TY - CONF A1 - Unger, Wolfgang A1 - Müller, Anja A1 - Heinrich, Thomas A1 - Kunz, Valentin A1 - Nymark, P. A1 - Radnik, Jörg T1 - Chemical characterization of nanoparticles by PCA-assisted ToF-SIMS: a) Core-shell character, b) transformation and c) grouping studies N2 - This talk was given within the scope of the SIMS-22 conference in October 2019 in Kyoto (Japan). It deals with the surface analytical investigation of nanoparticles by PCS-assisted ToF-SIMS. This technique is applicable to core-shell nanoparticles, in order to distinguish a complete encapsulation from an incomplete encapsulation of the core by the shell material. Furthermore, the depletion process of organic nanoparticle coatings caused by UV-weathering is investigated. Finally, the significance of grouping studies for nanomaterials research and risk assessment is demonstrated. T2 - The 22nd International Conference on Secondary Ion Mass Spectrometry (SIMS-22) CY - Kyoto, Japan DA - 20.10.2019 KW - Nanoparticles KW - ToF-SIMS KW - Principal component analysis (PCA) PY - 2019 AN - OPUS4-50075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Wolfgang T1 - Metrology for spatially resolved chemical analysis at the micro and nanometre scales Surface Analysis Working Group (SAWG) - Report for 17th Meeting (2018/19) N2 - The SAWG was established as an ad-hoc working group in 2003 before being established as a permanent working group. The first comparison was in 2007. Dr Unger recalled the terms of reference for the group, which paralleled those of the CCQM itself, with a focus on spatially resolved chemical surface analysis at the micro- and nano-scale. The group also had a remit to act as a forum for exchange of information on research and development of surface analysis, establish contact with relevant stakeholders and promote the development of SI traceable chemical surface measurements. The group currently had participants from 18 institutes, although five had not sent participants to recent meetings. Reporting progress on studies, Dr Unger said that P-190CCQM-K-157 (measurement of HfO2 in thin film) had been completed, and the subsequent K-157 approved is ongoing and that for CCQM-K153 (Measurement of Specific Adsorption of N2 and Kr on nonporous SiO2 at liquid nitrogen temperature by BET) was at the draft B was completed stageand distributed to CCQM WG chairpersons for approval. Dr Unger reported that CCQM-K-153 had covered measurement of specific absorption of nitrogen or krypton on nonporous silica at liquid nitrogen [ambient] temperature. This included an application of the BET method, a standard method for determination of surface area. This fitted into the ‘nonporous’ region of the SAWG measurement space, which included microporous, mesoporous and microporous regions. Of these regions, CCQM-K136 and CCQM-K153 demonstrated capability in meso- and microporous media respectively. CCQM-K153 involved two measurands; amount of absorbed gas at liquid nitrogen temperature, expressed as specific absorption, and the BET surface area. Specific absorption could in principle be traceable to the SI; BET was operationally defined. Five institutes participated. A detailed uncertainty budget was available for both measurands. Results had been excellent, with all laboratories agreeing well within their uncertainties and all in agreement with the reference value. Reporting on CCQM P190, Dr Unger described the study objective measurand (amount of substance of HfO2 in a thin film), samples and methods. After showing transmission electron microscope images obtained in the study, he briefly reviewed the conclusions. The study identified a need to handle carbon contamination, harmonise the XPS measurement protocol, determine emission angle and identify a consensus value for attenuation length. These conclusions had informed the design of the proposed ongoing K157 study approved at the 24th Meeting of te CCQM. The group planned a number of comparisons for the next three years: 2019: A pilot study on the amount of substance in a thin organic layer (previously approved). 2020: CCQMK-157, Measurement of the amount of substance of HfO2; A Key comparison on specific gas adsorption on microporous samples and a Pilot study on Homogeneous surface composition of an ionic liquid. 