Filtern
Dokumenttyp
- Posterpräsentation (3) (entfernen)
Sprache
- Englisch (3)
Referierte Publikation
- nein (3)
Schlagworte
- B10 exposure (1)
- Ellipsometric metrology (1)
- Ellipsometry (1)
- FKM polymer (1)
- Polymers (1)
- Reference procedures (1)
- Reference samples (1)
- Standardization (1)
- Themal Transitions (1)
- Thin Films (1)
Organisationseinheit der BAM
- 6 Materialchemie (3) (entfernen)
Ellipsometry is well known as a highly sensitive and reproducible surface analysis technique. However, in a context of metrological applications, the most important property of a measurement process is accuracy, relying on statistical precision, (reproducibility) and trueness (in an absolute sense versus a given standard). The latter is much more difficult to achieve. In this presentation, we discuss the possibility of establishing ellipsometry in a diverse metrological landscape by means of defining standard procedures and best practice methodologies for the measurement and for calibration purposes. The most important task of this approach is to determine the model-inherent uncertainty, originating from parameter coupling. We achieve this by means of sensitivity analysis of the parameters resulting from the fit process. We discuss the definition of reference materials by which accuracy can be made available for ellipsometry, passed along between ellipsometry laboratories and for other measurement techniques. The determination of uncertainty is presented in this work for a number of examples involving difficult analysis models employed for samples from different production environments. We present a standardization initiative with the goal to disseminate this work into an international standard alongside an inter-laboratory study comparing the results for complex samples gained by laboratories with different instrumentation. We also present the results gained within EURAMET projects focused on the metrology of materials with strong non-idealities used in photovoltaics and other energy technology.
Determining thermal transitions in thin polymer layers by means of spectroscopic ellipsometry
(2023)
Thin polymer layers have enormous technical significance as polymer coatings on materials are very cost-effective for tailoring properties of surfaces. Apart from technical aspects in their use, thin polymer layers can be used to determine dimensional aspects in properties of material, such as confinement effects.
In this work, we investigated several different polymer layer materials and determined their glass transition region by means of temperature-dependent spectroscopic ellipsometry. We have optimised our fitting procedure of the ellipsometric data produced in temperature ramp experiments. By this, we could measure the dependence of Tg on the layer thickness in a wide variety of thickness values, proving the existence of confinement effects in the investigated systems. We compare numerical methods for determining the location of the glass transition and discuss the possibilities of different analysis methods when determining thermal transitions. We also discuss the simultaneous existence of these transitions and annealing effects and the implications on the accuracy of the determined data.
Biofuels, particularly biodiesel, have gained significant attention as an alternative to traditional fossil fuels in recent years. Unlike diesel, which contains hundreds of compounds, biodiesel only contains a few compounds in the C16-C18 carbon chain. However, the use of biodiesel in automobile and transportation applications can result in problems of degradation or even damage in materials. Among the commonly used polymer materials, fluorocarbon (FKM) shows excellent performance and high stability and compatibility towards oil, diesel, ethanol, and other chemicals. FKM is a family of fluorocarbon-based fluoroelastomer materials, which provide excellent high-temperature and chemical stability compared to other elastomers. As a result, FKM is widely used in chemical processes such as petroleum refining, where it is used for sealings, pumps, and other components.