TY - JOUR A1 - Abou-Ras, D. A1 - Caballero, R. A1 - Fischer, C.-H. A1 - Kaufmann, C.A. A1 - Lauermann, I. A1 - Mainz, R. A1 - Mönig, H. A1 - Schöpke, A. A1 - Stephan, C. A1 - Streeck, C. A1 - Schorr, S. A1 - Eicke, A. A1 - Döbeli, M. A1 - Gade, B. A1 - Hinrichs, J. A1 - Nunney, T. A1 - Dijkstra, H. A1 - Hoffmann, V. A1 - Klemm, D. A1 - Efimova, V. A1 - Bergmaier, A. A1 - Dollinger, G. A1 - Wirth, Thomas A1 - Unger, Wolfgang A1 - Rockett, A.A. A1 - Perez-Rodriguez, A. A1 - Alvarez-Garcia, J. A1 - Izquierdo-Roca, V. A1 - Schmid, T. A1 - Choi, P.-P. A1 - Müller, M. A1 - Bertram, F. A1 - Christen, J. A1 - Khatri, H. A1 - Collins, R.W. A1 - Marsillac, S. A1 - Kötschau, I. T1 - Comprehensive comparison of various techniques for the analysis of elemental distributions in thin films N2 - The present work shows results on elemental distribution analyses in Cu(In,Ga)Se2 thin films for solar cells performed by use of wavelength-dispersive and energy-dispersive X-ray spectrometry (EDX) in a scanning electron microscope, EDX in a transmission electron microscope, X-ray photoelectron, angle-dependent soft X-ray emission, secondary ion-mass (SIMS), time-of-flight SIMS, sputtered neutral mass, glow-discharge optical emission and glow-discharge mass, Auger electron, and Rutherford backscattering spectrometry, by use of scanning Auger electron microscopy, Raman depth profiling, and Raman mapping, as well as by use of elastic recoil detection analysis, grazing-incidence X-ray and electron backscatter diffraction, and grazing-incidence X-ray fluorescence analysis. The Cu(In,Ga)Se2 thin films used for the present comparison were produced during the same identical deposition run and exhibit thicknesses of about 2 µm. The analysis techniques were compared with respect to their spatial and depth resolutions, measuring speeds, availabilities, and detection limits. KW - Elemental distributions KW - Comparison KW - Depth profiling KW - Chemical mapping KW - Thin films KW - Solar cells KW - Chalcopyrite-type KW - Cu(In,Ga)Se2 PY - 2011 U6 - https://doi.org/10.1017/S1431927611000523 SN - 1431-9276 SN - 1435-8115 VL - 17 IS - 5 SP - 728 EP - 751 PB - Cambridge University Press CY - New York, NY AN - OPUS4-24506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kim, K. J. A1 - Kim, A. S. A1 - Jang, J. S. A1 - Suh, J. K. A1 - Wirth, Thomas A1 - Hodoroaba, Vasile-Dan A1 - Unger, Wolfgang A1 - Araujo, J. R. A1 - Archanjo, B. S. A1 - Galhardo, C. E. A1 - Damasceno, J. A1 - Achete, C. A. A1 - Wang, H. A1 - Wang, M. A1 - Bennett, J. A1 - Simons, D. A1 - Kurokawa, A. A1 - Terauchi, S. A1 - Fujimoto, T. A1 - Streeck, C. A1 - Beckhoff, B. A1 - Spencer, S. A1 - Shard, A. T1 - Measurement of mole fractions of Cu, In, Ga and Se in Cu(In,Ga)Se2 films N2 - CCQM key comparison K-129 for the quantitative analysis of Cu(In,Ga)Se2 (CIGS) films has been performed by the Surface Analysis Working Group (SAWG) of the Consultative Committee for Amount of Substance (CCQM). The objective of this key comparison is to compare the equivalency of the National Metrology Institutes (NMIs) and Designated Institutes (DIs) for the measurement of mole fractions of Cu, In, Ga and Se in a thin CIGS film. The measurand of this key comparison is the average mole fractions of Cu, In, Ga and Se of a test CIGS alloy film in the unit of mole fraction (mol/mol). Mole fraction with the metrological unit of mol/mol can be practically converted to atomic fraction with the unit of at%. In this key comparison, a CIGS film with certified mole fractions was supplied as a reference specimen to determine the relative sensitivity factors (RSFs) of Cu, In, Ga and Se. The mole fractions of the reference specimen were certified by isotope dilution - inductively coupled plasma/mass spectrometry (ID-ICP/MS) and are traceable to the SI. A total number counting (TNC) method was recommended as a method to determine the signal intensities of the constituent elements acquired in the depth profiles by Secondary Ion Mass Spectrometry (SIMS), X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). Seven NMIs and one DI participated in this key comparison. The mole fractions of the CIGS films were measured by depth profiling based-SIMS, AES and XPS. The mole fractions were also measured by non-destructive X-Ray Fluorescence (XRF) Analysis and Electron Probe Micro Analysis (EPMA) with Energy Dispersive X-ray Spectrometry (EDX). In this key comparison, the average degrees of equivalence uncertainties for Cu, In, Ga and Se are 0.0093 mol/mol, 0.0123 mol/mol, 0.0047 mol/mol and 0.0228 mol/mol, respectively. These values are much smaller than that of Fe in a Fe-Ni alloy film in CCQM K-67 (0.0330 mol/mol). This means that the quantification of multi-element alloy films is possible by depth profiling analysis using the TNC method. KW - CIGS KW - Key comparison KW - CCQM KW - SIMS KW - XPS KW - AES KW - XRF KW - EPMA PY - 2016 UR - http://iopscience.iop.org/article/10.1088/0026-1394/53/1A/08011 U6 - https://doi.org/10.1088/0026-1394/53/1A/08011 SN - 0026-1394 SN - 1681-7575 VL - 53, Technical Supplement SP - Article 08011, 1 EP - 19 PB - IOP Publishing AN - OPUS4-38110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kim, K.J. A1 - Jang, J. S. A1 - Kim, A. S. A1 - Suh, J.K. A1 - Chung, Y.-D. A1 - Hodoroaba, Vasile-Dan A1 - Wirth, Thomas A1 - Unger, Wolfgang A1 - Kang, H. J. A1 - Popov, O. A1 - Popov, I. A1 - Kuselman, I. A1 - Lee, Y. H. A1 - Sykes, D. E. A1 - Wang, M. A1 - Wang, H. A1 - Ogiwara, T. A1 - Nishio, M. A1 - Tanuma, S. A1 - Simons, D. A1 - Szakal, C. A1 - Osborn, W. A1 - Terauchi, S. A1 - Ito, M. A1 - Kurokawa, A. A1 - Fujiimoto, T. A1 - Jordaan, W. A1 - Jeong, C. S. A1 - Havelund, R. A1 - Spencer, S. A1 - Shard, A. A1 - Streeck, C. A1 - Beckhoff, B. A1 - Eicke, A. A1 - Terborg, R. T1 - CCQM pilot study P-140: Quantitative surface analysis of multi-element alloy films N2 - A pilot study for the quantitative surface analysis of multi-element alloy films has been performed by the Surface Analysis Working Group (SAWG) of the Consultative Committee for Amount of Substance (CCQM). The aim of this pilot study is to ensure the equivalency in the measurement capability of national metrology institutes for the quantification of multi-element alloy films. A Cu(In,Ga)Se2 (CIGS) film with non-uniform depth distribution was chosen as a representative multi-element alloy film. The atomic fractions of the reference and the test CIGS films were certified by isotope dilution - inductively coupled plasma/mass spectrometry. A total number counting (TNC) method was used as a method to determine the signal intensities of the constituent elements, which are compared with their certified atomic fractions. The atomic fractions of the CIGS films were measured by various methods, such as Secondary Ion Mass Spectrometry (SIMS), Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS), X-Ray Fluorescence (XRF) analysis and Electron Probe Micro Analysis (EPMA) with Energy Dispersive X-ray Spectrometry (EDX). Fifteen laboratories from eight National Metrology Institutes (NMIs), one Designated Institute (DI) and six non-NMIs participated in this pilot study. Although the average atomic fractions of 18 data sets showed rather poor relative standard deviations of about 5.5 % to 6.8 %, they were greatly improved to about 1.5 % to 2.2 % by excluding 5 strongly deviating data sets from the average atomic fractions. In this pilot study, the average expanded uncertainties of SIMS, XPS, AES, XRF and EPMA were 3.84%, 3.68%, 3.81%, 2.88% and 2.90%, respectively. These values are much better than those in the key comparison K-67 for composition of a Fe-Ni alloy film. As a result, the quantification of CIGS films using the TNC method was found to be a good candidate as a subject for a CCQM key comparison. KW - CCQM KW - Pilot study KW - Surface analysis KW - Alloy films KW - CIGS PY - 2015 U6 - https://doi.org/10.1088/0026-1394/52/1A/08017 SN - 0026-1394 SN - 1681-7575 VL - 52 IS - Technical Supplement SP - Article 