TY - JOUR A1 - Büttner, Andre A1 - Probst, Anne-Catherine A1 - Emmerich, Florian A1 - Damm, Christine A1 - Rellinghaus, Bernd A1 - Döhring, Thorsten A1 - Stollenwerk, Manfred T1 - Influence of Sputtering Pressure on the Microstructure and Layer Properties of Iridium Thin Films JF - Thin Solid Films N2 - Iridium layers with low stress, high density, and low surface roughness find widespread use in different high-technology applications. This paper presents a study of the influence of the sputtering pressure on the properties of iridium thin films and of its effect on the substrate surface microstructure. We analysed the dependence of the microstructure, crystalline structure, electrical resistivity, and deposition rate on the sputtering pressure and surface defects of the substrate. For the latter, plasma etching of the substrate was performed for different processing times and its effect on the surface roughness of substrates and, subsequently, on the grown iridium films, was examined. The sputtering pressure and the substrate plasma etching time both had a strong influence on the microstructure and surface roughness. These microstructural changes are in good agreement with the tendency described in the Thornton Structure-Zone Model for different sputtering pressures and the microstructure phase map of Alvarez. The electrical resistivity, deposition rate, and crystalline structure were highly dependent on the sputtering pressure. KW - Iridium KW - microstructure KW - TEM KW - sputtering KW - thin films KW - Iridium KW - Dünne Schicht Y1 - 2018 UR - https://doi.org/10.1016/j.tsf.2018.06.056 SN - 0040-6090 VL - 2018 IS - 662 SP - 41 EP - 46 ER - TY - JOUR A1 - Probst, Anne-Catherine A1 - Stollenwerk, Manfred A1 - Emmerich, Florian A1 - Büttner, Andre A1 - Zeising, Sebastian A1 - Stadtmüller, Johannes A1 - Riethmüller, Franziska A1 - Stehlikova, Veronika A1 - Mingwu, Wen A1 - Proserpio, Laura A1 - Damm, Christine A1 - Rellinghaus, Bernd A1 - Döhring, Thorsten T1 - Influence of sputtering pressure on the nanostructure and the X-ray reflectivity of iridium coatings JF - Surface and Coatings Technology N2 - Reflective mirror coatings made of iridium are used in X-ray telescopes of the Chandra X-ray Observatory (CXO) launched in 1999 by the National Aeronautics and Space Administration (NASA) to investigate astronomical sources at photon energies below 10. keV. These coatings were produced in a DC magnetron sputtering process and have so far proven their suitability for space-based applications. We are considering in the present paper the processing of thin iridium films for lightweight telescopes using the radio frequency magnetron sputtering technique with an oblique angle deposition. The coating development presented here is focused on the influence of total sputtering pressure on film properties as well as on its impact on the mirror's performance. Characterisation methods such as X-ray diffractometry, X-ray reflectometry, atomic force microscopy and transmission electron microscopy have been used. Correlations between morphology, density, surface micro-roughness, crystal structure of the iridium layer and the expected reflectivity of the X-ray mirror are described and discussed. KW - Iridium KW - sputtering KW - microstructure KW - coating KW - X-ray KW - Iridium KW - Röntgenteleskop Y1 - 2017 UR - https://doi.org/10.1016/j.surfcoat.2017.10.062 SN - 0257-8972 VL - 2017 IS - 343 SP - 101 EP - 107 ER - TY - JOUR A1 - Probst, Anne-Catherine A1 - Begou, Thomas A1 - Döhring, Thorsten A1 - Zeising, Sebastian A1 - Stollenwerk, Manfred A1 - Stadtmüller, Johannes A1 - Emmerich, Florian A1 - Lumeau, Julien ED - Publishing OSA, T1 - Coating stress analysis and compensation for iridium-based x-ray mirrors JF - Applied Optics N2 - Iridium-based coatings for mirrors of x-ray telescopes are studied. In particular, stress-induced deformation is characterized and shown to be compressive and equal to −1786  MPa. Two methods for stress compensation are then studied. One relies on the deposition of silica on the back surface of the substrate and a second one relies on the deposition of a chromium sublayer. Advantages and drawbacks of each of these techniques are presented. KW - iridium KW - coating stress KW - X-ray KW - mirror KW - astronomy KW - Röntgenteleskop KW - Iridium KW - Spiegelteleskop Y1 - 2018 UR - https://doi.org/10.1364/AO.57.008775 VL - 2018 IS - 57 (29) SP - 8775 EP - 8779 ER - TY - THES A1 - Emmerich, Florian T1 - Eigenschaften und Anwendungen von Dünnschicht-Elektretmaterialien KW - Dünnschichttechnik KW - Elektret Y1 - 2020 U6 - https://doi.org/10.25534/tuprints-00012056 ER - TY - JOUR A1 - Flachs, Dennis A1 - Emmerich, Florian A1 - Thielemann, Christiane T1 - Fabrication process for FEP piezoelectrets based on photolithographically structured thermoforming templates JF - Microsystem Technologies N2 - Piezoelectrets fabricated from fluoroethylenepropylene (FEP)-foils have shown drastic increase of their piezoelectric properties during the last decade. This led to the development of FEP-based energy harvesters, which are about to evolve into a technology with a power-generation-capacity of milliwatt per square-centimeter at their resonance frequency. Recent studies focus on piezoelectrets with solely negative charges, as they have a better charge stability and a better suitability for implementation in rising technologies, like the internet of things (IOT) or portable electronics. With these developments heading towards applications of piezoelectrets in the near future, there is an urgent need to also address the fabrication process in terms of scalability, reproducibility and miniaturization. In this study, we firstly present a comprehensive review of the literature for a deep insight into the research that has been done in the field of FEP-based piezoelectrets. For the first time, we propose the employment of microsystem-technology and present a process for the fabrication of thermoformed FEP piezoelectrets based on thermoforming SU-8 templates. Following this process, unipolar piezoelectrets were fabri� cated with air void dimensions in the range of 300–1000 lm in width and approx. 90 lm in height. For samples with a void size of 1000 lm, a d33-coefficient up to 26,508 pC/N has been achieved, depending on the applied seismic mass. Finally, the properties as energy harvester were characterized. At the best, an electrical power output of 0.51 mW was achieved for an acceleration of 1 � g with a seismic mass of 101 g. Such piezoelectrets with highly defined dimensions show good energy output in relation to volume, with high potential for widespread applications. KW - Mikrosystemtechnik Y1 - 2022 UR - Microsystem Technologies https://doi.org/10.1007/s00542-022-05405-6 U6 - https://doi.org/doi.org/10.1007/s00542-022-05405-6 VL - 2022 IS - November SP - 0 EP - 0 ER - TY - JOUR A1 - Flachs, Dennis A1 - Emmerich, Florian A1 - Roth, Gian-Luca A1 - Hellmann, Ralf A1 - Thielemann, Christiane T1 - Laser-bonding of FEP/FEP interfaces for a flexiblemanufacturing process of ferroelectrets JF - Journal of Physics: Conference Series N2 - This paper presents an optimized laser-bonding process for piezoelectric energy-harvesters based on thin fluorinated-ethylene-propylene (FEP) foils, using an ultra-short-pulse(USP) laser. Due to the minimized thermal stress in the material during bonding, achieved bypulse durations of few picoseconds, we created seams down to 40μm width without generatingholes in the 12.5μm thick FEP-foils. Using a galvanometer scanning system allowed for fastbonding-speed up to several centimeters per second, making the process also suitable for largestructures and areas. The achieved bond strength of the seams under influence of shearingstress was examined using tensile testing, which showed a sufficient strength of about 25 % of the maximum strength of an unbonded, single layer of FEP. KW - Ultrakurzzeitlaser KW - Piezoelektrizität Y1 - 2019 U6 - https://doi.org/10.1088/1742-6596/1407/1/012107 VL - 1407 IS - 012107 SP - 1 EP - 5 ER -