6.7 Materialsynthese und Design
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Schlagworte
- Spectroscopic ellipsometry (16)
- Haftfestigkeit (8)
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- Centrifugal Adhesion Testing (CAT) (6)
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- IIT (2)
- ISO 14577 (2)
- Instrumented Indentation Testing (2)
- Instrumented indentation testing (2)
- Iridium-titanium mixed oxides (2)
- Kleb- und Haftfestigkeit (2)
- Laser-induced periodic surface structures (LIPSS) (2)
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- Mapping modifizierter Oberflächen (2)
- Mechanical properties (2)
- Mehr-Proben-Prüfung (2)
- Mehrprobenprüfung (2)
- Mesoporous iridium oxides films (2)
- Mesoporous thin films (2)
- Messtechnik (2)
- Messunsicherheit (2)
- Methodology in metrology (2)
- Methodology in testing (2)
- Mikroskaliert (2)
- Modelling (2)
- Müller-Matrix-Ellipsometrie (2)
- NanoSIMS (2)
- Nanoskaliert (2)
- Normung (2)
- Oberflächenanalytik (2)
- Oberflächengeometrie (2)
- Oberflächenmesstechnik (2)
- Particle morphology (2)
- Polymers (2)
- Porous thin films (2)
- Prüftechnik (2)
- Reference procedures (2)
- Selbstkalibrierung (2)
- Silicon (2)
- Stand der Normung (2)
- Structural anomalies (2)
- Structural inhomogenities (2)
- TCO (2)
- 3D coherence scanning interferometry (CSI) (1)
- ALD-Beschichtung (1)
- Abbildende Ellipsometrie (IE) (1)
- Ablation (1)
- Acidic oxygen evolution reaction (1)
- Adhesion (1)
- Adhesive ALD interlayer (1)
- Adhesive strength determination (1)
- Adhesives (1)
- Adhesives - Determination (1)
- Ageing (1)
- Aluminium (1)
- Anwendung von Kohlenstoffschichten (1)
- Atomic layer deposition (1)
- Auger Electron Spectroscopy (1)
- Automated analysis (1)
- Bacterial adhesion (1)
- Bestimmung der Messunsicherheit (1)
- Bimetallic noble metal nanoparticles (1)
- Biofilm (1)
- Biofilm quantification (1)
- Bulk material (1)
- CAT (1)
- CAT – Technology (1)
- CAT-technology (1)
- Centrifugal Adhesion Testing (CAT) Technologie (1)
- Centrifugal Force (1)
- Centrifugal adhesion testing (1)
- Centrifugal adhesion testing (CAT) (1)
- Certified standards (1)
- Coatings (1)
- Complementary methodology and metrology (1)
- Composite strength (1)
- Compound strength (1)
- Compressive Stress (1)
- Corrosion (1)
- Crystallization (1)
- Curved surfaces (1)
- DIN 50989 Parts 1 – 6 (1)
- DIN 50989, Teile 1 bis 6 (1)
- DIN EN 15870 (1)
- DIN EN ISO/IEC 17025 (1)
- DIN EN ISO/IEC 17025:2018 (1)
- DIN EN ISO/IEC 17025:2018 und GUM Kompatibilität (1)
- Data science (1)
- Decorative coatings on polymer substrates (1)
- Deliberate particle implementation (1)
- Depolarization contrast imaging (DCI) (1)
- Dielectric spectroscopy (1)
- Direct laser interference patterning (1)
- Direct laser writing (1)
- Dynamic testing (1)
- Dünne Schichten (1)
- ECD NiFe-layer (1)
- EN 15870 (1)
- Electrochemistry (1)
- Ellipsometric metrology (1)
- Ellipsometric porosimetry (1)
- Ellipsometrie-Norm (1)
- Epoxy (1)
- Fabrication parameters (1)
- Failure pattern (1)
- Faser-Bragg-Gitter (FBG) (1)
- Femtosecond Laser (1)
- Femtosecond laser processing (1)
- Ferrihydrite (1)
- Fiber Bragg grating (FBG) (1)
- Fiber- Bragg-gratings (FBG) (1)
- Functional coatings (1)
- Functionalization (1)
- Gas monitoring (1)
- Gekrümmte Oberflächen (1)
- Glass transition (1)
- Gleitlinien (1)
- Glue (1)
- Heating oil tanks (1)
- Hematite (1)
- Hierarchical structures (1)
- High pressure (1)
- Hybrid metrology measurement (1)
- Hydrogen evolution reaction (1)
- Härte (1)
- Härteverlauf Schweißnaht (1)
- ISO 23131: 2021 (1)
- Imaging ellipsometry(IE) (1)
- Imaging modifizierter Oberflächen (1)
- In situ AFM (1)
- Instrumented Indentation (IIT) (1)
- Instrumented Indentation Testing (IIT) (1)
- Instrumentierte Eindringprüfung (1)
- Instrumentierte Eindringprüfung (IIT) (1)
- Interlaboratory comparision (1)