08017 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-35306 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Förste, F. A1 - Bauer, L. A1 - Streeck, C. A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Kadow, D. A1 - Keil, C. A1 - Mantouvalou, I. T1 - Quantitative Analysis and 2D/3D Elemental Imaging of Cocoa Beans Using X‑ray Fluorescence Techniques N2 - As an important raw material for the confectionery industry, the cocoa bean (Theobroma cacao L.) has to meet certain legal requirements in terms of food safety and maximum contaminant levels in order to enter the cocoa market. Understanding the enrichment and distribution of essential minerals but also toxic metals is of utmost importance for improving the nutritional quality of this economically important raw food material. We present three X-ray fluorescence (XRF) techniques for elemental bio-imaging of intact cocoa beans and one additional XRF technique for quantitative analysis of cocoa pellets. The interrelation of all the methods presented gives a detailed picture of the content and 3D-resolved distribution of elements in complete cocoa beans for the first time. KW - BAMline KW - Synchrotron KW - XRF KW - CXC KW - Cocoa PY - 2023 U6 - https://doi.org/10.1021/acs.analchem.2c05370 VL - 95 SP - 5627 EP - 5635 PB - ACS Publications AN - OPUS4-57832 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streeck, C. A1 - Nutsch, A. A1 - Dietrich, P. A1 - Fischer, Tobias A1 - Grötzsch, D. A1 - Nietzold, Carolin A1 - Malzer, W. A1 - Rurack, Knut A1 - Beckhoff, B. A1 - Unger, Wolfgang T1 - Characterization of bio-molecular surfaces and liquids by means of reference-free X-ray spectrometry N2 - An increasing field of application for X-ray spectrometry and related analysis techniques is the investigation of tailor made functional surfaces modified by organic molecules. For a detailed understanding and further development of such functionalized surfaces, a quantitative determination of the surface density of molecular species or even specific functional groups is required. By means of reference-free X-Ray Fluorescence (XRF) spectrometry such customized surfaces can be analyzed quantitatively, when using specific marker elements. A chemical analysis of molecular bonds can be accomplished by X-Ray Absorption Spectroscopy in the Near-Edge region (NEXAFS). Especially in the soft X-ray range an access to relevant light elements like carbon C, nitrogen N and oxygen O is possible. Especially, the characterization of liquids and solid-liquid interfaces aiming at the determination of bio-molecular moieties (functional groups) is of great interest. The characterization of such systems requires the analysis of bio-molecules in their liquid environment. For the understanding of (biomolecular) reactions and binding processes the verification and quantification of biomolecule immobilization is essential. However, the analysis in the soft-X-ray range involves a higher experimental effort. In this contribution various successful applications of the characterizations of organofunctionalized surfaces, solid-liquid interfaces and liquids containing bio-molecular species by means of reference-free X-ray spectrometry will be presented. The experiments were performed at the plane-grating monochromator beamline (PGM-U49) in the soft X-ray range at the synchrotron radiation facility BESSY II. Using calibrated instrumentation and a quantification approach based on atomic fundamental parameters a quantitative access without any calibration sample or reference material is possible. In a complementary analysis by X-Ray Photoelectron Spectroscopy (XPS) and fluorescence measurements based on laserexcitation in the optical light spectrum the functional-group density of silane monolayers were determined. Here, the nitrogen atoms of the head-group of the label molecule employed could be used as specific marker for the reference-free quantitative XRF analysis and is used for traceable calibration of XPS and fluorescence spectroscopy. Furthermore, a novel UHV-compatible liquid-cell developed to investigate liquids and solidliquid interfaces will be presented. Protein attachment at the solid-liquid interface was investigated by detection of the characteristic N1s→π*(O=C-N) amide bond resonance in the N K-edge NEXAFS by using ultra-thin epoxy-functionalized SiC-windows. T2 - European Conference on X-Ray Spectrometry (EXRS) CY - Gothenburg, Sweden DA - 19.06.2016 KW - Bio-molecular surfaces KW - NEXAFS KW - XPS KW - XRS PY - 2016 AN - OPUS4-36965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streeck, C. A1 - Nutsch, A. A1 - Weser, J. A1 - Fischer, Tobias A1 - Dietrich, Paul A1 - Rurack, Knut A1 - Unger, Wolfgang A1 - Beckhoff, B. T1 - Reference-free total reflection X-ray fluorescence analysis for quantification of functional groups on surfaces for bioanalytical applications T2 - 6th Joint BER II and BESSY II User Meeting of HZB CY - Berlin, Germany DA - 2014-12-04 PY - 2014 AN - OPUS4-32390 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dietrich, Paul A1 - Streeck, C. A1 - Glamsch, Stephan A1 - Ehlert, Christopher A1 - Lippitz, Andreas A1 - Nutsch, A. A1 - Kulak, N. A1 - Beckhoff, B. A1 - Unger, Wolfgang T1 - Quantification of silane molecules on oxidized silicon: Are there options for a traceable and absolute determination? N2 - Organosilanes are used routinely to functionalize various support materials for further modifications. Nevertheless, reliable quantitative information about surface functional group densities after layer formation is rarely available. Here, we present the analysis of thin organic nanolayers made from nitrogen containing silane molecules on naturally oxidized silicon wafers with reference-free total reflection X-ray fluorescence (TXRF) and X-ray photoelectron spectroscopy (XPS). An areic density of 2−4 silane molecules per nm2 was calculated from the layer’s nitrogen mass deposition per area unit obtained by reference-free TXRF. Complementary energy and angle-resolved XPS (ER/ARXPS) in the Si 2p core-level region was used to analyze the outermost surface region of the organic (silane layer)−inorganic (silicon wafer) interface. Different coexisting silicon species as silicon, native silicon oxide, and silane were identified and quantified. As a result of the presented proof-of-concept, absolute and traceable values for the areic density of silanes containing nitrogen as intrinsic marker are obtained by calibration of the XPS methods with reference-free TXRF. Furthermore, ER/AR-XPS is shown to facilitate the determination of areic densities in (mono)layers made from silanes having no heteroatomic marker other than silicon. After calibration with reference-free TXRF, these areic densities of silane molecules can be determined when using the XPS component intensity of the silane’s silicon atom. PY - 2015 U6 - https://doi.org/10.1021/acs.analchem.5b02846 SN - 0003-2700 SN - 1520-6882 VL - 87 IS - 19 SP - 10117 EP - 10124 PB - American Chemical Society CY - Washington, DC AN - OPUS4-34796 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streeck, C. A1 - Grötzsch, D. A1 - Witte, K. A1 - Dietrich, Paul A1 - Malzer, W. A1 - Nutsch, A. A1 - Stiel, H. A1 - Unger, Wolfgang A1 - Kanngießer, B. A1 - Beckhoff, B. T1 - A liquid cell for the analysis of biomolecules (e.g. proteins, chlorophyll) using soft X-ray excitation N2 - For versatile applications, including vacuum instrumentation, a liquid cell was developed. Using ultra-thin windows, this cell enables X-ray Absorption spectrometry in the soft X-ray range which is in particular interesting for the analysis of organic molecules in liquids or at the solid-liquid interface. NEXAFS of a protein at N K-edge and of chlorophyll a at Mg K-edge is demonstrated. T2 - 8th Jouint BER II and BESSY II User Meeting CY - Berlin, Germany DA - 7.12.2016 KW - XAS KW - NEXAFS KW - Liquid cell KW - Chlorophyll PY - 2016 AN - OPUS4-38711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Streeck, C. A1 - Wirth, Thomas A1 - Unger, Wolfgang A1 - Beckhoff, B. T1 - Qualifying calibration samples for advanced thin film materials characterisation N2 - In this article the question of the certification of calibration samples for the characterisation of advanced thin film materials is addressed within the framework of reliable process control or quality management purposes. Reference measurement techniques can be used in order to address the gap in appropriate certified reference materials (CRMs) for thin film analyses. They allow for qualifying out-of-production samples originating from an operating production line as calibration samples. As a template for this procedure, CIGS [Cu(In,Ga)Se2] layers, that are absorber layers for high efficiency thin-film solar cells, have been used for establishing and validating reference-free X-ray fluorescence (XRF) analysis and Auger-electron spectroscopy (AES) as reference measurement techniques. The focus was on determining the average mole fractions in the CIGS layers obtaining results traceable to the SI unit system. Reference-free XRF is physically traceable and is based upon radiometrically calibrated instrumentation and knowledge of atomic fundamental data. Sputter-assisted AES can be established as a chemically traceable method after careful calibration using a certified reference material (CRM) based on a total number counting method. KW - CIGS KW - X-ray fluorescence (XRF) KW - Auger-electron spectroscopy (AES) PY - 2018 UR - https://www.spectroscopyeurope.com/article/qualifying-calibration-samples-advanced-thin-film-materials-characterisation VL - 30 IS - 1 SP - 11 EP - 14 PB - John Wiley & Sons Ltd CY - Chichester, West Sussex PO19 8SQ, UK AN - OPUS4-44260 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fischer, Tobias A1 - Dietrich, Paul A1 - Streeck, C. A1 - Ray, S. A1 - Nutsch, A. A1 - Shard, A. A1 - Beckhoff, B. A1 - Unger, Wolfgang A1 - Rurack, Knut T1 - Quantification of variable functional-group densities of mixed-silane monolayers on surfaces via a dual-mode fluorescence and XPS label N2 - The preparation of aminated monolayers with a controlled density of functional groups on silica surfaces through a simple vapor deposition process employing different ratios of two suitable monoalkoxysilanes, (3-aminopropyl)diisopropylethoxysilane (APDIPES) and (3-cyanopropyl)dimethylmethoxysilane (CPDMMS), and advances in the reliable quantification of such tailored surfaces are presented here. The one-step codeposition process was carried out with binary silane mixtures, rendering possible the control over a wide range of densities in a single step. In particular, APDIPES constitutes the functional silane and CPDMMS the inert component. The procedure requires only small amounts of silanes, several ratios can be produced in a single batch, the deposition can be carried out within a few hours and a dry atmosphere can easily be employed, limiting self-condensation of the silanes. Characterization of the ratio of silanes actually bound to the surface can then be performed in a facile manner through contact angle measurements using the Cassie equation. The reliable estimation of the number of surface functional groups was approached with a dual-mode BODIPY-type fluorescence label, which allows quantification by fluorescence and XPS on one and the same sample. We found that fluorescence and XPS signals correlate over at least 1 order of magnitude, allowing for a direct linking of quantitative fluorescence analysis to XPS quantification. Employment of synchrotron-based methods (XPS; reference-free total reflection X-ray fluorescence, TXRF) made the traceable quantification of surface functional groups possible, providing an absolute reference for quantitative fluorescence measurements through a traceable measurement chain. KW - Oberflächenanalytik KW - Fluoreszenz KW - XPS KW - TXRF KW - Funktionelle Gruppen PY - 2015 U6 - https://doi.org/10.1021/ac503850f SN - 0003-2700 SN - 1520-6882 VL - 87 IS - 5 SP - 2685 EP - 2692 PB - American Chemical Society CY - Washington, DC AN - OPUS4-34470 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streeck, C. A1 - Nutsch, A. A1 - Beckhoff, B. A1 - Rurack, Knut A1 - Fischer, Tobias A1 - Dietrich, Paul A1 - Unger, Wolfgang T1 - Reference-free quantification of functional groups on surfaces for bioanalytical applications by total reflection X-ray fluorescence analysis N2 - For the development of biosensors or microarrays in biotechnology functionalized surfaces e.g. aminated glass surfaces can be used. Knowledge of the quantity of primary reactive groups on such surfaces is indispensable for a defined secondary modification with commonly biochemical entities, eventually resulting in more reliably tailored surfaces with better controlled properties. Here, we investigated aminated glass surfaces with varying densities of amino groups prepared from binary mixtures of silanes. Subsequent labeling of the amino groups with a fluorophore containing a high number of fluorine atoms allows complementary quantification of the organic groups by optical fluorescence spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and traceable Total-Reflection X-ray Fluorescence analysis (TXRF). Reference-free TXRF with soft X-ray excitation determines the mass deposition of elements such as carbon, nitrogen and fluorine, yielding the areal density of primary functional groups on the surface. The TXRF-measurements were performed at the PTB beamline for undulator radiation at the electron storage ring BESSY II which provides monochromatic soft X-rays with high spectral purity and photon flux. This approach allows the calibration of optical fluorescence spectroscopy and XPS to deliver traceable quantitative data. T2 - European Conference on X-Ray Spectrometry (EXRS-2014) CY - Bologna, Italien DA - 2014-06-15 PY - 2014 AN - OPUS4-34664 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grötzsch, D. A1 - Streeck, C. A1 - Nietzold, Carolin A1 - Malzer, W. A1 - Mantouvalou, I. A1 - Nutsch, A. A1 - Dietrich, Paul A1 - Unger, Wolfgang A1 - Beckhoff, B. A1 - Kanngießer, B. T1 - A sealable ultrathin window sample cell for the study of liquids by means of soft X-ray spectroscopy N2 - A new sample cell concept for the analysis of liquids or solid-liquid interfaces using soft X-ray spectroscopy is presented, which enables the complete sealing of the cell as well as the Transport into vacuum via, for example, a load-lock system. The cell uses pressure monitoring and active as well as passive pressure regulation systems, thereby facilitating the full control over the pressure during filling, sealing, evacuation, and measurement. The cell design and sample preparation as well as the crucial sealing procedure are explained in detail. As a first proof-of-principle experiment, successful nitrogen K-edge fluorescence yield near-edge X-ray absorption fine structure experiments of a biomolecular solution are presented. For this purpose, it is shown that the careful evaluation of all involved parameters, such as window type or photon flux, is desirable for optimizing the experimental result. KW - X-ray spectroscopy KW - Analysis of liquids KW - Wet cell KW - Concanavalin A KW - NEXAFS PY - 2017 U6 - https://doi.org/10.1063/1.5006122 SN - 0034-6748 SN - 1089-7623 VL - 88 IS - 12 SP - 123112-1 EP - 123112-7 PB - American Institute of Physics AN - OPUS4-43611 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streeck, C. A1 - Dietrich, Paul A1 - Fischer, Tobias A1 - Rurack, Knut A1 - Unger, Wolfgang A1 - Beckhoff, B. T1 - Characterization of bio-molecular nano-layers by means of reference-free X-ray Spectrometry N2 - Characterization of bio-molecular nano-layers by means of reference-free X-ray Spectrometry An increasing field of application, e.g. in biotechnology is the dedicated adjustment of surface properties by functionalization with organic molecules. For a detailed understanding and further development of such nano-layers, a quantitative determination of the surface density of molecular species is required. By means of reference-free X-Ray Fluorescence (XRF) spectrometry such surfaces can be analyzed quantitatively by detecting specific marker elements. Using calibrated instrumentation and a quantification approach based on atomic fundamental parameters a SI-traceable quantitative analysis without any calibration sample or reference material is possible. A chemical analysis of molecular bonds can be accomplished by X-Ray Absorption Spectroscopy in the Near-Edge region (NEXAFS). Especially in the soft X-ray range an access to relevant light elements like Carbon C, Nitrogen N and Oxygen is possible. Here, aminated surfaces with varying densities of amino groups prepared from binary mixtures of silanes were investigated. In a complementary analysis by X-Ray Photoelectron Spectroscopy (XPS) and Fluorescence measurements based on laser-excitation in the optical light spectrum the functional-group density of silane monolayers were determined. The nitrogen atom in the head-group of the silane-molecule could be used as specific marker for the reference-free quantitative XRF analysis and were used for traceable calibration of XPS and Fluorescence Spectroscopy. T2 - EMRS Spring Meeting 2017, ALTECH 2017, Symposium S, Analytical techniques for precise characterization of nano materials CY - Strasbourg, France DA - 22.05.2017 KW - XPS KW - XRF KW - Amino silane film KW - Traceability PY - 2017 AN - OPUS4-43374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streeck, C. A1 - Beckhoff, B. A1 - Unger, Wolfgang T1 - Quantitative XRF analysis of industrial thin film samples by calibration using thin film RMs N2 - X-ray fluorescence (XRF) analysis is a well suited methodology for thin film analysis. With XRF the mass deposition of elements can be non-destructively determined. By knowledge of the density of the thin film as well the thickness can be given. In the field of industrial thin film manufacturing various material systems and layer structures are used. the analysis relies on well-known calibration samples or even reference materials to determine absolute analytical results from the measurement values recorded. Within this concept of chemical traceability the calibration sample has to be as similar as possible to the industrial thin film sample with respect to the spatial distribution of elemental composition in order to minimize matrix effects or analysis related uncertainties. The procurement of such certified similar calibration samples or reference materials including their required traceability is a challenge due to limited number of available calibration samples or reference materials, in particular at the nanoscale. There are only few providers of calibration standards for layer or coating thicknesses which are suitable for XRF analysis. The limited number of available certified reference materials (CRMs) for XRF thin film analysis and in parallel the growing market of novel thin film materials induces a growing gap of required calibration samples for XRF analysis. The exploitation of process-near samples benefits from a leverage effect: on one hand reference materials are needed for calibration and alignment procedures for X-ray fluorescence devices. They are customized for the special need of the end-user, e.g. a company producing thin film solar cells. On the other hand the market for EDXRF devices develops positively by providing novel thin film calibration samples for industry and end user-related production processes or application. Two aspects are hereby being addressed; the improvement of product quality which in certain sectors like aerospace and automotive industry directly translates to product safety as well as the expansion of the sales potential of EDXRF measuring devices. T2 - Annual Meeting ISO TC 201 SC10 CY - Brescia, Italy DA - 17.09.2017 KW - XRF KW - Calibration KW - Traceability PY - 2017 AN - OPUS4-43375 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -