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Rosario Pereiro - One of the best experts on this subject based on the ideXlab platform.
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pulsed radiofrequency glow discharge time of flight mass spectrometry Depth Profile analysis of multilayers on conductive and non conductive substrates
Spectrochimica Acta Part B: Atomic Spectroscopy, 2020Co-Authors: Lara Lobo, Beatriz Fernandez, Marta Aranaz, Andres Fernandez Lorenzo, Jose Ignacio Martincarbajo, Rosario PereiroAbstract:Abstract Combination of a pulsed glow discharge (PGD) source with time-of-flight mass spectrometry (TOFMS) enables for fast multielemental transient signals detection of solid samples. Such instrument is ideal for Depth profiling of layered materials with Depth resolution down to the low nm range. In this work, Depth Profile capabilities of radiofrequency (rf) PGD-TOFMS system have been investigated when dealing with thin layers (GexNi100-x/Ni/NdyNi100-y with total thicknesses between 15 nm and 75 nm) deposited on two substrates with different electrical properties (non-conductive glasses and silicon wafers). Attention has been paid towards the selection of the different PGD operational parameters aiming at achieving best instrument performance for each substrate in terms of Depth resolution of the thin coating layers. Particularly, the applied pulse width has proven to have a direct influence in the temporal regions (prepeak, plateau and afterglow) responsible of the analytical signals detected by TOFMS. Experimental results showed that shorter pulses (0.16 ms was finally selected) and periods (1.32 ms) allowed for better Depth Profile resolution of the layers deposited onto the glass substrate. However, such selection for the nonconductive substrate hindered obtaining analytical information from the prepeak and plateau regions. On the other hand, the effect of pulse width on Depth resolution was not so critical when coatings were deposited onto the silicon wafer.
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rapid evaluation of different perovskite absorber layers through the application of Depth Profile analysis using glow discharge time of flight mass spectrometry
Talanta, 2019Co-Authors: Beatriz Fernandez, Lara Lobo, Priyanka Tyagi, Vasil Stoichkov, Jeff Kettle, Rosario PereiroAbstract:Abstract Depth Profile analysis of perovskite absorber layers deposited onto glass substrates is investigated by radiofrequency pulsed glow discharge - time of flight mass spectrometry (rf-PGD-ToFMS). Elemental Depth Profiles obtained for perovskite films fabricated using a double-step deposition route with different precursors (methylammonium iodide and PbI2, PbCl2 or PbBr2) show varying distribution of the principle components depending on the precursors employed. Furthermore, the results show that rf-PGD-ToFMS allows to identify traces of residue solvent used in the initial film preparation (dimethyl sulphoxide or dimethylformamide) and to identify differences produced by film thickness and oxygen uptake caused by exposure to ambient conditions. The approach also enables inspection of the differences in elemental diffusion and the degradation processes. By using rf-PGD-ToFMS, no ultra-high-vacuum is needed for processing and rapid analysis of absorber films can be obtained in less than 40 s. The demonstration of such powerful analytical technique for obtaining Depth Profile information could enable groups in the field to better optimize processing conditions and enhance stability.
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evaluation of different strategies for quantitative Depth Profile analysis of cu nicu layers and multilayers via pulsed glow discharge time of flight mass spectrometry
Spectrochimica Acta Part B: Atomic Spectroscopy, 2017Co-Authors: Rocio Muniz, Lara Lobo, László Péter, Katalin Nemeth, Rosario PereiroAbstract:Abstract There is still a lack of approaches for quantitative Depth-profiling when dealing with glow discharges (GD) coupled to mass spectrometric detection. The purpose of this work is to develop quantification procedures using pulsed GD (PGD) - time of flight mass spectrometry. In particular, research was focused towards the Depth Profile analysis of Cu/NiCu nanolayers and multilayers electrodeposited on Si wafers. PGDs are characterized by three different regions due to the temporal application of power: prepeak, plateau and afterglow. This last region is the most sensitive and so it is convenient for quantitative analysis of minor components; however, major elements are often saturated, even at 30 W of applied radiofrequency power for these particular samples. For such cases, we have investigated two strategies based on a multimatrix calibration procedure: (i) using the afterglow region for all the sample components except for the major element (Cu) that was analyzed in the plateau, and (ii) using the afterglow region for all the elements measuring the ArCu signal instead of Cu. Seven homogeneous certified reference materials containing Si, Cr, Fe, Co, Ni and Cu have been used for quantification. Quantitative Depth Profiles obtained with these two strategies for samples containing 3 or 6 multilayers (of a few tens of nanometers each layer) were in agreement with the expected values, both in terms of thickness and composition of the layers.
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Depth Profile analysis of rare earth elements in corroded steels by pulsed glow discharge time of flight mass spectrometry
Journal of Analytical Atomic Spectrometry, 2017Co-Authors: Rocio Muniz, Lara Lobo, Timothy Kerry, Clint A Sharrad, Rosario PereiroAbstract:Depth profiling of 304L stainless steel surfaces exposed to rare earth nitrate solutions over varying time lengths has been undertaken using the recently commercialized “PP-TOFMS Plasma Profiling Spectrometer” by Horiba. This combines a pulsed glow discharge source with a time-of-flight mass spectrometer (TOFMS) which allows elemental Depth profiling with nanometric resolution of almost all elements of the periodic table. In this work special attention is paid first to the optimization of the new PP-TOFMS for Depth Profile analysis of low concentrations of rare earth elements (REE) in the samples. Sensitivity given in [(cps X × sputtering rate in μg s−1)/(μgX g−1)], being the concentration of the element X (μgX g−1) corrected by the abundance of the measured isotope, was in the order of 20 for all REEs under investigation. Moreover, a quantification strategy for these samples resembling the relative sensitive factors concept has been developed. Validation was done using a homogeneous reference material containing certified concentration values for La (6 ± 1 μg g−1), Ce (14 ± 1 μg g−1) and Nd (6 ± 1 μg g−1). Concentrations of 4 ± 1 μg g−1, 13 ± 1 μg g−1 and 5 ± 1 μg g−1 were calculated for La, Ce and Nd respectively with the proposed strategy. Quantitative Depth Profiles of the investigated samples have shown that the contaminants did not penetrate the substrate deeper than 80 nm even after a month of exposure to 12 M HNO3.
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Depth Profile analysis with glow discharge spectrometry
Journal of Analytical Atomic Spectrometry, 2017Co-Authors: Lara Lobo, Beatriz Fernandez, Rosario PereiroAbstract:Nowadays, glow discharge-optical emission spectrometry (GD-OES) and glow discharge-mass spectrometry (GD-MS) can be considered as two well established techniques for Depth profiling, offering practical interest to assist the synthesis optimization process and the quality control of materials coated with thin or thick layers. In this article, actual commercial instrumentation and Depth Profile quantification methods with these two analytical tools are first briefly reviewed. Afterwards particular attention is paid to the description of recent applications which show the almost unique capabilities of GD-OES and GD-MS for fast elemental quantitative Depth profiling of films going from an atomic layer up to more than a hundred micrometres. Moreover, some illustrative applications are shown for the characterization of organic films resorting to GD-OES and GD-MS.
Alfredo Sanzmedel - One of the best experts on this subject based on the ideXlab platform.
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Depth Profile analysis of amorphous silicon thin film solar cells by pulsed radiofrequency glow discharge time of flight mass spectrometry
Journal of the American Society for Mass Spectrometry, 2015Co-Authors: Aitor Alvareztoral, Rosario Pereiro, Alfredo Sanzmedel, Pascal Sanchez, Armando Menendez, Beatriz FernandezAbstract:Among the different solar cell technologies, amorphous silicon (a-Si:H) thin film solar cells (TFSCs) are today very promising and, so, TFSCs analytical characterization for quality control issues is increasingly demanding. In this line, Depth Profile analysis of a-Si:H TFSCs on steel substrate has been investigated by using pulsed radiofrequency glow discharge-time of flight mass spectrometry (rf-PGD-TOFMS). First, to discriminate potential polyatomic interferences for several analytes (e.g., 28Si+, 31P+, and 16O+) appropriate time positions along the GD pulse Profile were selected. A multi-matrix calibration approach, using homogeneous certified reference materials without hydrogen as well as coated laboratory-made standards containing hydrogen, was employed for the methodological calibration. Different calibration strategies (in terms of time interval selection on the pulse Profile within the afterglow region) have been compared, searching for optimal calibration graphs correlation. Results showed that reliable and fast quantitative Depth Profile analysis of a-Si:H TFSCs by rf-PGD-TOFMS can be achieved.
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Depth Profile characterization of zn tio2 nanocomposite films by pulsed radiofrequency glow discharge optical emission spectrometry
Talanta, 2011Co-Authors: Deborah Alberts, Beatriz Fernandez, Rosario Pereiro, Tania Frade, A Gomes, Maria Isabel Da Silva Pereira, Alfredo SanzmedelAbstract:Abstract In recent years particular effort is being devoted towards the development of radiofrequency (rf) pulsed glow discharges (GDs) coupled to optical emission spectrometry (OES) for Depth Profile analysis of materials with technological interest. In this work, pulsed rf-GD-OES is investigated for the fast and sensitive Depth characterization of Zn–TiO 2 nanocomposite films deposited on conductive substrates (Ti and steel). The first part of this work focuses on assessing the advantages of pulsed GDs, in comparison with the continuous GD, in terms of analytical emission intensities and emission yields. Next, the capability of pulsed rf-GD-OES for determination of thickness and compositional Depth Profiles is demonstrated by resorting to a simple multi-matrix calibration procedure. A rf forward power of 75 W, a pressure of 600 Pa, 10 kHz pulse frequency and 50% duty cycle were selected as GD operation parameters.Quantitative Depth Profiles obtained with the GD proposed methodology for Zn–TiO 2 nanocomposite films, prepared by the occlusion electrodeposition method using pulsed reverse current electrolysis, have proved to be in good agreement with results achieved by complementary techniques, including scanning electron microscopy and inductively coupled plasma-mass spectrometry. The work carried out demonstrates that pulsed rf-GD-OES is a promising tool for the fast analytical characterization of nanocomposite films.
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analytical performance of pulsed radiofrequency glow discharge optical emission spectrometry for bulk and in Depth Profile analysis of conductors and insulators
Journal of Analytical Atomic Spectrometry, 2011Co-Authors: Deborah Alberts, Beatriz Fernandez, Rosario Pereiro, Alfredo SanzmedelAbstract:Radiofrequency glow discharge (rf-GD) coupled to optical emission spectrometry (OES) has proved to be a powerful tool for the direct solid bulk materials and in-Depth Profile analysis. Rf-GD is generally operated in continuous mode, but the interest in pulsed (P) rf-GD is steadily increasing. So far, however, investigations to assess the analytical performance of rf-PGD-OES are scarce and systematic studies to analyse homogeneous and/or coated samples are still lacking. This work aims at critical comparison of the practical analytical performance characteristics of rf-GD-OES operated in continuous and pulsed modes. Pulsed rf-GD was carefully evaluated for the analysis of three conducting materials with different matrices (copper, steel and aluminium) and for bulk homogenous non-coated glasses of varying thicknesses (1, 1.8 and 2.8 mm). The comparison was performed in terms of crater shapes, sputtering rates and emission yields, demonstrating that increased emission yields could be obtained in pulsed mode working with small pulse widths (i.e. at high pulse frequency and relatively short duty cycle). Further, the potential of the pulsed rf-GDs has been studied also for Depth profiling analysis of a thin gold layer (∼30 nm) deposited on conductive and insulating substrates. An improvement in the Depth-resolution, under selected experimental conditions, was clearly observed. Finally, those observed advantages of pulsed rf-GD-OES were successfully tested by analysing real-life samples including commercial tinplates and a multilayered glass.
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quantitative Depth Profile analysis of metallic coatings by pulsed radiofrequency glow discharge optical emission spectrometry
Analytica Chimica Acta, 2011Co-Authors: Pascal Sanchez, Beatriz Fernandez, Rosario Pereiro, Armando Menendez, Jaime Orejas, Alfredo SanzmedelAbstract:In recent years particular effort is being devoted towards the development of pulsed GDs because this powering operation mode could offer important analytical advantages. However, the capabilities of radiofrequency (rf) powered glow discharge (GD) in pulsed mode coupled to optical emission spectrometry (OES) for real Depth Profile quantification has not been demonstrated yet. Therefore, the first part of this work is focussed on assessing the expected advantages of the pulsed GD mode, in comparison with its continuous mode counterpart, in terms of analytical emission intensities and emission yield parameters. Then, the capability of pulsed rf-GD-OES for determination of thickness and compositional Depth Profiles is demonstrated by resorting to a simple multi-matrix calibration procedure. A rf forward power of 50 W, a pressure of 600 Pa, 1000 Hz pulse frequency and 50% duty cycle were selected. The quantification procedure used was validated by analysing conductive layers of thicknesses ranging from a few tens of nanometer up to about 20 μm and varied compositions (hot-dipped zinc, galvanneal, back contact of thin film photovoltaic solar cells and tinplates).