- Intrinsic OER activity (1)
- Iron oxide (1)
- Kalottenverfahren (1)
- Klassifizierung von Kohlenstoffschichten (1)
- Klebfestigkeit von Stumpfklebungen (1)
- Kompaktierbarkeit (1)
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- Laborvergleich Härte (1)
- Lateral surface pattern (1)
- Layer thickness of transparent coatings (1)
- Loss module (1)
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- Magneto-optical coupling (MOC) (1)
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- Manufacturing (1)
- Material-binding Peptides (1)
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- Mehr-Proben-Prüfverfahren (1)
- Mesoporous films (1)
- Mesoporous iridium-titanium mixed oxides (1)
- Mesoporous mixed metal oxide films (1)
- Messunsicherheit ellipsometrischer Messungen (1)
- Metal coatings (1)
- Metallographie (1)
- Metrology (1)
- Microscopy (1)
- Microstructure (1)
- Mixed Oxides (1)
- Mueller-Matrix Ellipsometry (1)
- Multi-functional coatings for sensors (1)
- Multiple-sample bonding (MSB) (1)
- Multiple-sample handling (MSH) (1)
- Müller-Matrix Ellipsometrie (MM-IE) (1)
- NAP-XPS (1)
- Nano characterization (1)
- Nanoindentation (1)
- Nanoparticle structure (1)
- Niedrigenergie-Polymeren (1)
- Non-destructive ambient analysis (1)
- Normung Ellipsometrie (1)
- Oberflächenprüftechnik (1)
- Optical Constants (1)
- Optical characterization (1)
- Optical fibers (1)
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- Optische Konstanten (1)
- Ordered mesoporous carbon (1)
- Oxidation (1)
- PVD-coatings (1)
- PVD-processes (1)
- PVME (1)
- Particles as add-on features (1)
- Particles as imperfections (1)
- Particulate distributions (1)
- Peptide Library (1)
- Phase transitions (1)
- Physical vapour deposition (PVD) (1)
- Plasma activation (1)
- Plasma diagnostics (1)
- Plasma-assisted ALD modification (1)
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- Plastics (1)
- Platinum-ruthenium colloid (1)
- Polarization spectroscopy (1)
- Polycarbonate (1)
- Polyethylene (1)
- Polymer-binding Peptides (1)
- Polypropylene (1)
- Porosity (1)
- Porous layers (1)
- Porous materials (1)
- Primer (1)
- Prüfgeschwindigkeiten (1)
- Pull-off test (1)
- Quality Control (1)
- Rauheit (1)
- Re-crystallization (1)
- Reactive sputtering (1)
- Reference materials (1)
- Reference samples (1)
- Resins (1)
- Ringversuch (1)
- Ringversuch Ellipsometrie (1)
- Round robin test (1)
- Rroughness and step heights (1)
- SEM/EDS (1)
- SEM/EDS/STRATAGem (1)
- SIMS (1)
- SZ2080 negative photo-resist (1)
- Scanning white light interferometry (1)
- Schichtdicke (1)
- Schichtdicken (1)
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- Service life (1)
- Soft-templated mesoporous films (1)
- Solid-binding Peptides (1)
- Spectroscopic Imaging (1)
- Spectroscopy (1)
- Spektrale Ellipsometrie (SE) (1)
- Standardization of Ellipsometry (1)
- Standardization of ellipsometry (1)
- Statistischen Untersuchung (1)
- Storage module (1)
- Structural Health Monitoring (SHM) (1)
- Structural health monitoring (SHM) (1)
- Structural precision (1)
- Stumpfklebungen (1)
- Surface Activation (1)
- Surface analysis (1)
- Surface analytics (1)
- Surface functionalization (1)
- Surface plasmon resonance enhanced ellipsometry (SPREE) (1)
- Surface texture (1)
- Temperature dependent ellipsometry (1)
- Tensile Stress (1)
- Tensile strength of coatings (1)
- Tensile strength of laminates (1)
- Tensile testing machine (TTM) (1)
- Thin epoxy-based films (1)
- Thin film technology (1)
- Titanium (1)
- Titanium dioxide (1)
- ToF SIMS (1)
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- Validation (1)
- Validation concepts of ellipsometric measurements (1)
- Validierung (1)
- Validierungskonzepte ellipsometrischer Messungen (1)
- Visco-elastic (1)
- Water (1)
- Wear (1)
- Weißlichtinterferenzmikroskopie (WLIM, 3D) (1)
- White Light Interference Microscopy (1)
- White light interference microscopy (1)
- White light interference microscopy(WLIM) (1)
- White light interferometry microscopy (1)
- XRD (1)
- Zirconia: yttria stabilized (1)
- Zugprüfung mittels Zentrifugentechnologie (1)
- Zugprüfung mittels Zugprüfmaschine (1)
- Zweistichproben t Test: (ZPM) (1)
- mechanical properties (1)
- nanoindentation (1)
- performance test (1)
- product specification (1)
- uncertainty (1)
Organisationseinheit der BAM
- 6 Materialchemie (111)
- 6.7 Materialsynthese und Design (111)
- 6.1 Oberflächen- und Dünnschichtanalyse (25)
- 6.2 Material- und Oberflächentechnologien (11)
- 6.6 Physik und chemische Analytik der Polymere (11)
- 8 Zerstörungsfreie Prüfung (6)
- 8.6 Faseroptische Sensorik (6)
- 5 Werkstofftechnik (5)
- 5.1 Mikrostruktur Design und Degradation (4)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (4)
Paper des Monats
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Eingeladener Vortrag
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AbstractTwo‐photon polymerization (2PP) additive manufacturing (AM) utilizes feedstocks of ceramic nanoparticles of a few nanometers in diameter, enabling the fabrication of highly accurate technical ceramic design with structural details as small as 500 nm. The performance of these materials is expected to differ from conventional AM ceramics, as nanoparticles and three‐dimensional printing at high resolution introduce new microstructural aspects. This study applies 2PP‐AM of yttria‐stabilized zirconia to investigate the mechanical response behavior under compressive load, probing the influence of smallest structural units induced by the line packing during the printing process, design of sintered microblocks, and sintering temperature and thereby microstructure. We find a dissipative mechanical response enhanced by sintering at lower temperatures than conventional. The pursued 2PP‐AM approach yields a microstructured material with an increased number of grain boundaries that proposedly play a major role in facilitating energy dissipation within the here printed ceramic material. This microplastic response is further triggered by the filigree structures induced by hollow line packing at the order of the critical defect size of ceramics. Together, these unique aspects made accessible by the 2PP‐AM approach contribute to a heterogeneous nano‐ and microstructure, and hint toward opportunities for tailoring the mechanical response in future ceramic applications.
With the increasing production of renewable energy and concomitant depletion of fossil resources, the demand for efficient water splitting electrocatalysts continues to grow. Iridium (Ir) and iridium oxides (IrOₓ) are currently the most promising candidates for an efficient oxygen evolution reaction (OER) in acidic medium, which remains the bottleneck in water electrolysis. Yet, the extremely high costs for Ir hamper a widespread production of hydrogen (H₂) on an industrial scale. Herein, the authors report a concept for the synthesis of electrode coatings with template-controlled mesoporosity surface-modified with highly active Ir species. The improved utilization of noble metal species relies on the synthesis of soft-templated metal oxide supports and a subsequent shape-conformal deposition of Ir species via atomic layer deposition (ALD) at two different reaction temperatures. The study reveals that a minimum Ir content in the mesoporous titania-based support is mandatory to provide a sufficient electrical bulk conductivity. After ALD, a significantly enhanced OER activity results in dependency of the ALD cycle number and temperature. The most active developed electrocatalyst film achieves an outstanding mass-specific activity of 2622 mA mg(Ir)⁻¹ at 1.60 V(RHE) in a rotating-disc electrode (RDE) setup at 25 °C using 0.5 m H₂SO₄ as a supporting electrolyte.
The performance of functional coatings relies strongly on the stability of the polymer-metal interface. The increasing utilization of multi-material structures in the automotive and aerospace industry necessitates a fundamental understanding of the processes leading to interface degradation for the development of novel strategies to increase corrosion and delamination resistance.
The aim of this project is to investigate the corrosion processes at the buried interface of thin film coated aluminium alloy AA2024-T3 under corrosive and coupled corrosive-mechanical load. A spin coating procedure was developed to synthesize epoxy-like coatings and their nanofiller loaded composites with controlled thickness by layer-by-layer deposition of poly[(o-cresyl glycidyl ether)-co-formaldehyde] and poly-(ethylenimine) bi-layers. Our results indicate that the incorporation of graphene into the epoxy-based coatings leads to the improvement of mechanical and barrier properties. Furthermore, the functional groups play important roles in the interfacial bonding between polymer matrix and the nanofillers. Atomic force microscopy (AFM) results indicate very homogeneous and dense films with a thickness of ~25 nm per bi-layer and the successful integration of the nanofillers into the composite coatings. Ellipsometry measurements of film thickness verified a proportional film growth with the number of deposited layers.
The degradation and delamination behavior of the coating systems was characterized by means of in situ AFM corrosion experiments. Complementary energy dispersive X-ray spectroscopy (EDX) analysis was used to correlate the corrosion and delamination behavior with the different intermetallic particle chemistries and distributions. The presentation will summarize our results on the effect of coating composition and build-up on the local corrosion processes on thin film covered AA2024-T3 aluminium alloys.
The paper addresses the “Functional coatings for mechanical applications: characterization and standardization” and the following points are discussed in more detail:
1. Mechanic alapplications (coatings for tools and components, system features vs. material parameters)
2. Mechanical characterization (instrumented indentation testing (IIT), centrifugal adhesion testing (CAT), state of standardization)
3. Topometric characterization (white light interference microscopy (WLIM, 3D), mechanical stylus (MS, 2D), state of standardization)
4. Optical characterization (spectroscopic ellipsometry (SE), inter-laboratory comparison, state of standardization)
Ellipsometry-based approach for the characterization of mesoporous thin films for H2 technologies
(2021)
Porous thin layer materials are gaining importance in different fields of technology and pose a challenge to the accurate determination of materials properties important for their function. In this work, we demonstrate a hybrid measurement technique using ellipsometry together with other independent methods for validation. Ellipsometry provides information about the porosity of different mesoporous films (PtRuNP/OMC = 45%; IrOx = 46%) as well as about the pore size (pore radius of ca. 5 nm for PtRuNP/OMC). In addition, the electronic structure of a material, such as intraband transitions of a mesoporous IrOx film, can be identified, which can be used to better understand the mechanisms of chemical processes. In addition, we show that ellipsometry can be used as a scalable imaging and visualization method for quality assurance in production. These require accurate and traceable measurements, with reference materials playing an important role that include porosity and other related properties. We show that our novel analytical methods are useful for improving analytical work in this entire field.
Der DIN Ringversuch weist nach, dass die CAT Technologie zur ZPM Prüfung statistisch nicht unterscheidbare Prüfergebnisse liefert, so dass lediglich eine Ergänzung der DIN EN 15870 unter Berücksichtigung der CAT-Technologie (mit Bezug auf äquivalente Kraft und Weg zunahmen) als zweiter normativer Prüfmethode sinnvoll erscheint.
Vorstellung des Revisionsvorschlages im CEN TC 193 am 08.04.2021 mit dem Beschluss, eine Umfrage unter Verwendung des unveränderten deutschen Revisionsvorschlages durchzuführen.
The round robin test proves that the CAT-Technology provides statistically indistinguishable test results compared to TTM. A supplement to DIN EN 15870 taking into account CAT-Technology (with reference to equivalent increases of load and displacement) as second normative test method appears to make sense.
A presentation of a revision proposal at CEN TC 193 has been introduced with the decision to conduct a survey using the unchanged German revision proposal.
Hydrogen production via water electrolysis will be an essential cornerstone in development of sustainable, fossil-free fuel and chemical production on a global scale. The activity and stability of each catalyst is highly dependent on the properties of the coating, i.e., phase composition, crystallinity, accessible surface area, and many other factors. The key to developing improved catalysts is a better understanding of the relationships between their performance, stability, and physicochemical properties. However, these relationships can be complex and are also strongly influenced by the reaction environment. Therefore, operando analysis of the catalyst material during catalysis at realistic potentials and current densities is highly desirable. However, many analytical techniques cannot be applied in liquid environments at realistic potentials and current densities.
We propose environmental ellipsometric analysis in a dedicated electrochemical flow cell as a method to evaluate gas evolution reactions operando under realistic working conditions. Figure 1 illustrates schematically the developed technique. Key factors to success are highly active model-type catalysts, a suitable sample environment, and a deep understanding of the appropriate model development, as well as concise cross validation with numerous other analytical techniques.
The method was developed and validated by analyzing a calcination series (300 – 600 °C) of mesoporous templated IrOx films ex-situ and operando under oxygen evolution reaction (OER) conditions. The employed environmental electrochemical spectroscopic ellipsometric (ECSE) analysis revealed during OER the change of optical and electronic properties, i.e. the dielectric functions, resistivity and band-to-band transitions (p-d band transitions). Film thickness and porosity were validated by means of scanning electron microscopy (SEM), X-ray reflectometry (XRR) or ellipsometric porosimetry (EP), electrical and electronic properties by means of conductivity measurements, X-ray photoelectron spectroscopy (XPS) or UV-Vis-NIR absorption spectroscopy. The electronic structures of the catalysts from valence electron energy loss spectra (VEELS) derived from ε1 and ε2 from SE measurements reveal a direct correlation with electrochemical activities in OER.
In the presentation reversible and irreversible potential-dependent changes of the catalyst properties during operation will be discussed along with the dynamics of gas formation, transport and dissolution at different potentials.
Deep understanding of the effects associated with fabrication parameters and their influence on the resulting structures shape is essential for the further development of direct laser writing (DLW). In particular, it is critical for development of reference materials, where structure parameters are precisely fabricated and should be reproduced with use of DLW technology. In this study we investigated the effect of various fabrication and preparation parameters on the structural precision of interest for reference materials. A well-studied photo-curable system, SZ2080 negative photo-resist with 1 wt.% Michler's ketone (Bis) photo-initiator, was investigated in this work. The correlation between applied laser power, laser velocity, fabrication direction on the deviations in the structure shape were observed by means of white light interferometry microscopy. Moreover, influence of slicing and hatching distances as well as prebake time were studied as function of sample shape. Deviations in the structure form between the theoretically expected and the one detected after DLW fabrication were observed in the range up to 15%. The observed shape discrepancies show the essential importance of fine-tuning the fabrication parameter for reference structure production.
Oberflächenmodifizierte Grundwerkstoffe, insbesondere solche mit funktionellen Schichten, sind in unterschiedlichsten Branchen und Anwendungen anzutreffen. Es werden Quer- und Kalottenschliffe von Einfach- und Mehrschichtsystemen mit Beispielen aus dem Bereich des Korrosions- und Verschleißschutzes sowie dekorativer Anwendungen auf unterschiedlichsten Grundwerkstoffen (X5CrNi1810 Stahl, 100Cr6 Stahl, Hartmetall, ABS und Pappe) vorgestellt. Ebenso vielfältig wie die Grundwerkstoffe sind die Oberflächenmodifizierungen mit Funktionsschichten auf Basis von Nitrierungen, Hartstoffen, diamantähnlichem Kohlenstoff, Metallisierungen und Lackschichten mit Interferenzpigmenten. Neben der Identifikation von Schichtdefekten gilt das Hauptaugenmerk der materialographischen Analyse der Erfüllung der Schichtdickenspezifikation und der Bewertung der Homogenität der Schichtdicke auch bei kritischen Geometrien. Zur Validierung der Schichtdicken- bzw. Längenbestimmung im Querschliff wurde ein Laborvergleichsversuch mit einem Nickel-beschichteten Kupferdraht durchgeführt, den alle der 10 Teilnehmer bestanden.
Eine Grundanforderung an Bauteile ist deren mechanische Integrität, die als Festigkeit (globale Bauteilbeanspruchung) bzw. Tragfestigkeit (lokale Beanspruchung) zu verstehen ist. Die Bauteilfestigkeit wird wesentlich durch das Materialgefüge bestimmt und kann über die Prüfung der Härte des Grundwerkstoffes lokal erfasst werden. Bei Bauteilverbindungen (z.B. Schweißnähte) ist zudem der Übergangsbereich zwischen den Fügeteilen von besonderem Interesse, bei Passungen oder Gleitlagern sind zudem geringe Rauheiten erforderlich, die oft durch mechanische Oberflächen-bearbeitung realisiert werden. Leichtbauweisen können sowohl über hochfeste Stahllegierungen bei geringem Materialeinsatz als auch über Aluminiumlegierungen realisiert werden. Für unterschied-liche Grundwerkstoffe (X2CrNiMo18-14-3, Co-Cr-W-Ni, AlSi10Mg, X5CrNi1810, ferritische Schweiß-nähte) werden an Quer- und Oberflächenschliffen Änderungen im Gefüge, morphologische Besonderheiten, Härteverläufe sowie Änderungen in den Rauheitskennwerten betrachtet, wie sie im Ergebnis mechanischer Oberflächenbearbeitung, bedingt durch den Herstellungsprozess, die Beanspruchung oder den Fügeprozess auftreten. Zur Validierung der Härtebestimmung wurde ein Laborvergleichsversuch an einer MPA-zertifizierten Härtevergleichsplatte und einer 100Cr6 Referenzprobe durchgeführt, den drei bzw. fünf der insgesamt fünf Teilnehmer bestanden.
In recent years, the fabrication of laser-generated surface structures on metals such as titanium surfaces have gained remarkable interests, being technologically relevant for applications in optics, medicine, fluid transport, tribology, and wetting of surfaces.
The morphology of these structures, and so their chemistry, is influenced by the different laser processing parameters such as the laser fluence, wavelength, pulse repetition rate, laser light polarization type and direction, angle of incidence, and the effective number of laser pulses per beam spot area.
However, the characterization of the different surface structures can be difficult because of constraints regarding the analytical information from both depth and the topographic artifacts which may limit the lateral and depth resolution of elemental distributions as well as their proper quantification. A promising technique to investigate these structures even at the nano-scale is Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), a very surface sensitive technique that at the same time allows to perform depth-profiling, imaging and 3D-reconstruction of selected ion-sputter fragment distributions on the surface.
In this study we combine chemical analyses such as Energy Dispersive X-ray spectroscopy (EDX) and high-resolution scanning electron microscopy (SEM) analyses with ToF-SIMS to fully characterize the evolution of various types of laser-generated micro- and nanostructures formed on Ti and Ti alloys at different laser fluence levels, effective number of pulses and at different pulse repetition rates (1 – 400 kHz), following irradiation by near-infrared ultrashort laser pulses (925 fs, 1030 nm) in air environment or under argon gas flow.
We show how this combined surface analytical approach allows to evaluate alteration in the surface chemistry of the laser-generated surface structures depending on the laser processing parameters and the ambient environment.
Crystalline Silicon undergoes a complex phase-change dynamic of melting, amorphization, ablation and re-crystallization upon irradiation with high intensity ultra-short laser pulses [1]. The final state of such a modified surface spot depends on many factors, most notably the local fluence and the surface’s crystal orientation. In this study, we induced superficial structure and phase changes in Silicon <111> and <100> wafers using single femtosecond laser pulses (790 nm, 30 fs) for a range of different peak fluences. The resulting surface modifications were studied in great detail using a number of different techniques, including spectroscopic imaging ellipsometry (SIE), atomic force microscopy, high-resolution transmission electron microscopy (HRTEM), and energy dispersive X-ray spectroscopy within scanning transmission electron microscopy (STEM-EDX).
Playing a pivotal role in this work, SIE provided non-destructive measurements for the calculation of the radial amorphous layer-thickness profiles of the irradiated spots using a two-layer thin-film model (Silicon dioxide and amorphous Silicon on a crystalline Silicon substrate). The measurements further allowed for the analysis of the oxide-layer modifications induced by the laser treatment. The results of the SIE-calculations were cross-checked by an in-depth material lamella via HRTEM and STEM-EDX.
