@article{EmmerichThielemann2016, author = {Emmerich, Florian and Thielemann, Christiane}, title = {Real-space measurement of potential distribution in PECVD ONO electrets by Kelvin probe force microscopy}, series = {Nanotechnology}, volume = {2016}, journal = {Nanotechnology}, number = {27}, pages = {1 -- 10}, year = {2016}, abstract = {Multilayers of silicon oxide/silicon nitride/silicon oxide (ONO) are known for their good electret properties due to deep energy traps near the material interfaces, facilitating charge storage. However, measurement of the space charge distribution in such multilayers is a challenge for conventional methods if layer thickness dimensions shrink below 1 μm. In this paper, we propose an atomic force microscope based method to determine charge distributions in ONO layers with spatial resolution below 100 nm. By applying Kelvin probe force microscopy (KPFM) on freshly cleaved, corona-charged multilayers, the surface potential is measured directly along the z-axis and across the interfaces. This new method gives insights into charge distribution and charge movement in inorganic electrets with a high spatial resolution.}, subject = {Kelvin-Sonde}, language = {en} } @inproceedings{EmmerichThielemann2011, author = {Emmerich, Florian and Thielemann, Christiane}, title = {Observation of Thermal Discharge in Nanopatterned Electrets by Kelvin-Probe-Microscopy}, series = {14th International Symposium on Elecrets, 2011, Montpellier, France}, booktitle = {14th International Symposium on Elecrets, 2011, Montpellier, France}, isbn = {978-1-4577-1023-0}, issn = {2153-3253}, pages = {149 -- 150}, year = {2011}, subject = {Elektret}, language = {en} } @inproceedings{EmmerichThielemann2014, author = {Emmerich, Florian and Thielemann, Christiane}, title = {Direct Visualisation of Stored Charges in PECVD ONO-Layers by Kelvin-Probe-Force-Microscopy}, series = {15th International Symposium on Electrets ISE}, volume = {2014}, booktitle = {15th International Symposium on Electrets ISE}, address = {Baltimore, USA}, year = {2014}, subject = {Kelvin-Sonde}, language = {en} } @misc{UhrigEmmerich2018, author = {Uhrig, Janis and Emmerich, Florian}, title = {Study on different template-based production processes for magnetic nanowires}, series = {22nd International Student Conference on Electrical Engineering POSTER 2018}, volume = {2018}, journal = {22nd International Student Conference on Electrical Engineering POSTER 2018}, number = {POSTER 2018}, pages = {1 -- 5}, year = {2018}, abstract = {Nickel-iron (NiFe) nanowires with a high contentof nickel and large aspect-ratio show promising characteris-tics for applications in modern micro-systems. In this study,nanowires with well-controlled diameter, height and compo-sition are fabricated using nanoporous poly-carbonate (PC)and anodized aluminum-oxide (AAO) membranes. Differ-ences between potentiostatic and pulsed deposition methodswere studied with regard to their flexibility and a recommen-dation for the best use of the individual types is given. Withthe application of the presented processes, future technolo-gies as magnetic energy-harvesting or nano-fluxgate sensorscan be improved.}, subject = {Nanodraht}, language = {en} } @article{EmmerichThielemann2017, author = {Emmerich, Florian and Thielemann, Christiane}, title = {Optimizing dimensions of unipolar Teflon-FEP piezoelectrets with micro-system-technology}, series = {Journal of Physics: Conference Series}, volume = {2018}, journal = {Journal of Physics: Conference Series}, number = {1052}, pages = {1 -- 4}, year = {2017}, abstract = {In this work we present a new micro-system-technology based production process for unipolar ferroelectrets. Theoretical analysis of the influence of the air-gap size on the electric field distribution as well as on the induced charge on the electrodes shows superior performance of unipolar piezoelectrets with small air-gaps. For the production of these small air-gaps we developed a new design using a photoresist thermoforming master, an integrated micro-heater and shadow masks for metallization. Unipolar piezoelectrets produced with this technology exhibit increased d33-coefficients compared to designs in previous publications. These piezoelectrets are highly preferable for energy-harvesting applications, as they promise high electric power output.}, subject = {Mikrosystemtechnik}, language = {en} } @misc{EmmerichCiba2017, author = {Emmerich, Florian and Ciba, Stefan}, title = {Thin-film Micro-Heater for Fusion Bonding of Teflon-FEP Foils}, series = {21th International Student Conference on Electrical Engineering POSTER 2017}, volume = {2017}, journal = {21th International Student Conference on Electrical Engineering POSTER 2017}, number = {POSTER 2017}, pages = {1 -- 5}, year = {2017}, abstract = {MEMS-based Micro-Heaters, in combination with thin-film temperature sensors, are often used for providing the necessary amount of thermal energy for sensor-applications. In this work, we propose an integrated micro-heater as actuator for fusion bonding of polymers, which can optimize the production process of electret-based micro-energy-harvesters. By adjusting the design parameters of thermoforming-molds, we can implement thin-film micro-heaters that are capable of generating temperatures of above 300°C for numerous cycles. Utilizing the integrated micro-heater allows local fusion bonding of Fluoroethylenepropylene (Teflon-FEP) foils on a micrometer-scale while reducing unnecessary thermal stress. This is beneficial for the longevity of the micro-energy-harvesters, while simultaneously improving its performance.}, subject = {Mikrosystemtechnik}, language = {en} } @inproceedings{EmmerichThielemann2015, author = {Emmerich, Florian and Thielemann, Christiane}, title = {Patterning of PMMA by gold-nanoparticle initiated localized decomposition}, series = {2015 International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO), Changchun, China}, booktitle = {2015 International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO), Changchun, China}, doi = {10.1109/3M-NANO.2015.7425480}, year = {2015}, abstract = {The need for manipulating matter at its smallest scale has been a hot topic in research for the last decades. As the final goal of arranging single atoms has been achieved, research focuses on two targets: firstly, improving the capabilities of existing technologies towards nanometer resolution and secondly, finding new methods for producing nanostructures in a fast and easy way. Here, we present a new maskless method for sub-micro-patterning of poly(methyl methacrylate) (PMMA) thin films. By applying atomic-force-microscope (AFM) assisted nano-xerography, electric charges were locally injected with an AFM-tip into PMMA. The resulting electrostatic patterns attracted charged gold-nanoparticles, which were selectively deposited onto the PMMA layers with lateral dimensions below 200 nm. In a second step, heat treatment at 275 °C initiated a selective decomposition of the PMMA layer, only observed in PMMA-areas covered with nanoparticles, whereas uncovered areas were not modified by the heat treatment. Analyzing the grooves with the AFM, we found that lines with a width in the sub-micrometer range to several micrometers have successfully been realized. We propose this new and promising method to manufacture nano-grooves used as masking for lift-off processes, for functionalization of underlying areas, or for micro-contact-printing.}, subject = {Polymethylmethacrylate}, language = {en} } @inproceedings{NickHockEmmerichetal.2015, author = {Nick, Christoph and Hock, Christina and Emmerich, Florian and Belle, Stefan and Thielemann, Christiane and Asmus, Tim and Loose, Thomas and Wienand, Karlheinz}, title = {Ultrathin gold as sensor platform for biomolecules}, series = {2015 International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO), Changchun, China}, booktitle = {2015 International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO), Changchun, China}, doi = {10.1109/3M-NANO.2015.7425462}, year = {2015}, abstract = {Due to the increasing number of diabetes patients worldwide there is an enormous need for accurate, fast and someday also continuous or even closed loop monitoring of blood glucose level. More than 50 years after Clark and Lyons proposed the first glucose enzyme electrodes this concept is still widely in use today. Most concepts use the enzyme glucose oxidase (GOx) that reacts with glucose. These reactions cause a current that is proportional to the amount of glucose present at the sensor. Thus, if the sample volume is known, the blood sugar level can be measured. Although these electrodes have been in use for so long they have the disadvantage of a limited shelf time. In this work we present an enzyme free approach for glucose detection applying ultrathin gold films. According to the basic Fuchs-Sondheimer-theory and other more sophisticated models the resistivity of ultrathin metal films is dominated by scattering effects at their surface. Chemical reactions at the metallic surface are expected to change the conductivity properties and thus these changes can be used to detect molecules. This can be done by creating a self-assembled monolayer at the gold surface. When molecules such as glucose bind to the end groups of this layer the electron scattering and thus the conductivity of the film is expected to change. Ultrathin gold films with a thickness of 6 nm show the largest relative change in resistivity and are thus the preferred film thickness for this application. These gold films show a significant change in resistance when model molecules sodium sulfide and dextran are present, whereas the resistance of a platinum reference electrode does not change significantly.}, subject = {Biosensor}, language = {en} } @inproceedings{DoehringProbstEmmerichetal.2017, author = {D{\"o}hring, Thorsten and Probst, Anne-Catherine and Emmerich, Florian and Stollenwerk, Manfred and Stehlikova, Veronika and Friedrich, Peter and Damm, Christine}, title = {Development of iridium coated X-ray mirrors for astronomical applications}, series = {Proceedings of the International Society for Optics and Photonics (SPIE)}, volume = {2017}, booktitle = {Proceedings of the International Society for Optics and Photonics (SPIE)}, number = {10399}, publisher = {SPIE}, doi = {10.1117/12.2273988}, pages = {103991C-1 -- 103991C-8}, year = {2017}, abstract = {Future space-based X-ray observatories need to be very lightweight for launcher mass constraints. Therefore they will use a reduced mirror thickness, which results in the additional requirement of low coating stress to avoid deformation of the initial precisely shaped mirror substrates. Due to their excellent reflection properties iridium coatings are sometimes applied for grazing incidence mirrors in astronomical X-ray telescopes. At Aschaffenburg University of Applied Sciences the coating of thin iridium films by an RF-magnetron sputtering technique is under development. The work is embedded in collaborations with the Max-Planck-Institute for Extraterrestrial Physics in Germany, the Czech Technical University in Prague, the Osservatorio Astronomico di Brera in Italy, the German Leibniz Institute for Solid State and Materials Research in Dresden, and the French Institute Fresnel. Sputtering with different parameters leads to iridium films with different properties. The current work is focused on the microstructure of the iridium coatings to study the influence of the substrate and of the argon gas pressure on the thin film growing process. Correlations between coating density, surface micro-roughness, the crystalline structure of the iridium layers, and the expected reflectivity of the X-ray mirror as well as coating stress effects are presented and discussed. The final goal of the project is to integrate the produced prototype mirrors into an X-ray telescope module. On a longer timescale measurements of the mirror modules optical performance are planned at the X-ray test facility PANTER.}, subject = {Iridium}, language = {en} } @inproceedings{DoehringProbstStollenwerketal.2017, author = {D{\"o}hring, Thorsten and Probst, Anne-Catherine and Stollenwerk, Manfred and Emmerich, Florian and Stehl{\´i}kov{\´a}, Veronika and Inneman, Adolf}, title = {Prototyping iridium coated mirrors for X-ray astronomy}, series = {Proceedings of the International Society for Optics and Photonics}, volume = {2017}, booktitle = {Proceedings of the International Society for Optics and Photonics}, number = {10235}, editor = {Hudec, Ren{\´e} and Pina, Ladislav}, publisher = {SPIE International Society for Optics and Photonics}, address = {Bellingham WA}, organization = {Hochschule Aschaffenburg}, doi = {10.1117/12.2265931}, pages = {1023504-1 -- 1023504-8}, year = {2017}, abstract = {X-ray astronomy uses space-based telescopes to overcome the disturbing absorption of the Earth´s atmosphere. The telescope mirrors are operating at grazing incidence angles and are coated with thin metal films of high-Z materials to get sufficient reflectivity for the high-energy radiation to be observed. In addition the optical payload needs to be light-weighted for launcher mass constrains. Within the project JEUMICO, an acronym for "Joint European Mirror Competence", the Aschaffenburg University of Applied Sciences and the Czech Technical University in Prague started a collaboration to develop mirrors for X-ray telescopes. The X-ray telescopes currently developed within this Bavarian- Czech project are of Lobster eye type optical design. Corresponding mirror segments use substrates of flat silicon wafers which are coated with thin iridium films, as this material is promising high reflectivity in the X-ray range of interest. The deposition of the iridium films is based on a magnetron sputtering process. Sputtering with different parameters, especially by variation of the argon gas pressure, leads to iridium films with different properties. In addition to investigations of the uncoated mirror substrates the achieved surface roughness has been studied. Occasional delamination of the iridium films due to high stress levels is prevented by chromium sublayers. Thereby the sputtering parameters are optimized in the context of the expected reflectivity of the coated X-ray mirrors. In near future measurements of the assembled mirror modules optical performances are planned at an X-ray test facility.}, subject = {Iridium}, language = {en} } @article{BuettnerProbstEmmerichetal.2018, author = {B{\"u}ttner, Andre and Probst, Anne-Catherine and Emmerich, Florian and Damm, Christine and Rellinghaus, Bernd and D{\"o}hring, Thorsten and Stollenwerk, Manfred}, title = {Influence of Sputtering Pressure on the Microstructure and Layer Properties of Iridium Thin Films}, series = {Thin Solid Films}, volume = {2018}, journal = {Thin Solid Films}, number = {662}, issn = {0040-6090}, pages = {41 -- 46}, year = {2018}, abstract = {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.}, subject = {Iridium}, language = {en} } @article{ProbstStollenwerkEmmerichetal.2017, author = {Probst, Anne-Catherine and Stollenwerk, Manfred and Emmerich, Florian and B{\"u}ttner, Andre and Zeising, Sebastian and Stadtm{\"u}ller, Johannes and Riethm{\"u}ller, Franziska and Stehlikova, Veronika and Mingwu, Wen and Proserpio, Laura and Damm, Christine and Rellinghaus, Bernd and D{\"o}hring, Thorsten}, title = {Influence of sputtering pressure on the nanostructure and the X-ray reflectivity of iridium coatings}, series = {Surface and Coatings Technology}, volume = {2017}, journal = {Surface and Coatings Technology}, number = {343}, issn = {0257-8972}, pages = {101 -- 107}, year = {2017}, abstract = {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.}, subject = {Iridium}, language = {en} } @article{ProbstBegouDoehringetal.2018, author = {Probst, Anne-Catherine and Begou, Thomas and D{\"o}hring, Thorsten and Zeising, Sebastian and Stollenwerk, Manfred and Stadtm{\"u}ller, Johannes and Emmerich, Florian and Lumeau, Julien}, title = {Coating stress analysis and compensation for iridium-based x-ray mirrors}, series = {Applied Optics}, volume = {2018}, journal = {Applied Optics}, number = {57 (29)}, editor = {Publishing OSA,}, pages = {8775 -- 8779}, year = {2018}, abstract = {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.}, subject = {R{\"o}ntgenteleskop}, language = {en} } @phdthesis{Emmerich2020, author = {Emmerich, Florian}, title = {Eigenschaften und Anwendungen von D{\"u}nnschicht-Elektretmaterialien}, doi = {10.25534/tuprints-00012056}, school = {Technische Hochschule Aschaffenburg}, year = {2020}, subject = {D{\"u}nnschichttechnik}, language = {de} } @article{FlachsEmmerichThielemann2022, author = {Flachs, Dennis and Emmerich, Florian and Thielemann, Christiane}, title = {Fabrication process for FEP piezoelectrets based on photolithographically structured thermoforming templates}, series = {Microsystem Technologies}, volume = {2022}, journal = {Microsystem Technologies}, number = {November}, doi = {doi.org/10.1007/s00542-022-05405-6}, pages = {0 -- 0}, year = {2022}, abstract = {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.}, subject = {Mikrosystemtechnik}, language = {en} } @article{FlachsEmmerichRothetal.2019, author = {Flachs, Dennis and Emmerich, Florian and Roth, Gian-Luca and Hellmann, Ralf and Thielemann, Christiane}, title = {Laser-bonding of FEP/FEP interfaces for a flexiblemanufacturing process of ferroelectrets}, series = {Journal of Physics: Conference Series}, volume = {1407}, journal = {Journal of Physics: Conference Series}, number = {012107}, doi = {10.1088/1742-6596/1407/1/012107}, pages = {1 -- 5}, year = {2019}, abstract = {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.}, subject = {Ultrakurzzeitlaser}, language = {en} }