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in Depth Profile analysis of filled alumina and titania nanostructured templates by radiofrequency glow discharge coupled to optical emission spectrometry
Analytical and Bioanalytical Chemistry, 2010Co-Authors: Deborah Alberts, Nerea Bordel, Rosario Pereiro, V Vega, V M Prida, Arne Bengtson, Alfredo SanzmedelAbstract:The development of highly ordered and self-assembled magnetic nanostructures such as arrays of Fe or Ni nanowires and their alloys is arousing increasing interest due to the peculiar magnetic properties of such materials at the nanoscale. These nanostructures can be fabricated using nanoporous anodic alumina membranes or self-assembled nanotubular titanium dioxide as templates. The chemical characterization of the nanostructured layers is of great importance to assist the optimization of the filling procedure or to determine their manufacturing quality. Radiofrequency glow discharge (RF-GD) coupled to optical emission spectrometry (OES) is a powerful tool for the direct analysis of either conducting or insulating materials and to carry out Depth Profile analysis of thin layers by multi-matrix calibration procedures. Thus, the capability of RF-GD-OES is investigated here for the in-Depth quantitative analysis of self-aligned titania nanotubes and self-ordered nanoporous alumina filled with arrays of metallic and magnetic nanowires obtained using the template-assisted filling method. The samples analysed in this work consisted of arrays of Ni nanowires with different lengths (from 1.2 up to 5 µm) and multilayer nanowires of alternating layers with different thicknesses (of 1–2 µm) of Ni and Au, or Au and FeNi alloy, deposited inside the alumina and titania membranes. Results, compared with other techniques such as scanning electron microscopy and energy-dispersive X-ray spectroscopy, show that the RF-GD-OES surface analysis technique proves to be adequate and promising for this challenging application.
Beatriz Fernandez - One of the best experts on this subject based on the ideXlab platform.
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pulsed radiofrequency glow discharge time of flight mass spectrometry Depth Profile analysis of multilayers on conductive and non conductive substrates
Spectrochimica Acta Part B: Atomic Spectroscopy, 2020Co-Authors: Lara Lobo, Beatriz Fernandez, Marta Aranaz, Andres Fernandez Lorenzo, Jose Ignacio Martincarbajo, Rosario PereiroAbstract:Abstract Combination of a pulsed glow discharge (PGD) source with time-of-flight mass spectrometry (TOFMS) enables for fast multielemental transient signals detection of solid samples. Such instrument is ideal for Depth profiling of layered materials with Depth resolution down to the low nm range. In this work, Depth Profile capabilities of radiofrequency (rf) PGD-TOFMS system have been investigated when dealing with thin layers (GexNi100-x/Ni/NdyNi100-y with total thicknesses between 15 nm and 75 nm) deposited on two substrates with different electrical properties (non-conductive glasses and silicon wafers). Attention has been paid towards the selection of the different PGD operational parameters aiming at achieving best instrument performance for each substrate in terms of Depth resolution of the thin coating layers. Particularly, the applied pulse width has proven to have a direct influence in the temporal regions (prepeak, plateau and afterglow) responsible of the analytical signals detected by TOFMS. Experimental results showed that shorter pulses (0.16 ms was finally selected) and periods (1.32 ms) allowed for better Depth Profile resolution of the layers deposited onto the glass substrate. However, such selection for the nonconductive substrate hindered obtaining analytical information from the prepeak and plateau regions. On the other hand, the effect of pulse width on Depth resolution was not so critical when coatings were deposited onto the silicon wafer.
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rapid evaluation of different perovskite absorber layers through the application of Depth Profile analysis using glow discharge time of flight mass spectrometry
Talanta, 2019Co-Authors: Beatriz Fernandez, Lara Lobo, Priyanka Tyagi, Vasil Stoichkov, Jeff Kettle, Rosario PereiroAbstract:Abstract Depth Profile analysis of perovskite absorber layers deposited onto glass substrates is investigated by radiofrequency pulsed glow discharge - time of flight mass spectrometry (rf-PGD-ToFMS). Elemental Depth Profiles obtained for perovskite films fabricated using a double-step deposition route with different precursors (methylammonium iodide and PbI2, PbCl2 or PbBr2) show varying distribution of the principle components depending on the precursors employed. Furthermore, the results show that rf-PGD-ToFMS allows to identify traces of residue solvent used in the initial film preparation (dimethyl sulphoxide or dimethylformamide) and to identify differences produced by film thickness and oxygen uptake caused by exposure to ambient conditions. The approach also enables inspection of the differences in elemental diffusion and the degradation processes. By using rf-PGD-ToFMS, no ultra-high-vacuum is needed for processing and rapid analysis of absorber films can be obtained in less than 40 s. The demonstration of such powerful analytical technique for obtaining Depth Profile information could enable groups in the field to better optimize processing conditions and enhance stability.
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Depth Profile analysis with glow discharge spectrometry
Journal of Analytical Atomic Spectrometry, 2017Co-Authors: Lara Lobo, Beatriz Fernandez, Rosario PereiroAbstract:Nowadays, glow discharge-optical emission spectrometry (GD-OES) and glow discharge-mass spectrometry (GD-MS) can be considered as two well established techniques for Depth profiling, offering practical interest to assist the synthesis optimization process and the quality control of materials coated with thin or thick layers. In this article, actual commercial instrumentation and Depth Profile quantification methods with these two analytical tools are first briefly reviewed. Afterwards particular attention is paid to the description of recent applications which show the almost unique capabilities of GD-OES and GD-MS for fast elemental quantitative Depth profiling of films going from an atomic layer up to more than a hundred micrometres. Moreover, some illustrative applications are shown for the characterization of organic films resorting to GD-OES and GD-MS.
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Depth Profile analysis of amorphous silicon thin film solar cells by pulsed radiofrequency glow discharge time of flight mass spectrometry
Journal of the American Society for Mass Spectrometry, 2015Co-Authors: Aitor Alvareztoral, Rosario Pereiro, Alfredo Sanzmedel, Pascal Sanchez, Armando Menendez, Beatriz FernandezAbstract:Among the different solar cell technologies, amorphous silicon (a-Si:H) thin film solar cells (TFSCs) are today very promising and, so, TFSCs analytical characterization for quality control issues is increasingly demanding. In this line, Depth Profile analysis of a-Si:H TFSCs on steel substrate has been investigated by using pulsed radiofrequency glow discharge-time of flight mass spectrometry (rf-PGD-TOFMS). First, to discriminate potential polyatomic interferences for several analytes (e.g., 28Si+, 31P+, and 16O+) appropriate time positions along the GD pulse Profile were selected. A multi-matrix calibration approach, using homogeneous certified reference materials without hydrogen as well as coated laboratory-made standards containing hydrogen, was employed for the methodological calibration. Different calibration strategies (in terms of time interval selection on the pulse Profile within the afterglow region) have been compared, searching for optimal calibration graphs correlation. Results showed that reliable and fast quantitative Depth Profile analysis of a-Si:H TFSCs by rf-PGD-TOFMS can be achieved.
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Depth Profile characterization of zn tio2 nanocomposite films by pulsed radiofrequency glow discharge optical emission spectrometry
Talanta, 2011Co-Authors: Deborah Alberts, Beatriz Fernandez, Rosario Pereiro, Tania Frade, A Gomes, Maria Isabel Da Silva Pereira, Alfredo SanzmedelAbstract:Abstract In recent years particular effort is being devoted towards the development of radiofrequency (rf) pulsed glow discharges (GDs) coupled to optical emission spectrometry (OES) for Depth Profile analysis of materials with technological interest. In this work, pulsed rf-GD-OES is investigated for the fast and sensitive Depth characterization of Zn–TiO 2 nanocomposite films deposited on conductive substrates (Ti and steel). The first part of this work focuses on assessing the advantages of pulsed GDs, in comparison with the continuous GD, in terms of analytical emission intensities and emission yields. Next, the capability of pulsed rf-GD-OES for determination of thickness and compositional Depth Profiles is demonstrated by resorting to a simple multi-matrix calibration procedure. A rf forward power of 75 W, a pressure of 600 Pa, 10 kHz pulse frequency and 50% duty cycle were selected as GD operation parameters.Quantitative Depth Profiles obtained with the GD proposed methodology for Zn–TiO 2 nanocomposite films, prepared by the occlusion electrodeposition method using pulsed reverse current electrolysis, have proved to be in good agreement with results achieved by complementary techniques, including scanning electron microscopy and inductively coupled plasma-mass spectrometry. The work carried out demonstrates that pulsed rf-GD-OES is a promising tool for the fast analytical characterization of nanocomposite films.
Takeo Ohsaka - One of the best experts on this subject based on the ideXlab platform.
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An XPS Depth-Profile study on electrochemically deposited TaO_ x
Journal of Solid State Electrochemistry, 2013Co-Authors: Zaenal Awaludin, Takeyoshi Okajima, Takeo OhsakaAbstract:Through the use of XPS and controlled Ar^+ etching, the surface composition and oxide species of tantalum oxides (TaO_ x ), which were electrodeposited on glassy carbon electrodes by cyclic voltammetric and constant-potential electrolyses, are quantified along the Depth Profile. Electrodeposition exhibits efficacy in depositing TaO_ x with a distribution of various TaO_ x : TaO, TaO_2, and Ta_2O_5. The distribution gradient from the outer surface of TaO_ x is such that Ta_2O_5 > TaO_2 > TaO. TaO is found to be the dominant species in the underlying layer of TaO_ x . Such a unique structure of the electrode surface is analogous to that of nanoparticles with a core–shell structure, with the core being suboxides and the surface being that of the saturated pentoxide, Ta_2O_5. The electrochemically induced nonhydrolytic condensation route is proposed to be capable of producing TaO_ x with a distribution gradient of Ta_2O_5, TaO_2, and TaO in the Depth direction.
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an xps Depth Profile study on electrochemically deposited tao x
Journal of Solid State Electrochemistry, 2013Co-Authors: James Guo Sheng Moo, Zaenal Awaludin, Takeyoshi Okajima, Takeo OhsakaAbstract:Through the use of XPS and controlled Ar+ etching, the surface composition and oxide species of tantalum oxides (TaOx), which were electrodeposited on glassy carbon electrodes by cyclic voltammetric and constant-potential electrolyses, are quantified along the Depth Profile. Electrodeposition exhibits efficacy in depositing TaOx with a distribution of various TaOx: TaO, TaO2, and Ta2O5. The distribution gradient from the outer surface of TaOx is such that Ta2O5 > TaO2 > TaO. TaO is found to be the dominant species in the underlying layer of TaOx. Such a unique structure of the electrode surface is analogous to that of nanoparticles with a core–shell structure, with the core being suboxides and the surface being that of the saturated pentoxide, Ta2O5. The electrochemically induced nonhydrolytic condensation route is proposed to be capable of producing TaOx with a distribution gradient of Ta2O5, TaO2, and TaO in the Depth direction.
Thomas Klunsner - One of the best experts on this subject based on the ideXlab platform.
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residual stress Depth profiling of a coated wc co hardmetal part ii of ii regression methods for stress Depth Profile reconstruction from diffraction data
International Journal of Refractory Metals & Hard Materials, 2019Co-Authors: H P Ganser, P Angerer, Thomas KlunsnerAbstract:Abstract Reconstruction of residual stress Depth Profiles from diffraction data depends crucially on the underlying assumptions regarding X-ray elastic constants, stress state, and generic shape of the stress Depth Profile. This article addresses two issues: first, how to account for X-ray elastic constants varying according to different crystallographic planes by rearranging the underlying equation system such that it becomes amenable to linear regression again; second, how to construct the residual stress Depth Profile via inverse Laplace transformation of a piecewise linear approximation function, thereby obtaining maximum flexibility in the description of the generic shape of the Profile. The methods are discussed by means of typical examples.