2021: A key comparison measuring the amount of substance in a thin organic layer. Dr Unger additionally described a recently proposed pilot study to examine chemical composition in a deep nanoscale layer. This was important for the electronics industry. Four participants had expressed interest. The measurand will be the amount of Ir(ppy)2(acac) in a thin organic layer within an organic layer stack on a silicon substrate. He also reported that SAWG had started work on characterisation of graphene material grown by chemical vapour decomposition (CVD). The work would examine coverage on the substrate, number of layers, level of disorder, uncertainty budgets associated with the measurement, and data analysis. A link to VAMAS Technical Work Area 41 “Graphene and Related 2D Materials“ would also be established. Looking forward, Dr Unger said the group had established a task group on application of Raman spectroscopy. This had important applications but was currently seen as qualitative. He presented the terms of reference for the task group for approval by the CCQM. Dr Unger reviewed the SAWG activities that have progressed the state of the art in measurement science. He listed the past and ongoing comparisons that had addressed new and challenging measurement problems, and drew attention to a number of key publications in surface analysis. He additionally described stakeholder engagement activities, including collaboration with VAMAS, input to ISO TC 201, contributions to Euramet projects, and contributions to two recent stakeholder workshops. T2 - 25th meeting of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM) CY - Paris, France DA - 11.04.2019 KW - Surface chemical analysis KW - Metrology KW - International Meter Convention PY - 2019 AN - OPUS4-48020 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Wolfgang T1 - Metrology for spatially resolved chemical analysis at the micro and nanometre scales Surface Analysis Working Group (SAWG) - Report for 16th Meeting (2017/18) N2 - Following the 2017 meeting, progress with the Key Comparison CCQM-K153 related to the BET specific surface lead by UNIIM and the Pilot Study P-190 “Thickness Measurement of nm HfO2 Films” lead by KRISS will be discussed. The 16th meeting of SAWG will focus on •survey on CMC claims submitted with reference to K-129 and K-136. •the overall and SAWG specific aspects of the CCQM Strategy process, •a consideration of comparisons on convention methods as recommended by the CCQM Plenary Meeting 2017, •the 2019 CCQM Workshop and paper(s) for Metrologia’s Special Issue, •discussion of future comparisons. T2 - 24th meeting of the CCQM 2018 CY - Paris, France DA - 19.04.2018 KW - Surface chemical analysis KW - Metrology KW - Inter-laboratory comparisons PY - 2018 AN - OPUS4-44998 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kjaervik, Marit A1 - Unger, Wolfgang T1 - New work item proposal for a technical report for ISO/TC 201 WG4 “Surface characterization of biomaterials”: Surface chemical analysis – Surface chemical analysis of cells and biofilms N2 - The proposed ISO Technical Report provides a description of a variety of physical methods of analytical chemistry by which bacteria and biofilms can be analysed. The state of the art, sample requirements and strengths associated with each method are identified. Presented at the DIN-meeting for NA 062-08-16 AA „Chemische Oberflächenanalyse und Rastersondenmikroskopie“ T2 - 18. Sitzung des DIN-meeting NA 062-08-16 AA "Chemische Oberflächenanalyse und Rastersondenmikroskopie“ CY - Berlin, Germany DA - 08.11.2018 KW - 3D nano SIMS KW - Fourier transform infrared spectroscopy KW - Raman-spectroscopy KW - Biofilms KW - XPS PY - 2018 AN - OPUS4-46548 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Wolfgang A1 - Ehlert, Christopher A1 - Donskyi, Ievgen A1 - Girard-Lauriault, P.-L. A1 - Lippitz, Andreas A1 - Illgen, Rene A1 - Haag, R. A1 - Adeli, M. T1 - Chemical modification of graphene and carbon nano tubes as viewed by xps and nexafs spectroscopies with dft spectra simulation N2 - Graphene is a two-dimensional carbon network with unique properties. However, its low solubility, poor reactivity and the limited accessibility of a well-defined basal plane are major challenges for applications. An ideal method to overcome these problems is the covalent attachment of functional molecules to its surface which enable further reactive modifications for specific applications. There are several technologies for surface functionalization of graphene and related CNT materials. To get control on the functionalization process and to optimize the performance of the modified surfaces analytical tools for surface chemical characterization are required. X-ray absorption (NEXAFS) and photoelectron spectroscopy (XPS) have been identified to be rather powerful here [1-3]. Specifically, NEXAFS spectroscopy underpinned by quantum chemical spectrum simulations [4] is unique in a way to address changes of aromaticity and defect formation at the graphene surface during functionalization. For relevant surface modification technologies, we present examples on how NEXAFS and XPS can do a good job. All presented modifications aim on the production of platforms for defined functional 2D nanomaterials, as for example multifunctional hybrid architectures. In detail, we investigated: • A wet chemical method for covalent functionalization of graphene sheets by a one-pot nitrene [2+1] cycloaddition reaction under mild conditions. Here a reaction between 2,4,6-trichloro-1,3,5-triazine and sodium azide with thermally reduced graphene oxide (TRGO) results in defined dichlorotriazine-functionalized graphene sheets. • Graphene and carbon nanotube functionalized by Vacuum-Ultraviolet (VUV) induced photochemical or r.f. cw low pressure plasma processes to introduce amino, hydroxy or brominated functionalities. To underpin finger-print information delivered by C K-edge NEXAFS we studied the effects of selected point and line defects as well as chemical modifications for a single graphene layer model by density functional theory based spectrum simulations. References [1] P.-L. Girard-Lauriault et al., Appl. Surf. Sci., 258 2012 8448-8454, DOI: 10.1016/j.apsusc.2012.03.012 [2] A. Lippitz et al., Surf. Sci., 611 2013 L1-L7, DOI: 10.1016/j.susc.2013.01.020 [3] A. Faghani et al., Angew. Chemie (International ed.), 56 2017 2675-2679, DOI:10.1002/anie.201612422 [4] C. Ehlert, et al., Phys.Chem.Chem.Phys., 16 2014 14083-14095, DOI: 10.1039/c4cp01106f T2 - AVS 65th INTERNATIONAL SYMPOSIUM CY - Long Beach, CA, USA DA - 21.10.2018 KW - Graphene KW - Plasma KW - Nitrene [2+1] cycloaddition KW - XPS KW - NEXAFS PY - 2018 AN - OPUS4-46468 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Wolfgang T1 - Acquiring and Documenting Reproducible Spectra, Depth Profiles and Images: XPS, AES and SIMS N2 - In this talk sample prep/handling, instrument calibration and data acquisition methods with examples from XPS, Auger and SIMS will be addressed in terms of their contributions to the reproducibility of data delivered by the methods. Active parties in the field are VAMAS TWA 2 “Surface chemical analysis” (http://www.vamas.org/twa2/index.html), ISO/TC 201 “Surface chemical analysis” (https://www.iso.org/committee/54618.html) and the Surface Analysis Working Group (SAWG) at the International Meter Convention (https://www.bipm.org/en/ committees/cc/wg/sawg.html). The tools to improve the reproducibility of spectra, depth profiles and images at these international platforms are inter-laboratory comparisons, validated SOPs, standards and certified reference materials (CRM) as well as uncertainty budgets and establishment of traceability chains. The last point is of specific importance because all the methods, XPS, Auger and SIMS, are not primary methods. To address quantitative XPS, AES and SIMS results of relevant inter-laboratory comparisons organized by SAWG considering measurands as alloy surface composition and thickness of thin films will be introduced. These comparisons delivered results which are viewed to be benchmarking, some of them resulted in ISO/TC 201 standards. For quantitative XPS and AES the principal outline of an uncertainty budget will be discussed together with the audience. Another issue of quantitative XPS which definitely needs consideration are valid methods for a determination of the transmission function of the instruments and even for the emission angle in the respective experiments. Concerning the field of depth profiling it has to be