Ellipsometry has been an extremely successful and fast expanding method in the past decades along with other related techniques using polarisation sensitive measurements. Opening new fields of application for a successful measurement technique brings some requirements and issues that have to be solved. From a metrological point of view, ellipsometry has the problem that uncertainties are difficult to determine for model-based analysis techniques in general. In this presentation, we will explore how the usefulness of polarimetric methods like ellipsometry can be increased.
Ellipsometry as a method could profit from several current developments which will be discussed in this presentation:
• Standardisation initiatives on national and international level developing standards for best practice when using ellipsometry. A series of at least six standards is currently developed on national German and international level covering different levels of sample complexity.
• Projects on traceability of ellipsometry and structured surface spectrometry as well as new dielectric function database initiatives.
• Metadata handling and data ontology providing a better framework for exchange and collaborative use of research data.
We will also explore the quantification of measurement uncertainty using examples from projects in which BAM is involved. Examples will be presented of multilayer and non-ideal materials as well as the determination of layer properties for technical applications such as thin layer catalysts and complex polymers. The definition of reference materials will be discussed.
Ellipsometry is a powerful tool, which allows the investigation of material properties over a broad spectral range. Over the course of several years, the ellipsometry lab at BAM has become an accredited testing lab according to ISO/IEC 17025 laying bare the need of better methods for accuracy and traceability. Despite its wide range of application in both research and development as well as industry, there have been no generally accepted standards dealing with model validation and measurement uncertainties.
Based on the first German standard DIN 50989 – 1: 2018 Ellipsometry - Part 1: Principles (currently international standard ISO 23131: 2021) and under consideration of GUM [1] a series of standards for ellipsometry was developed. The entire 6-part series covers several model-based application cases. This standards series avoids having narrow and material specific application cases but instead classifies applications of ellipsometry according to the sample complexity. The concept of ellipsometric transfer quantities (Ψ and Δ or alternatively the elements of transfer matrices) is implemented in the series. For each application case a model-based validation strategy was developed. Thus, the standards are applicable to all materials, instruments and measuring principles.
The uniform structure concept of the series facilitates its practical applicability for users. The standards include the model-based GUM-compliant determination/estimation of the measurement uncertainties. In addition, the appendices of the documents contain numerous measurement and simulation examples as well as recommendations for measuring practice.
In this contribution we present the application cases and basic structure of the standards developed in collaboration with Accurion GmbH and SENTECH Instruments GmbH in the project SNELLIUS.
Silicon is the material responsible for most of the technological developments during the past century, making it one of the most studied materials along different disciplines. However, there are still unturned stones regarding its superficial re-solidification after femtosecond laser-induced local melting. In this presentation, we report irradiation experiments with single femtosecond pulses (790 nm, 30 fs) with a spatially Gaussian distribution on two different types of silicon with orientations <111> and <100>. The surface modifications were studied in detail via different techniques, including optical microscopy, atomic force microscopy, spectroscopic imaging ellipsometry, energy dispersive X-ray spectroscopy and high-resolution transmission electron microscopy. We quantitatively estimate the resulting radial amorphous layer depth profiles with maximum thicknesses around some tenths of nanometers for fluences in between the melting and ablation thresholds. In particular, spectroscopic imaging ellipsometry (SIE) allowed fast data acquisition using multiple wavelengths to provide experimental measurements for calculating the nanometric radial amorphous layer thickness profiles with micrometric lateral resolution based on a thin-film layer model. SIE proved to be capable of detecting and measuring nanometric structural and chemical modifications (oxidation) on the studied laser spots. The accuracy of the SIE-based calculations is verified experimentally by characterizing an in-depth material lamella via high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (STEM-EDX). For completeness, we present a mathematical modelling for the melt layer thickness considering different optical absorption processes including one photon absorption, two photon absorption and free-carrier absorption, highlighting the relevance of the latter one in the femtosecond laser-induced melting of silicon.
Rising energy demand and the impending climate change require the development of a sustainable, fossil-free fuel and chemical production on a global scale. Hydrogen production via water electrolysis will be a fundamental cornerstone in this endeavor. The activity and stability of respective electrode coatings strongly depends on the coating's properties, i.e. phase composition, crystallinity, electrical conductivity, accessible surface, wettability and many other factors. The key to the development of improved catalysts is a better understanding of the relations between their performance, stability and physicochemical properties. However, those relations can be complex, and are strongly influenced also by the reaction environment. Hence, operando analysis of the catalyst material during catalysis at realistic potentials and current densities is highly desirable. Yet, many analytical techniques cannot be applied in liquid environments at realistic potentials and current densities.
We propose environmental ellipsometric analysis in a dedicated electrochemical flow cell as a new method to evaluate gas evolution reactions operando under realistic working conditions. Figure 1 illustrates schematically the developed technique. Key factors to success are highly active model-type catalysts with template-controlled porosity, a suitable sample environment, a deep understanding of the spectroscopic method and respective model development, as well as concise cross validation with numerous other analytical techniques.
The method was developed and validated by analyzing a calcination series (300 - 600°C) of mesoporous templated IrOx films ex-situ and operando under oxygen evolution reaction (OER) conditions. The employed environmental electrochemical spectroscopic ellipsometric analysis (ECSE) revealed during OER the change of optical and electronic properties, i.e. the dielectric functions (real ε1 and imaginary part ε2), electrical and electronic properties such as resistivity (ρ) and band-to-band transitions (p-d band transitions). Film thickness and porosity were validated by means of scanning electron microscopy (SEM), X-ray reflectometry (XRR) or ellipsometric porosimetry (EP), electrical and electronic properties by means of conductivity measurements, X-ray photoelectron spectroscopy (XPS) or UV-Vis-NIR absorption spectroscopy. The electronic structures of the catalysts from valence electron energy loss spectra (VEELS) derived from the real (ε1) and imaginary part (ε2) of the dielectric function from SE measurements reveal a direct correlation with electrochemical activities in OER.
In the presentation reversible and irreversible potential-dependent changes of the catalyst properties during operation will be discussed along with the dynamics of gas formation, transport and dissolution
Rising energy demand and the impending climate change require the development of a sustainable, fossil-free fuel and chemical production on a global scale. Hydrogen production via water electrolysis will be a fundamental cornerstone in this endeavor. The activity and stability of respective electrode coatings strongly depends on the coating's properties, i.e. phase composition, crystallinity, electrical conductivity, accessible surface, wettability and many other factors. The key to the development of improved catalysts is a better understanding of the relations between their performance, stability and physicochemical properties. However, those relations can be complex, and are strongly influenced also by the reaction environment. Hence, operando analysis of the catalyst material during catalysis at realistic potentials and current densities is highly desirable. Yet, many analytical techniques cannot be applied in liquid environments at realistic potentials and current densities.
We propose environmental ellipsometric analysis in a dedicated electrochemical flow cell as a new method to evaluate gas evolution reactions operando under realistic working conditions. Figure 1 illustrates schematically the developed technique. Key factors to success are highly active model-type catalysts with template-controlled porosity, a suitable sample environment, a deep understanding of the spectroscopic method and respective model development, as well as concise cross validation with numerous other analytical techniques.
The method was developed and validated by analyzing a calcination series (300 - 600°C) of mesoporous templated IrOx films ex-situ and operando under oxygen evolution reaction (OER) conditions. The employed environmental electrochemical spectroscopic ellipsometric analysis (ECSE) revealed during OER the change of optical and electronic properties, i.e. the dielectric functions (real ε1 and imaginary part ε2), electrical and electronic properties such as resistivity (ρ) and band-to-band transitions (p-d band transitions). Film thickness and porosity were validated by means of scanning electron microscopy (SEM), X-ray reflectometry (XRR) or ellipsometric porosimetry (EP), electrical and electronic properties by means of conductivity measurements, X-ray photoelectron spectroscopy (XPS) or UV-Vis-NIR absorption spectroscopy. The electronic structures of the catalysts from valence electron energy loss spectra (VEELS) derived from the real (ε1) and imaginary part (ε2) of the dielectric function from SE measurements reveal a direct correlation with electrochemical activities in OER.
In the presentation reversible and irreversible potential-dependent changes of the catalyst properties during operation will be discussed along with the dynamics of gas formation, transport and dissolution at different potentials.