@misc{HayatRatzkeAlvaradoChavarinetal., author = {Hayat, Ahsan and Ratzke, Markus and Alvarado Chavarin, Carlos and Z{\"o}llner, Marvin Hartwig and Corley-Wiciak, Agnieszka Anna and Schubert, Markus Andreas and Wenger, Christian and Fischer, Inga Anita}, title = {Structural and morphological properties of CeO2 films deposited by radio frequency magnetron sputtering for back-end-of-line integration}, series = {Thin Solid Films}, volume = {807}, journal = {Thin Solid Films}, issn = {0040-6090}, doi = {10.1016/j.tsf.2024.140547}, pages = {3}, language = {en} } @misc{HayatSpiritoCorleyWiciaketal., author = {Hayat, Ahsan and Spirito, Davide and Corley-Wiciak, Agnieszka Anna and Schubert, Markus Andreas and Masood, Maria and Reichmann, Felix and Ratzke, Markus and Capellini, Giovanni and Fischer, Inga Anita}, title = {MBE-based growth of Sn-rich quantum wells and dots at low Sn deposition rates}, series = {Materials Science in Semiconductor Processing}, volume = {165}, journal = {Materials Science in Semiconductor Processing}, issn = {1873-4081}, doi = {10.1016/j.mssp.2023.107693}, language = {en} } @misc{KalraAlvaradoChavarinNitschetal., author = {Kalra, Amanpreet and Alvarado Chavarin, Carlos and Nitsch, Paul-Gregor and Tschammer, Rudi and Flege, Jan Ingo and Ratzke, Markus and Zoellner, Marvin Hartwig and Schubert, Markus Andreas and Wenger, Christian and Fischer, Inga Anita}, title = {Deposition of CeOₓ/SnOₓ-based thin films via RF magnetron sputtering for resistive gas sensing applications}, series = {Physica B, Condensed matter}, volume = {723}, journal = {Physica B, Condensed matter}, publisher = {Elsevier BV}, address = {Amsterdam}, issn = {0921-4526}, doi = {10.1016/j.physb.2025.418098}, pages = {1 -- 7}, abstract = {Cerium oxide-tin oxide (CeOx/SnOx) thin films with varying Sn content were deposited using RF magnetron sputtering and investigated for hydrogen sensing applications. Structural, compositional, and morphological properties were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). Gas sensing measurements showed effective hydrogen detection at room temperature, with the sensitivity strongly influenced by Sn content and oxygen vacancy concentration. Higher Sn concentration enhanced the sensing response, which was correlated with microstructural features obtained from AFM and EDX, as well as with the presence of Ce3+ and Ce4+ oxidation states identified by XPS. This study highlights the potential of CeOx/SnOx thin films for possible back-end-of-line integration and provides proof-of-principle for room-temperature hydrogen sensing.}, language = {en} } @misc{MuellerGoryachkoBurkovetal., author = {M{\"u}ller, Klaus and Goryachko, Andriy and Burkov, Yevgen and Schwiertz, Carola and Ratzke, Markus and K{\"o}ble, J. and Reif, J{\"u}rgen and Schmeißer, Dieter}, title = {Scanning Kelvin Probe Microscopy and Photoemission electron microscopy of organic source-drain structures}, series = {Synthetic Metals}, volume = {146}, journal = {Synthetic Metals}, number = {3}, issn = {0379-6779}, pages = {377 -- 382}, abstract = {n order to optimize organic field effect transistors (OFETs), the characterisation of active-layer surfaces in terms of their roughness, chemical composition and distribution of surface potentials is important. We report on high-resolution microscopic mapping of organic source-drain structures with P3HT as the semiconductor by scanning Kelvin probe microscopy (SKPM) and photoemission electron microscopy (PEEM). It was shown that PEEM is able to characterise the surface morphology (roughness), the chemical homogeneity and the composition of organic structures. The two-dimensional mapping of surface potentials by SKPM with applied source-drain voltages is shown to be an important ingredient of OFETs failure mode analysis.}, language = {en} } @misc{RatzkeWolfframmKappaetal., author = {Ratzke, Markus and Wolfframm, Dirk and Kappa, Mathias and Kouteva-Arguirova, Simona and Reif, J{\"u}rgen}, title = {Pulsed laser deposition of HfO2 and Pr(x)O(y) high-k films on Si(100)}, series = {Applied Surface Science}, volume = {247}, journal = {Applied Surface Science}, number = {1-4}, issn = {0169-4332}, pages = {128 -- 133}, language = {en} } @misc{KappaRatzkeReif, author = {Kappa, Mathias and Ratzke, Markus and Reif, J{\"u}rgen}, title = {Pulsed laser deposition of hafnium oxide on silicon}, language = {en} } @inproceedings{LippertDabrowskiCostinaetal., author = {Lippert, Gunther and Dabrowski, Jarek Marek and Costina, Ioan and Lupina, Grzegorz and Ratzke, Markus and Zaumseil, Peter and M{\"u}ssig, Hans-Joachim}, title = {Morphology and Composition of Praseodymium Based High-k Materials and Their Relevance to Dielectric Properties of Thin-Films}, language = {en} } @misc{ReifCostacheVarlamovaetal., author = {Reif, J{\"u}rgen and Costache, Florenta Adriana and Varlamova, Olga and Jia, G. and Ratzke, Markus}, title = {Self-organized regular surface patterning by pulsed laser ablation}, series = {Physica Status Solidi C}, volume = {6}, journal = {Physica Status Solidi C}, number = {3}, issn = {1610-1634}, doi = {10.1002/pssc.200880719}, pages = {681 -- 686}, language = {de} } @misc{VarlamovaRatzkeReif, author = {Varlamova, Olga and Ratzke, Markus and Reif, J{\"u}rgen}, title = {Feedback Effect on the Self-Organized Nanostructures Formation on Silicon upon Femtosecond Laser Ablation}, series = {Solid State Phenomena}, volume = {156/158}, journal = {Solid State Phenomena}, issn = {1012-0394}, pages = {535 -- 540}, language = {en} } @article{ReifRatzkeVarlamovaetal., author = {Reif, J{\"u}rgen and Ratzke, Markus and Varlamova, Olga and Costache, Florenta Adriana}, title = {Electrical Properties of Laser-Ablation-Initiated Self-Organized Nanostructures on Silicon Surface}, doi = {10.1016/j.mseb.2006.07.030}, language = {en} } @inproceedings{RatzkeKappaWolfframmetal., author = {Ratzke, Markus and Kappa, Mathias and Wolfframm, Dirk and Kouteva-Arguirova, Simona and Reif, J{\"u}rgen}, title = {PLD of high-k dielectric films on silicon}, series = {Fifth International Symposium on Laser Precision Microfabrication, 11 - 14 May 2004, Nara, Japan}, booktitle = {Fifth International Symposium on Laser Precision Microfabrication, 11 - 14 May 2004, Nara, Japan}, publisher = {SPIE}, address = {Bellingham, Wash.}, isbn = {0-8194-5623-3}, pages = {406 -- 411}, language = {en} } @misc{RatzkeWolfframmArguirovetal., author = {Ratzke, Markus and Wolfframm, Dirk and Arguirov, Tzanimir V. and Kappa, Mathias and Reif, J{\"u}rgen}, title = {Pulsed laser deposition of Praseodymium Oxide films on Silicon (100)}, series = {Applied Physics / A}, volume = {79}, journal = {Applied Physics / A}, number = {4-6}, issn = {0947-8396}, pages = {1247 -- 1249}, language = {en} } @article{WolfframmRatzkeKappaetal., author = {Wolfframm, Dirk and Ratzke, Markus and Kappa, Mathias and Montenegro, M. J. and D{\"o}beli, M. and Lippert, Th. and Reif, J{\"u}rgen}, title = {Pulsed Laser Deposition of Thin PrxOx Films on Si(100)}, series = {Materials Science and Engineering B}, volume = {109}, journal = {Materials Science and Engineering B}, number = {1-3}, issn = {0921-5107}, pages = {24 -- 29}, language = {en} } @misc{ReifVarlamovaRatzkeetal., author = {Reif, J{\"u}rgen and Varlamova, Olga and Ratzke, Markus and Schade, Martin and Leipner, Hartmut S. and Arguirov, Tzanimir V.}, title = {Multipulse feedback in self-organized ripples formation upon femtosecond laser ablation from silicon}, series = {Applied Physics A}, volume = {101}, journal = {Applied Physics A}, number = {2}, issn = {0947-8396}, doi = {10.1007/s00339-010-5830-x}, pages = {361 -- 365}, language = {en} } @article{RatzkeYangReif, author = {Ratzke, Markus and Yang, B. and Reif, J{\"u}rgen}, title = {Fixed charge densitiy distribution on pulsed laser deposited high-k oxide layers}, language = {en} } @article{RatzkeYuVyvenkoetal., author = {Ratzke, Markus and Yu, Xuegong and Vyvenko, Oleg F. and Reif, J{\"u}rgen and Kittler, Martin and Reiche, Manfred}, title = {Scanning Probe studies of the electrical activity at interfaces formed by silicon wafer direct bonding}, series = {Physica Status Solidi C}, volume = {4}, journal = {Physica Status Solidi C}, number = {8}, issn = {1610-1634}, pages = {2893 -- 3897}, language = {en} } @article{RatzkeReif, author = {Ratzke, Markus and Reif, J{\"u}rgen}, title = {On the reliability of scanning probe based electrostatic force measurements}, language = {en} } @article{VarlamovaCostacheRatzkeetal., author = {Varlamova, Olga and Costache, Florenta Adriana and Ratzke, Markus and Reif, J{\"u}rgen}, title = {Control parameters in pattern formation upon femtosecond laser ablation}, language = {en} } @misc{SchmidMankovicsArguirovetal., author = {Schmid, Reiner P. and Mankovics, Daniel and Arguirov, Tzanimir V. and Ratzke, Markus and Mtchedlidze, T. and Kittler, Martin}, title = {Rapid dislocation-related D1-photoluminescence imaging of multicrystalline Si wafers at room temperature}, series = {Physica Status Solidi : A}, volume = {208}, journal = {Physica Status Solidi : A}, number = {4}, issn = {1610-1642}, doi = {10.1002/pssa.201026269}, pages = {888 -- 892}, language = {en} } @misc{YuArguirovKittleretal., author = {Yu, Xuegong and Arguirov, Tzanimir V. and Kittler, Martin and Seifert, Winfried and Ratzke, Markus and Reiche, Manfred}, title = {Properties of dislocation networks formed by Si wafer direct bonding}, series = {Materials Science in Semiconductor Processing}, volume = {9}, journal = {Materials Science in Semiconductor Processing}, number = {1-3}, doi = {10.1016/j.mssp.2006.01.070}, pages = {96 -- 101}, language = {en} } @misc{LippertDabrowskiOberbecketal., author = {Lippert, Gunther and Dabrowski, Jarek Marek and Oberbeck, Lars and Schroeder, Uwe and Costina, Ioan and Lupina, Grzegorz and Ratzke, Markus and Zaumseil, Peter and M{\"u}ssig, Hans-Joachim}, title = {Morphology and composition of selected high-k materials and their relevance to dielectric properties of thin films}, series = {Journal of the electrochemical society}, volume = {155}, journal = {Journal of the electrochemical society}, number = {5}, issn = {1945-7111}, doi = {10.1149/1.2875741}, pages = {G97 -- G114}, language = {en} } @misc{KlossekMankovicsArguirovetal., author = {Klossek, Andre and Mankovics, Daniel and Arguirov, Tzanimir V. and Ratzke, Markus and Kirner, Simon and Friedrich, Felice and Gabriel, Onno and Stannowski, Bernd and Schlatmann, Rutger and Kittler, Martin}, title = {Growth process of microcrystalline silicon studied by combined photoluminsescence and Raman investigations}, series = {Journal of applied physics}, volume = {114}, journal = {Journal of applied physics}, issn = {1520-8850}, doi = {10.1063/1.4838058}, pages = {223511}, language = {en} } @misc{ReifVarlamovaRatzkeetal., author = {Reif, J{\"u}rgen and Varlamova, Olga and Ratzke, Markus and Uhlig, Sebastian}, title = {Laser-Induced Periodic Surface Structures of Thin Complex Multi-Component Films}, series = {Applied Physics / A}, volume = {122}, journal = {Applied Physics / A}, number = {4}, issn = {1432-0630}, doi = {10.1007/s00339-016-9936-7}, pages = {1 -- 6}, language = {en} } @misc{VarlamovaMartensRatzkeetal., author = {Varlamova, Olga and Martens, Christian and Ratzke, Markus and Reif, J{\"u}rgen}, title = {Genesis of femtosecond-induced nanostructures on solid surfaces}, series = {Applied Optics}, volume = {53}, journal = {Applied Optics}, number = {31}, issn = {1539-4522}, pages = {I10 -- I15}, language = {en} } @misc{RatzkeMchedlidzeArguirovetal., author = {Ratzke, Markus and Mchedlidze, Teimuraz and Arguirov, Tzanimir V. and Acharya, N. and Kittler, Martin and Reif, J{\"u}rgen}, title = {Scanning probe studies of amorphous silicon subjected to laser annealing}, series = {Physica status solidi (C)}, volume = {8}, journal = {Physica status solidi (C)}, number = {4}, issn = {1610-1642}, pages = {1351 -- 1355}, language = {en} } @misc{CostacheRatzkeWolfframmetal., author = {Costache, Florenta Adriana and Ratzke, Markus and Wolfframm, Dirk and Reif, J{\"u}rgen}, title = {Femtosecond laser ionization mass spectrometric analysis of layers grown by pulsed laser deposition}, series = {Applied Surface Science}, volume = {247}, journal = {Applied Surface Science}, number = {1-4}, issn = {0169-4332}, pages = {249 -- 255}, language = {en} } @misc{MuellerGoryachkoBurkovetal., author = {M{\"u}ller, K. and Goryachko, Andriy and Burkov, Yevgen and Schwiertz, Carola and Ratzke, Markus and K{\"o}ble, J. and Reif, J{\"u}rgen and Schmeißer, Dieter}, title = {Scanning Kelvin probe and photoemission electron microscopy of organic source-drain structures}, series = {Synthetic Metals}, volume = {146}, journal = {Synthetic Metals}, number = {3}, pages = {377 -- 382}, language = {en} } @misc{ReifMartensUhligetal., author = {Reif, J{\"u}rgen and Martens, Christian and Uhlig, Sebastian and Ratzke, Markus and Varlamova, Olga and Valette, Stephane and Benayoun, Stephane}, title = {On large area LIPSS coverage by multiple pulses}, series = {Applied Surface Science}, volume = {336}, journal = {Applied Surface Science}, issn = {0169-4332}, doi = {doi:10.1016/j.apsusc.2014.11.153}, pages = {249 -- 254}, language = {en} } @misc{WolfframmRatzkeKoutevaArguirovaetal., author = {Wolfframm, Dirk and Ratzke, Markus and Kouteva-Arguirova, Simona and Reif, J{\"u}rgen}, title = {Praseodymium Oxide growth on Si(100) by pulsed laser deposition}, series = {Materials Science and Semiconductor Processing}, volume = {5}, journal = {Materials Science and Semiconductor Processing}, number = {4-5}, issn = {1369-8001}, pages = {429 -- 434}, language = {en} } @phdthesis{Ratzke, author = {Ratzke, Markus}, title = {Kraftmikroskopie als Werkzeug zur Charakterisierung elektrischer Oberfl{\"a}cheneigenschaften}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-24440}, pages = {169}, language = {de} } @misc{ObrosovGulyaevZaketal., author = {Obrosov, Aleksei and Gulyaev, Roman and Zak, Andrzej and Ratzke, Markus and Naveed, Muhammad and Dudzinski, Wlodzimierz and Weiß, Sabine}, title = {Chemical and Morphological Characterization of Magnetron Sputtered at Different Bias Voltages Cr-Al-C Coatings}, series = {Materials}, volume = {10}, journal = {Materials}, number = {2}, issn = {1996-1944}, doi = {10.3390/ma10020156}, pages = {156}, abstract = {MAX phases (M = transition metal, A = A-group element, and X = C/N) are of special interest because they possess a unique combination of the advantages of both metals and ceramics. Most attention is attracted to the ternary carbide Cr2AlC because of its excellent high-temperature oxidation, as well as hot corrosion resistance. Despite lots of publications, up to now the influence of bias voltage on the chemical bonding structure, surface morphology, and mechanical properties of the film is still not well understood. In the current study, Cr-Al-C films were deposited on silicon wafers (100) and Inconel 718 super alloy by dc magnetron sputtering with different substrate bias voltages and investigated using Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), and nanoindentation. Transmission Electron Microscopy (TEM) was used to analyze the correlation between the growth of the films and the coating microstructure. The XPS results confirm the presence of Cr2AlC MAX phase due to a negative shift of 0.6-0.9 eV of the Al2p to pure aluminum carbide peak. The XRD results reveal the presence of Cr2AlC MAX Phase and carbide phases, as well as intermetallic AlCr2. The film thickness decreases from 8.95 to 6.98 µm with increasing bias voltage. The coatings deposited at 90 V exhibit the lowest roughness (33 nm) and granular size (76 nm) combined with the highest hardness (15.9 GPa). The ratio of Al carbide to carbide-like carbon state changes from 0.12 to 0.22 and correlates with the mechanical properties of the coatings. TEM confirms the columnar structure, with a nanocrystalline substructure, of the films.}, language = {en} } @misc{ObrosovGulyaevRatzkeetal., author = {Obrosov, Aleksei and Gulyaev, Roman and Ratzke, Markus and Volinsky, Alex A. and Bolz, Sebastian and Naveed, Muhammad and Weiß, Sabine}, title = {XPS and AFM Investigations of Ti-Al-N Coatings Fabricated Using DC Magnetron Sputtering at Various Nitrogen Flow Rates and Deposition Temperatures}, series = {Metals}, volume = {7}, journal = {Metals}, number = {2}, issn = {2075-4701}, doi = {10.3390/met7020052}, pages = {52}, abstract = {Ti-Al-N coatings were deposited by direct current magnetron sputtering (DCMS) onto IN 718 at different nitrogen flow rates and deposition temperatures. The coatings' properties were characterized using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) as well as nanoindentation. It was found that higher deposition temperature leads to higher surface roughness and nitrogen flux influences the shape of grains. According to XPS, the bonding structure of all coatings exhibited the (Ti,Al)N phase. Mechanical properties depend on the Al content within the films. The coating with the best mechanical properties (deposited at 500 °C and 20 standard cubic centimeters per minute (sccm)) was further deposited onto tungsten carbide (WC) cutting tools for cylindrical turning experiments. A quasi-constant flank wear was observed until a machining volume of 23,500 mm³.}, language = {en} } @misc{RaziVarlamovaReifetal., author = {Razi, Sepehr and Varlamova, Olga and Reif, J{\"u}rgen and Bestehorn, Michael and Varlamov, Sergej and Mollabashi, Mahmoud and Madanipour, Khosro and Ratzke, Markus}, title = {Birth of periodic Micro/Nano structures on 316L stainless steel surface following femtosecond laser irradiation; single and multi scanning study}, series = {Optics \& Laser Technology}, volume = {104}, journal = {Optics \& Laser Technology}, issn = {0030-3992}, doi = {10.1016/j.optlastec.2018.02.001}, pages = {8 -- 16}, abstract = {Formation of coherent laser induced periodic surface structures (LIPSS) on stainless steel type 316L by 100 fs laser pulses at 800 nm wavelength is investigated. Specifically focusing on the large area treatment, effect of the irradiation dose (fluence × pulse number) on the uniformity of the morphology, orientation of the ripples respect to the laser polarization and their periodicity is studied systematically. Controlling the pulse number via varying the scanning speed, the difference between irradiating one particular dose in single scan with its irradiation in separate steps is inspected. Results clearly point out that not only the irradiation dose but also the irradiation way and the time delay between the pulse trains might have a significant effect on the final outcomes. It is discussed in detail that the experimental observations are supporting the model of self-organized structure formation due to irradiation induced instability.}, language = {en} } @misc{VarlamovaHoefnerRatzkeetal., author = {Varlamova, Olga and Hoefner, Kevin and Ratzke, Markus and Reif, J{\"u}rgen and Sarker, Debasish}, title = {Modification of surface properties of solids by femtosecond LIPSS writing: comparative studies on silicon and stainless steel}, series = {Applied Physics A}, volume = {123}, journal = {Applied Physics A}, number = {12}, issn = {0947-8396}, doi = {10.1007/s00339-017-1362-y}, pages = {6}, language = {en} } @misc{CzajkowskiRatzkeVarlamovaetal., author = {Czajkowski, Klaus and Ratzke, Markus and Varlamova, Olga and Reif, J{\"u}rgen}, title = {Femtosecond-laser-induced periodic surface structures on magnetic layer targets: The roles of femtosecond-laser interaction and of magnetization}, series = {Applied Surface Science}, volume = {417}, journal = {Applied Surface Science}, issn = {0169-4332}, doi = {10.1016/j.apsusc.2017.03.148}, pages = {84 -- 87}, language = {en} } @misc{OleynikBerkmannReiteretal., author = {Oleynik, Paul and Berkmann, Fritz and Reiter, Sebastian and Schlipf, Jon and Ratzke, Markus and Yamamoto, Yuji and Fischer, Inga Anita}, title = {Strong Optical Coupling of Lattice Resonances in a Top-down Fabricated Hybrid Metal-Dielectric Al/Si/Ge Metasurface}, series = {Nano Letters}, volume = {24}, journal = {Nano Letters}, number = {10}, issn = {1530-6984}, doi = {10.1021/acs.nanolett.3c05050}, pages = {3142 -- 3149}, abstract = {Optical metasurfaces enable the manipulation of the light-matter interaction in ultrathin layers. Compared with their metal or dielectric counterparts, hybrid metasurfaces resulting from the combination of dielectric and metallic nanostructures can offer increased possibilities for interactions between modes present in the system. Here, we investigate the interaction between lattice resonances in a hybrid metal-dielectric metasurface obtained from a single-step nanofabrication process. Finite-difference time domain simulations show the avoided crossing of the modes appearing in the wavelength-dependent absorptance inside the Ge upon variations in a selected geometry parameter as evidence for strong optical coupling. We find good agreement between the measured and simulated absorptance and reflectance spectra. Our metasurface design can be easily incorporated into a top-down optoelectronic device fabrication process with possible applications ranging from on-chip spectroscopy to sensing.}, language = {en} } @misc{NitschRatzkePozarowskaetal., author = {Nitsch, Paul-G. and Ratzke, Markus and Pozarowska, Emilia and Flege, Jan Ingo and Alvarado Chavarin, Carlos and Wenger, Christian and Fischer, Inga Anita}, title = {Deposition of reduced ceria thin films by reactive magnetron sputtering for the development of a resistive gas sensor}, series = {Verhandlungen der DPG, Berlin 2024}, journal = {Verhandlungen der DPG, Berlin 2024}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, abstract = {The use of cerium oxide for hydrogen sensing is limited by the low electrical conductivity of layers deposited from a ceria target. To increase the electrical conductivity, partially reduced cerium oxide layers were obtained from a metallic cerium target by reactive magnetron sputtering. The proportions of the oxidation states Ce3+, present in reduced species, and Ce4+, present in fully oxidized species, were determined by ex-situ XPS. For electrical characterization, films were deposited on planarized tungsten finger electrodes. IV curves were measured over several days to investigate possible influences of oxygen and humidity on electrical conductivity. The morphological stability of the layers under ambient conditions was investigated by microscopical methods. The XPS results show a significant amount of Ce3+ in the layers. The electrical conductivity of as-grown samples is several orders of magnitude higher than that of samples grown from a ceria target. However, the conductivity decreases over time, indicating an oxidation of the layers. The surface morphology of the samples was found to be changing drastically within days, leading to partial delamination.}, language = {en} } @misc{KostoTschammerMoralesetal., author = {Kosto, Yuliia and Tschammer, Rudi and Morales, Carlos and Henkel, Karsten and Flege, Jan Ingo and Ratzke, Markus and Fischer, Inga Anita and Costina, Ioan and Alvarado Chavarin, Carlos and Wenger, Christian}, title = {Rational design and development of room temperature hydrogen sensors compatible with CMOS technology: a necessary step for the coming renewable hydrogen economy}, series = {Proceedings of iCampus Conference Cottbus 2024}, journal = {Proceedings of iCampus Conference Cottbus 2024}, publisher = {AMA Service GmbH}, address = {Wunstorf}, isbn = {978-3-910600-00-3}, doi = {10.5162/iCCC2024/P21}, pages = {182 -- 185}, abstract = {The transition towards a new, renewable energy system based on green energy vectors, such as hydrogen, requires not only direct energy conversion and storage systems, but also the development of auxiliary components, such as highly sensitive hydrogen gas sensors integrated into mass devices that operate at ambient conditions. Despite the recent advances in nanostructured metal oxide thin films in terms of simple fabrication processes and compatibility with integrated circuits, high sensitivity, and short response/recovery times usually require the use of expensive noble metals or elevated tem-peratures (>250 ºC), which results in high power consumption and poor long-term stability. This article presents the first steps of the work on developing a novel resistive hydrogen gas sensor based on ultrathin cerium oxide films, compatible with complementary metal oxide semiconductor technology and capable of operating at room temperature. Here, we show a multidisciplinary bottom-up approach combining different work areas for the sensor development, such as sensor architecture, sensing mechanism and deposition strategy of the active layer, electrical contact design depending on the desired electrical output, and fast testing under controlled environments.}, language = {en} } @misc{EisenhauerFrankWeigeltetal., author = {Eisenhauer, Nico and Frank, Karin and Weigelt, Alexandra and Bartkowski, Bartosz and Beugnon, R{\´e}my and Liebal, Katja and Mahecha, Miguel and Quaas, Martin and Al-Halbouni, Djamil and Bastos, Ana and Bohn, Friedrich J. and Brito, Mariana Madruga de and Denzler, Joachim and Feilhauer, Hannes and Fischer, Rico and Fritsche, Immo and Guimaraes-Steinicke, Claudia and H{\"a}nsel, Martin and Haun, Daniel B. M. and Herrmann, Hartmut and Huth, Andreas and Kalesse-Los, Heike and Koetter, Michael and Kolleck, Nina and Krause, Melanie and Kretschmer, Marlene and Leit{\~a}o, Pedro J. and Masson, Torsten and Mora, Karin and M{\"u}ller, Birgit and Peng, Jian and P{\"o}hlker, Mira L. and Ratzke, Leonie and Reichstein, Markus and Richter, Solveig and R{\"u}ger, Nadja and S{\´a}nchez-Parra, Beatriz and Shadaydeh, Maha and Sippel, Sebastian and Tegen, Ina and Thr{\"a}n, Daniela and Umlauft, Josefine and Wendisch, Manfred and Wolf, Kevin and Wirth, Christian and Zacher, Hannes and Zaehle, S{\"o}nke and Quaas, Johannes}, title = {A belowground perspective on the nexus between biodiversity change, climate change, and human well-being}, series = {Journal of Sustainable Agriculture and Environment}, volume = {3}, journal = {Journal of Sustainable Agriculture and Environment}, number = {2}, publisher = {Wiley}, issn = {2767-035X}, doi = {10.1002/sae2.12108}, pages = {12}, abstract = {Soil is central to the complex interplay among biodiversity, climate, and society. This paper examines the interconnectedness of soil biodiversity, climate change, and societal impacts, emphasizing the urgent need for integrated solutions. Human-induced biodiversity loss and climate change intensify environmental degradation, threatening human well-being. Soils, rich in biodiversity and vital for ecosystem function regulation, are highly vulnerable to these pressures, affecting nutrient cycling, soil fertility, and resilience. Soil also crucially regulates climate, influencing energy, water cycles, and carbon storage. Yet, climate change poses significant challenges to soil health and carbon dynamics, amplifying global warming. Integrated approaches are essential, including sustainable land management, policy interventions, technological innovations, and societal engagement. Practices like agroforestry and organic farming improve soil health and mitigate climate impacts. Effective policies and governance are crucial for promoting sustainable practices and soil conservation. Recent technologies aid in monitoring soil biodiversity and implementing sustainable land management. Societal engagement, through education and collective action, is vital for environmental stewardship. By prioritizing interdisciplinary research and addressing key frontiers, scientists can advance understanding of the soil biodiversity-climate change-society nexus, informing strategies for environmental sustainability and social equity.}, language = {en} } @misc{ReiterRatzkeNitschetal., author = {Reiter, Sebastian and Ratzke, Markus and Nitsch, Paul-Gregor and Mai, Christian and Spirito, Davide and Corley-Wiciak, Agnieszka Anna and Wenger, Christian and Fischer, Inga A.}, title = {Optical response of titanium nitride plasmonic nanohole arrays : impact of square and hexagonal array geometry, pitch, and nanohole diameter}, series = {Plasmonics}, volume = {20}, journal = {Plasmonics}, publisher = {Springer}, address = {New York, NY}, doi = {10.1007/s11468-025-02934-4}, pages = {8825 -- 8834}, abstract = {Plasmonic nanohole arrays (NHAs) exhibit extraordinary optical transmission (EOT) evoked by resonant excitation of surface plasmons at an excitation wavelength, which is highly sensitive to changes in refractive index in the surrounding dielectric. This can enable the use of plasmonic NHAs in on-chip refractive index sensors. Such sensors can be realized on the cost-effective silicon platform by the integration of a plasmonic NHA and a Ge photodetector, provided that complementary metal-oxide-semiconductor (CMOS)-compatible materials are used for their fabrication. Titanium nitride (TiN) as a biocompatible and CMOS-compatible plasmonic transition metal nitride is well-suited for integration on the silicon platform; however, the comparatively large losses within the material require geometry optimization strategies in order to improve the optical properties of TiN NHAs for sensing. In this work, we investigated different TiN NHA geometries both in experiment and simulation. We extensively characterized square and hexagonal arrays with varying pitches and nanohole diameters and provide a detailed comparison of their optical properties. We also discuss characterization results for surface refractive index changes imposed by depositing a thin Al2O3 layer on top of the NHAs. While we do not observe a clear advantage of hexagonal arrays compared to square arrays for sensing, our results highlight the importance of geometry optimization for TiN NHAs integrated with devices.}, language = {en} } @misc{SenguelReiterLotfietal., author = {Seng{\"u}l, Akant and Reiter, Sebastian and Lotfi, Zahra and Efremenko, Julia and Laroussi, Arwa and Corley-Wiciak, Agnieszka Anna and Ratzke, Markus and Mirsky, Vladimir M. and Wenger, Christian and Fischer, Inga Anita}, title = {Titanium nitride plasmonic nanohole arrays with polymer coating : optical properties and their humidity-induced modifications}, series = {Optical materials express}, volume = {16}, journal = {Optical materials express}, number = {2}, publisher = {Optica Publishing Group}, address = {Washington, DC}, issn = {2159-3930}, doi = {10.1364/ome.578871}, pages = {184 -- 196}, abstract = {The use of titanium nitride (TiN) for the fabrication of plasmonic structures such as nanohole arrays (NHAs) can enable their integration into optoelectronic devices on the silicon (Si) platform, for example, for the realization of on-chip chemical sensors and biosensors based on refractometric transduction. With a corresponding functionalization of the TiN nanohole arrays, these ultra-compact devices can be utilized in the development of various affinity sensors and sensor systems, such as cost-effective electronic noses for the early detection of gases in the food industry or agriculture. In this work, we focus on two types of coating for functionalization of TiN nanohole arrays: electrochemically synthesized poly-N-methylaniline and layer-by-layer deposited polyacrylic-acid/poly-allylamine (PAA/PAH). Our investigation comprises the experimental characterization of the optical properties of TiN nanhole arrays coated with polymer layers of different thicknesses as well as a comparison with simulation results. We demonstrate the potential of our setup sensing applications by measuring changes in optical properties of TiN nanohole arrays coated with PAA/PAH upon exposure to air of different humidity.}, language = {en} }