investigated together with the audience whether the ISO (or ASTM) standards we have are sufficient to guarantee comparable results. Having in mind the number of different sputter ion species available today and range of samples of interest (metals, semiconductors, organic films) this might be questionable. And, how do depth profiling by AR-XPS and variable excitation energy XPS compete here? For imaging surface chemical analysis, the characterization of the imaging system is an issue to be investigated. Here the determination of lateral resolution is a relevant topic. Finally, the future needs to develop metrology for new applications e.g., ambient-pressure XPS, bio samples, and core-shell nanoparticles, will be issues raised for a discussion with the audience. T2 - 17th Topical Conference on Quantitative Surface Analysis (QSA 17) CY - Long Beach, CA, USA DA - 21.10.2018 KW - Depth Profiles and Images KW - X-ray Photoelectron Spectroscopy (XPS) KW - Auger Electron Spectroscopy (AES) KW - SIMS KW - Reproducible Spectra PY - 2018 AN - OPUS4-46470 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Wolfgang A1 - Kjaervik, Marit T1 - New work item proposal for a technical report for ISO/TC 201 WG 4 “Surface characterization of biomaterials”: Surface chemical analysis – Surface chemical analysis of cells and biofilms N2 - The proposed ISO Technical Report provides a description of a variety of physical methods of analytical chemistry by which bacteria and biofilms can be analysed. The state of the art, sample requirements and strengths associated with each method are identified. T2 - 27th Plenary Meeting of ISO/TC 201 CY - Cancun, Mexico DA - 2018-09-20 KW - Surface chemical analysis of biofilms KW - XPS KW - Fourier-Transform Infrared Spectroscopy KW - 3D nano SIMS KW - Raman-spectroscopy PY - 2018 AN - OPUS4-46214 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Wolfgang A1 - Sobol, Oded A1 - Straub, Franka A1 - Nolze, Gert A1 - Wirth, Thomas A1 - Böllinghaus, Thomas T1 - Tof-SIMS imaging of Deuterium in DSS steel microstructures and data fusion with SEM topography data: Towards a better understanding of hydrogen assisted cracking in steel N2 - The use of duplex stainless steels (DSS) in energy related applications is well known. Nowadays, DSS steels become more favorable than austenitic steels due to the outstanding mechanical properties, the good corrosion resistance and the lower nickel content. However, the use of the duplex grade in acidic environments such as seawater often leads to severe degradation of the structural integrity of the steel by hydrogen-induced/assisted cracking (HAC) phenomena, which can eventually result in premature failure. Hydrogen assisted degradation and cracking of steels are active fields of research even though this topic is intensively studied for more than a century. A bottleneck is the analytical validation of the theoretical models proposed ion the literature at the sub-micron scale. Industrial and the research communities see a need for an accurate analytical method by which it is possible to image the distribution of hydrogen in the microstructure of a steels or and other alloys. Among the very few available methods hydrogen imaging methods, Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) has the principal capability for mapping of hydrogen in a steel’s microstructure. The combination of ToF-SIMS with multivariate data analysis (MVA), electron microscopy (SEM) and electron-backscattered diffraction (EBSD) is a powerful approach for providing chemical and structural information. The use of data fusion techniques has been shown recently to enhance the better understanding of the hydrogen induced degradation processes in in a DSS steel. T2 - The Scientific International Symposium on SIMS and Related Techniques Based on Ion-Solid Interactions (SISS19) CY - Kyoto, Japan DA - 11.5.17 KW - Hydrogen KW - DSS steel KW - ToF SIMS KW - SEM KW - EDX KW - EBSD KW - Data fusion PY - 2017 AN - OPUS4-40276 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Wolfgang T1 - Metrology for spatially resolved chemical analysis at the micro and nanometre scales - Surface analysis working group (SAWG) - Report for 15th meeting (2016/17) N2 - CCQM has established a framework of comparisons to demonstrate the international comparability of chemical measurements. The key point is the establishment of comparable measurements, with traceability to internationally or nationally stated references. Originally initiated by Dr Martin P Seah, NPL, the Surface Analysis Working Group (SAWG) has been formally founded in 2003. The following terms of reference were presented to CCQM in April 2002. CCQM ratified the group as a full working group of CCQM in April 2003 with these terms of reference: - to develop pilot studies and carry out key comparisons of national measurement standards for surface and micro/nano-analysis; - to assist in identifying and establishing inter-laboratory work to improve the traceability of surface and micro/nano-analysis; - to establish and update a work plan to be adopted by CCQM; - to discuss and review the scope of the working group and to liase with other working groups related to nanotechnology. Following the 2016 meeting, the Key Comparison K-129 "Measurement of atomic fractions in Cu(In,Ga)Se2 Films" lead by KRISS and the Key Comparison K-136 on "BET specific surface area of nanoporous Al2O3" lead by UNIIM&BAM have been finished in 2016. The 15th meeting of SAWG will focus on - survey on CMC claim submitted with reference to K-129 and K-136. - the overall and SAWG specific aspects of the CCQM Strategy process, - a joint meeting with the Inorganic Working Group addressing number concentrations of nano particles, - discussion of future comparisons. T2 - CCQM Plenary Meeting at BIPM 2017 CY - Paris, France DA - 27.4.17 KW - Metrology KW - Comparisons KW - CCQM PY - 2017 AN - OPUS4-40277 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Wolfgang A1 - Lippitz, A. A1 - Illgen, R. A1 - Ehlert, C. A1 - Girard-Lauriault, P.-L. A1 - Donskyi, Ievgen A1 - Haag, R. A1 - Adeli, M. T1 - Low pressure plasma, UV photo and wet chemical modification of graphite, graphene and carbon nano tubes N2 - Graphene is a two-dimensional carbon network with unique properties, including high mechanical stiffness, strength, and elasticity, outstanding electrical and thermal conductivity, and many others. Despite these advantages, its low solubility, poor reactivity and the limited accessibility of a well-defined basal plane are major challenges for applications. An ideal method to overcome these problems is the covalent attachment of functional molecules to its surface which enables further reactive modifications for specific applications. There is a number of different technologies for surface functionalization of graphene and related CNT materials. However, to get control on the functionalization process and to optimize the performance of the modified surfaces analytical tools for surface chemical characterization are required. X-ray absorption (NEXAFS) and photoelectron spectroscopy (XPS) have been identified to be rather powerful here. Specifically NEXAFS spectroscopy underpinned by quantum chemical spectrum simulations is unique in a way to address changes of aromaticity and defect formation at the graphene surface during functionalization. For relevant surface modification technologies, we present examples on how NEXAFS and XPS can perform well. All presented modifications aim on the production of platforms for defined functional 2D nanomaterials, as for example multifunctional hybrid architectures. In detail, we investigated: • Graphene and carbon nanotube functionalized by a Vacuum-Ultraviolet (VUV) induced photochemical process in NH3 or O2 atmospheres in order to introduce amino or hydroxy functionalities, respectively. • Br bonding on r.f. cw low pressure plasma brominated graphite surfaces by using Br2 and bromoform as plasma gases. • A wet chemical method for covalent functionalization of graphene sheets by a one-pot nitrene [2+1] cycloaddition reaction under mild conditions. Here a reaction between 2,4,6-trichloro-1,3,5-triazine and sodium azide with thermally reduced graphene oxide (TRGO) results in defined dichlorotriazine-functionalized graphene sheets. T2 - The 17th European Conference on Applications of Surface and Interface Analysis CY - Montpellier, France DA - 24.09.2017 KW - Graphene KW - XPS KW - NEXAFS PY - 2017 AN - OPUS4-42787 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -