, including the magnetic texture of interest in many applications, in correlation with longitudinal magneto-optic-Kerr-effect-based techniques.

Nanostructured multi-layer MgF2/ITO coatings prepared via e-beam evaporation for efficient electromagnetic interference shielding performance

Nanostructured multi-layer MgF2/ITO coatings were deposited on glass substrate at various substrate temperatures (25 °C, 100 °C, 250 °C, 350 °C) for electromagnetic interference (EMI) shielding applications via e-beam evaporation. The as-deposited multi-layer MgF2/ITO coating was crystalline with crystallite size ∼25 nm and 20–30 nm for MgF2 and ITO, respectively. The coating thickness of MgF2 and ITO obtained via Rutherford backscattering technique (RBS) was determined to be 19 nm and 122 nm, respectively. Stoichiometry of the coatings was confirmed by RBS and EDS. The surface roughness depended on the substrate temperature during the deposition and decreased from approx. 10 nm at 25 °C to 4 nm at 350 °C. The highest value of optical transmittance in the visible range was obtained for MgF2/ITO at 25 °C reaching 94% at approx. 550 nm. The optical band gap of the coatings was determined to be in the range of 3.85–3.99 eV, which decreases with the increase of annealing temperature. The coatings showed significant conductivity suitable for EMI applications reaching 5.57 × 106 Ω−1 cm−1 for MgF2/ITO at 250 °C. The EMI shielding effectiveness of 68.1 dB was obtained for MgF2/ITO at 350 °C without scarifying the transmittance, which is suitable for aerospace and defense applications.

Band gap determination of chemically deposited Cu2S/Fe2O3 quaternary thin films

Quaternary thin films of Cu2S/Fe2O3 have been synthesized via simple, inexpensive and highly reproducible chemical bath deposition technique. The grown films were characterized with Rutherford backscattering technique (RBS), X-ray diffractometer (XRD), scanning electron microscope (SEM), and spectrophotometer for compositional, structural, morphological, and optical properties respectively. The multiple peaks exhibited by the various XRD patterns of the films showed that the films are polycrystalline while the SEM analysis showed an increase in grain size and uniformity of grain distribution as temperature increases. The absorbance (A), transmittance (T), absorption coefficient (  ), band gap (  g ), extinction coefficient (k), real ( r  ) and imaginary dielectric ( i  ) constants were modified by thermal annealing. The optical and solid state analysis for Cu2S/Fe2O3 thin films indicate that A ≤ 0.66, T ≤ 92 %,  ≤ 1.70 x 106m -1 ,  g increases from 3.75-3.85 eV, k ≤ 3.75, r  ≤ 8.5 and i  ≤ 2.05. The high transmittance in the infrared region of Cu2S-Fe2O3 thin films deposited suggest that the films can be used as coating materials for the construction of poultry houses in order to protect young chicks which have not developed protective thick feather from UV radiation while admitting the heating portion of electromagnetic spectrum into the house for warming young chicks. Based on the wide band gap exhibited by all the quaternary thin films, they are promising materials for window layers in solar cell fabrication and fabrication of optoelectronic devices, etc.

Enhanced photocatalytic activity of nZnO/n+Al:ZnO homojunction with an overlayer of Al2O3 nanoballs

This paper reports improvement in the degradation efficiency of ZnO for the organic dye methylene blue by constructing a homojunction of nZnO and n+Al doped ZnO with an overlayer of alumina nanoballs. The thin film junction is fabricated by the simple, cost-effective two stage electrochemical method of anodization followed by electrochemical doping at room temperature. Structural, optical, morphological and electrical analyses are done to elucidate the corresponding properties of each layer as well as of the junction. The compositional depth profile is obtained by the Rutherford backscattering technique. Valence band x-ray photoelectron spectroscopy in conjunction with optical data is used for designing the schematic of the junction formation. The rectification ratio of the thin film junction is determined to be ∼102 from voltage–current data.

Fabrication and Characterization of Clay-Polyethylene Composite Opted for Shielding of Ionizing Radiation

This study fabricated and characterized a self-sustaining hydrogenous content clay-polyethylene composite opted for ionizing radiation shielding. Composites designated A–G were fabricated each containing 0–30 wt% of recycled low density polyethylene (LDPE), respectively. To know the effects of the incorporated LDPE on the morphology, microstructural, compressive strength, thermal property and displacement effect on the vital elements were studied using scanning electron microscopy (SEM), X-ray diffractometry (XRD), universal mechanical testing machine, differential thermal analysis (DTA), Rutherford backscattering (RBS) technique and particle induced X-ray emission (PIXE), respectively. The bulk densities of the clay composites ranged between 1.341 and 2.030 g/cm3. The samples’ XRD analysis revealed similar patterns, with a sharp and prominent peak at angle 2θ equals ~26.11°, which matched with card number 16-0606 of the Joint Committee on Powder Diffraction Standards (JCPDS) that represents Aluminum Silicate Hydroxide (Al2Si2O5(OH)4), a basic formula for Kaolin clay. The compressive strength ranged between 2.52 and 5.53 MPa. The ratio of Si to Al in each composite is about 1:1. The dehydroxylation temperature for samples ranged between 443.23 °C and 555.23 °C.

Multi-layer MgF2/ITO coatings for electromagnetic interference shielding

Indium tin oxide (ITO) coatings have been found useful for diverse applications including electromagnetic interference (EMI) shielding for defense and aerospace purposes, solar cells, gas sensors, etc. However, the reliability, adhesion, transmittance and control of conductivity are some issues that need to be discussed for EMI shielding. Composite multi-layer coating of magnesium di-fluoride (MgF2) and ITO have been deposited on soda lime glass substrate using electron beam (e-beam) deposition technique at a substrate temperature of 350 °C and annealed in the temperature range of 200–500 °C for 1 h under vacuum. The deposited coatings have been characterized for structural, optical and electrical properties. The deposited coatings were crystalline with a crystallite size in the range of 20–30 nm for ITO and 15–20 nm for MgF2 coatings. The coating thickness of ITO and MgF2 determined by Rutherford backscattering technique were found to be 95 nm and 12 nm, respectively. The maximum transmittance in the visible range is ~92% for as-deposited and annealed multi-layer coatings. The band gap has been found in the range of 3.95–4.02 eV, which is suitable for EMI shielding effectiveness. Raman spectroscopy confirms quantum confinement in MgF2/ITO coatings. The electrical conductivity of as-deposited MgF2/ITO coating has been found to be 200 (Ω-cm)−1 which increased to a value of 1.002 x 103 (Ω-cm)−1 for the sample annealed at 500 °C under vacuum. The multi-layer coating annealed at 500 °C show good EMI shielding effectiveness of 50.4 dB without scarifying the transmittance.

Determination of the Oxygen Concentration in GDP Thin Films Using Rutherford Backscattering Spectroscopy

The oxygen concentration in the glow discharge polymer (GDP) capsule is one of the perturbations that most limit implosion quality. In order to investigate the feasibility of the Rutherford backscattering (RBS) technique for characterizing the oxygen concentration in a GDP capsule, the basic principle of RBS and the experimental conditions are introduced first. Then, the irradiation damage effect of incident ions on the GDP film is simulated numerically. The simulated results demonstrate that the GDP films will be damaged by the incident ions, and the vacancy damage dominates in irradiation modification. Finally, some GDP thin films are measured using RBS, and the oxygen concentration and its depth profile are obtained from the measured RBS spectrum. The simulated and experimental results prove that the oxygen concentration of GDP films can be measured precisely using RBS with an uncertainty of about 3.5%.

Structural, chemical and electrochemical studies of bismuth oxide thin films growth via Unbalanced Magnetron Sputtering

A study on the physical, chemical and electrochemical (properties) behavior of bismuth oxide thin films is presented in this work. Thin films were grown on 316 L stainless steel substrates via Unbalanced Magnetron Sputtering (UMS) in reactive phase, varying the DC power applied to the target between 20 and 80 W with 10 W step, keeping the gases flow constant at 9 sccm and the Ar/O2 ratio at 80:20. X-ray diffraction analysis was carried out for the structural characterization, showing that the crystallinity of the films strongly depends on the power of the discharge. The elemental chemical composition was determined using the Rutherford Backscattering (RBS) technique, making it possible to observe that the films were composed by a mixture of crystalline bismuth and possibly amorphous bismuth oxide. With this technique, the thickness of the coatings was measured, observing that this parameter increased from 200 to 700 nm as power values increased. Finally, the electrochemical analysis showed that corrosive behavior depends on the sample growth conditions and coatings thickness.

Influence of Lead Fluoride Substitution on the Physical Properties of ($$ {\text{Cu}}_{0.5} {\text{Tl}}_{0.5} $$)-1223 Phase

This work reveals the influence of lead fluoride on the physical properties of high-temperature superconductor samples \( \left( {{\text{Cu}}_{0.5 - x} {\text{Tl}}_{0.5} {\text{Pb}}_{x} } \right){\text{Ba}}_{2} {\text{Ca}}_{2} {\text{Cu}}_{3} {\text{O}}_{10 - \delta - y} {\text{F}}_{y} \), with (0.00 ≤ x ≤ 0.10). The samples under investigation were synthesized by solid-state reaction method at normal pressure. Ion beam analysis techniques were employed to determine the elemental content of the starting materials. The fluorine content “y” was estimated using the proton-induced gamma-ray emission technique by the aid of a 3 MeV proton beam. It was correlated to the oxygen content which was obtained using the Rutherford backscattering technique. Moreover, the samples were characterized using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and Fourier transform infrared (FTIR). The XRD data have indicated that the partial replacement of \( {\text{Cu}}^{2 + } \) ions by Pb2+ ions and oxygen by fluorine in the reservoir layer do not alter the tetragonal structure of the samples. On the other hand, the values of the lattice parameters a and c were found to be varied with x according to the difference in the ionic radii of \( {\text{Pb}}^{2 + } \;{\text{and}}\;{\text{Cu}}^{2 + } \) as well as to the oxygen content. SEM analysis has revealed that lead fluoride substitutions improve the inter-grains connectivity of the prepared samples. FTIR analysis has shown that the apical oxygen, planar and the oxygen in reservoirs layers, modes are observed around 415–524 cm−1, 564–579 cm−1 and 680 cm−1, respectively. Moreover, a shift in all absorption peaks was observed in the pure sample of (CuTl-1223) phase, and new peaks were appeared according to the values of x. The physical properties of the samples were investigated using electrical resistivity and ac magnetic susceptibility measurements at different values of the applied ac magnetic field. The granular response shows both inter-granular and intra-granular contributions. The values of the superconducting transition temperature (\( T_{\text{c}} \)) have shown an increase with x up to 0.06 wt% followed by a decrease with further increase in elements substitution.

Influence of barium doping on structural and magnetic properties of c-ZnO epitaxial layers grown on c-GaN/sapphire templates

Ba doped ZnO epitaxial layers (Ba:ZnO) with different Ba concentrations are grown on c-GaN/sapphire templates by chemical vapor deposition technique, where mixture of Ba and Zn powders is used as the source for these metals. Concentration of Ba in these layers is determined by secondary ion mass spectrometry and Rutherford backscattering techniques. X-ray diffraction studies demonstrates high epitaxial quality of these c-axis oriented films. c-lattice constant of these layers is found to increase with the Ba concentration, while a-lattice constant does not vary much. This suggests the strain developed in the film is uniaxial in nature. The width of the rocking curves taken at (0006) reflection is also found to increase with Ba concentration indicating the enhancement in the structural defects. This is also supported by the photoconductivity measurements. Thermally stimulated current spectroscopy reveals certain trap states with the activation energy of ∼ 192 meV in Ba doped layers. These layers also show ferromagnetic like behavior and the saturation magnetization is found to increase with the Ba-concentration, which may indicate the involvement of the generated defects in ferromagnetic ordering.

ZnO-Ge MULTILAYER THIN FILM STRUCTURES DEPOSITED BY THERMAL EVAPORATION TECHNIQUE

Zinc oxide and germanium multilayer films have been deposited on glass substrate using electron beam evaporation and resistive heating system, respectively, for alternate layers. The structural optical and electrical parameters have been investigated for the deposited films. The layer formation was confirmed by employing Rutherford back-scattering technique. Optical properties exhibit quantum confinement effect by showing the separate band gaps for ZnO and Ge. Electrical conductivity increases due to combined effect of all six layers (six alternate layers of Ge and ZnO).

Bandgap Engineering of Bilayer Ge/CdS Thin Films via Interlayer Diffusion under Different Annealing Temperatures

Bilayer thin films of Ge/CdS have been deposited on a glass substrate through thermal evaporation method. The obtained Ge/CdS samples were annealed at temperatures up to 400°C to observe the resulting effect on the structural changes in the film. The bandgap of the annealed films was found to increase with increasing annealing temperature which can be attributed to the increased interlayer diffusion. The interlayer diffusion was found to take effect above a temperature of 300°C which was confirmed by the Rutherford backscattering technique. Complementary XPS was done to investigate the surface stoichiometry of the bilayers.

Effect of high energy Ti9+ ion beam induced modifications in titanium dioxide and tin oxide nanocomposite thin films and detailed analysis of optical, structural and morphological properties

Ion beam irradiation technique plays an important role for modifications in optical, structural, and surface morphological properties of materials. The tin oxide and titanium dioxide nanocomposite thin films were synthesized using RF magnetron deposition technique followed by irradiation with 120 MeV Ti9+ swift heavy ions (SHI). The optical band gap for pristine and irradiated samples was calculated by UV–visible technique and the value of direct band gap decreased from 3.90 eV to 3.75 eV. The refractive index, optical conductivity, Urbach energy, skin depth and optical density have been calculated from the UV–Visible technique. Photoluminescence (PL) technique confirmed the presence of SnO2-TiO2 in the material by showing three standard peaks at 421 nm, 484 nm and 529 nm. Surface morphology of thin film was studied by Atomic Force Microscopy (AFM) technique and it showed grain size dependence on the ions irradiation fluence. The crystallite size was modified by SHI and studied by X-ray diffraction (XRD) technique. The crystallite size increased from 23.97 nm to 26.07 nm as calculated using Debye-Scherrer's formula and it also increased from 54.78 nm to 67.60 nm as obtained by Williamson-Hall equation. Based on the uniform deformation model (UDM), the strain and stress in thin films and dislocation density were calculated. The calculated roughness exponent and RMS roughness varied with irradiation fluence. Depth profiling and elemental analysis were observed by Rutherford Backscattering (RBS) technique.

An N-Heterocyclic Carbene Based Silver Precursor for Plasma-Enhanced Spatial Atomic Layer Deposition of Silver Thin Films at Atmospheric Pressure.

A new N-heterocyclic carbene (NHC)-based silver amide compound, 1,3-di-tert-butyl-imidazolin-2-ylidene silver(I) 1,1,1-trimethyl-N-(trimethylsilyl)silanaminide [(NHC)Ag(hmds)] was synthesized and analyzed by single-crystal X-ray diffraction, 1 H and 13 C NMR spectroscopy, as well as EI mass spectrometry, and subsequently evaluated for its thermal characteristics. This new halogen- and phosphine-free Ag atomic layer deposition (ALD) precursor was tested successfully for silver thin film growth in atmospheric pressure plasma enhanced spatial (APP-ALD). High-purity conductive Ag thin films with a low sheet resistance of 0.9 Ω/sq (resistivity: 10-5 Ωcm) were deposited at 100 °C and characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, optical transmittance, and Rutherford back-scattering techniques. The carbene-based Ag precursor and the new APP-ALD process are significant developments in the field of precursor chemistry as well as metal ALD processing.

Deposition of Ti6Al4V Thin Films by DC Magnetron Sputtering: Effect of the Current on Structural, Corrosion and Mechanical Properties

Ti6Al4V films have been prepared by DC magnetron sputtering technique at different currents (600, 700, 800 and 900 mA); target–substrate distance has been 3 cm. The depositions were carried out from Ti6Al4V alloy target. The deposition rate increases with increasing the current. The current effect on the crystalline quality and texture has been investigated by means of X-ray diffraction. β-Phase has been identified, and the grain size has been found to increase with increasing the current. The composition of the films has been determined by proton-induced X-ray emission and Rutherford backscattering technique. The Ti ratio was found to increase with current. The results obtained indicate that the TiAlV films by DC magnetron sputtering can inhibit the aggressive action of corrosion media. With increasing the current to improve film quality (bigger grain size), film Ti6Al4V/SS304 improved corrosion resistance for 304 substrate; microhardness was measured using Vickers method by applying 10 g load. Ti6Al4V film improves corrosion resistance and microhardness.

K-, L- and M-shell x-ray productions induced by xenon ions

Abstract K, L and M shell x-ray productions of elements from Cr to Bi induced by xenon ions with energies of 105, 131, 157, 183, and 210 MeV have been measured. The metal film thicknesses were determined with Rutherford backscattering technique using a 14N2 beam with energy of 14 MeV and the RUMP code. The molybdenum grid was applied as a beam monitor to measure the beam current integral on the target. The experimental results are compared with the predictions of the ECPSSR and PWBA models calculated with the ISICS code.

Development of a simple, low cost, indirect ion beam fluence measurement system for ion implanters, accelerators

We developed a simple, low cost user-friendly automated indirect ion beam fluence measurement system for ion irradiation and analysis experiments requiring indirect beam fluence measurements unperturbed by sample conditions like low temperature, high temperature, sample biasing as well as in regular ion implantation experiments in the ion implanters and electrostatic accelerators with continuous beam. The system, which uses simple, low cost, off-the-shelf components/systems and two distinct layers of in-house built softwarenot only eliminates the need for costly data acquisition systems but also overcomes difficulties in using properietry software. The hardware of the system is centered around a personal computer, a PIC16F887 based embedded system, a Faraday cup drive cum monitor circuit, a pair of Faraday Cups and a beam current integrator and the in-house developed software include C based microcontroller firmware and LABVIEW based virtual instrument automation software. The automatic fluence measurement involves two important phases, a current sampling phase lasting over 20–30 seconds during which the ion beam current is continuously measured by intercepting the ion beam and the averaged beam current value is computed. A subsequent charge computation phase lasting 700–900 seconds is executed making the ion beam to irradiate the samples and the incremental fluence received by the sampleis estimated usingthe latest averaged beam current value from the ion beam current sampling phase. The cycle of current sampling-charge computation is repeated till the required fluence is reached. Besides simplicity and cost-effectiveness, other important advantages of the developed system include easy reconfiguration of the system to suit customisation of experiments, scalability, easy debug and maintenance of the hardware/software, ability to work as a standalone system. The system was tested with different set of samples and ion fluences and the results were verified using Rutherford backscattering technique which showed the satisfactory functioning of the system. The accuracy of the fluence measurements is found to be less than 2% which meets the demands of the irradiation experiments undertaken using the developed set up. The system was incorporated for regular use at the existing ultra high vacuum (UHV) ion irradiation chamber of 1.7 MV Tandem accelerator and several ion implantation experiments on a variety of samples like SS304, D9, ODS alloys have been successfully carried out.

Optical and solid state characterizaion of chemically deposited CuO/PbS double layer thin film

Optical and solid state characteristics of novel CuO/PbS double layer thin films were studied. Rutherford backscattering (RBS) technique deciphered the thicknesses of the films as 650 nm, 471 nm and 482 nm for as-deposited, annealed at 473 K and 673 K respectively. The XRD analysis depicts increase in grain size and peak intensity as temperature increases. The results of optical characterization show that thermal annealing has profound effects on all the optical and solid state parameters investigated. The absorbance increased with increase in temperature exhibiting maximum for the film annealed at 673 K. The transmittance of the film samples showed a decreasing trend with increase in temperature exhibiting minimum for the film annealed at 673 K. The absorption coefficient increases from 0.001 × 106 m−1 to 0.006 × 106 m−1 for as-deposited, 0.0025 × 106 m−1 to 0.0175 × 106 m−1 for the annealed at 473 K and 0.003 × 106 m−1 to 0.020 × 106 m−1 for the annealed at 673 K. The extinction coefficient increased with increased in temperature exhibiting a maximum for the film annealed at 673 K. The refractive index, real and imaginary dielectric constant do not have a trend with increase in annealing temperature. Increase in annealing temperature lowers the band gap from 4.13 eV for the as-deposited to 4.05 eV and 3.90 eV for the annealed at 473 K and 673 K respectively. The wide- bandgap materials permits devices to operate at much higher voltages, frequencies and temperatures than convection semiconductor materials. Thus, this film could be used for high power applications, light-emitting diodes, transducers and window layers for solar cell fabrication.

Investigation of the Transverse Spread of Neodymium Ions Implanted in SOI

It is very important to consider the range distribution and transverse distribution of ions implanted into semiconductor materials in design and fabrication of semiconductor integration devices by ion implantation. The Nd (neodymium) ions with energy of 400 keV and dose of 2×1015 ions/cm2 were implanted into SOI (Silicon-on-insulator) samples at room temperature under the angles of 0°, 30° and 45°, respectively. The transverse distribution of 400 keV Nd ions implanted in SOI samples were measured by Rutherford backscattering technique. The measured results are compared with Monte Carlo code SRIM2012 predictions. It can be found that the experiment values were in good agreement with the prediction of SRIM2012 code.