@misc{KovalLazarevaMuelleretal., author = {Koval, Yuri and Lazareva, I. and M{\"u}ller, P. and M{\"u}ller, Klaus and Henkel, Karsten and Friedrich, Daniel}, title = {Field effect transistors on graphitized polymer surfaces}, language = {en} } @misc{LazarevaKovalMuelleretal., author = {Lazareva, I. and Koval, Yuri and M{\"u}ller, P. and M{\"u}ller, Klaus and Henkel, Karsten and Schmeißer, Dieter}, title = {Interface screening and imprint in pol(vinylidene fluoride/trifluoroethylene) ferroelectric field effect transistors}, language = {en} } @misc{HenkelLazarevaMandaletal., author = {Henkel, Karsten and Lazareva, I. and Mandal, Dipankar and Paloumpa, Ioanna and M{\"u}ller, Klaus and Koval, Yuri and M{\"u}ller, P. and Schmeißer, Dieter}, title = {Electrical investigations on metal/ferroelectric/insulator/semiconductor structures using Poly[vinylidene fluoride trifluoroethylene] as ferroelectric layer for organic nonvolatile memory applications}, language = {en} } @inproceedings{LazarevaKovalMuelleretal., author = {Lazareva, I. and Koval, Yuri and M{\"u}ller, P. and Paloumpa, Ioanna and M{\"u}ller, Klaus and Schmeißer, Dieter}, title = {Field effect transistor of graphitized polyimide with P(VDF-TrFE) as gate insulator}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 43}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 43}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, pages = {S. 195}, abstract = {Surfaces of polyimide films were graphitized by low-energy ion irradiation. The conductivity was between 10-5 to 200 S/cm [1]. We prepared field effect transistors using this material. Ferroelectric P(VDF-TrFE) was used as gate insulator. The thickness of P(VDF-TrFE) varied from 120 nm to 1200 nm. Properties of P(VDF-TrFE) were investigated by current-voltage measurements of metal/ P(VDF-TrFE)/metal capacitors. We have found that at room temperature, the coercive field of P(VDF-TrFE) does not depend on the film thickness. At lower temperatures the coercive field increases proportionally to the reciprocal temperature. Remnant polarization is 9.5 µC/cm2. It slightly rises with decreasing temperature. Our recent results of field effect mobility, carrier concentration and threshold voltage are presented. [1] I. Lazareva, Y. Koval, M. Alam, S. Str{\"o}msd{\"o}rfer, P. M{\"u}ller, Appl. Phys. Lett. 90, 262108 (2007)}, language = {en} } @inproceedings{SchmeisserMuellerHenkeletal., author = {Schmeißer, Dieter and M{\"u}ller, Sebastian and Henkel, Karsten and M{\"u}ller, Klaus and Wehner, Stefan}, title = {In-situ analysis of moving reaction fronts for the bistable CO oxidation reaction on noble metal catalyst}, series = {Extended Abstracts Book of First International Conference on Materials for Energy}, booktitle = {Extended Abstracts Book of First International Conference on Materials for Energy}, publisher = {Dechema e.V.}, address = {Frankfurt}, isbn = {978-3-89746-117-8}, pages = {S. 932}, abstract = {Experimental data on the reaction kinetics of catalytic processes are prerequisite for modeling of such reactions and their output. We investigate the CO oxidation on some noble metal catalysts, like Iridium(111) and Palladium(111) which is a bistable surface reaction. In a specific range of CO content in the feed gas islands of one or the other adsorbate nucleate and grow, which is recorded with photo electron emission microscopy (PEEM). During these transients the coverage on the surface changes from predominantly oxygen covered to predominantly CO covered resp. vice versa. But the resolution of PEEM and especially its unknown and nonlinear dependence of coverage of the two adsorbates (oxygen and CO) and image intensity make it impossible to extract the changes in coverage. On the other hand the reaction diffusion model based on the Langmuir-Hinshelwood-mechanism delivers the coverage of oxygen and carbon monoxide. The shapeand wall velocity of those islands has been connected perfectly to each other [CPL 423 (2006) 39], but not the absolute coverage and their variation during the reaction. Since the domain wall velocity is small on Iridium(111), this has opened the possibility for a detailed analysis of the changing coverage inside this domain wallutilizing synchrotron radiation and photo electron spectroscopy at BESSY II. The coverage profile of oxygen and CO inside a moving domain wall was measured for both cases using XPS spectra at O1s, C1s and the valence band during thereaction. Comparison with the reaction-diffusion-model and other catalytic surfaces, like Palladium(111) are done.}, language = {en} } @misc{MuellerTorgerAllertzetal., author = {M{\"u}ller, Felix and Torger, Bernhard and Allertz, Peter J. and J{\"a}hnichen, Klaus and Keßler, Stefan and M{\"u}ller, Martin and Simon, Frank and Salchert, Katrin and M{\"a}urer, Haike and Pospiech, Doris}, title = {Multifunctional crosslinkable itaconic acid copolymers for enzyme immobilization}, series = {European Polymer Journal}, volume = {102}, journal = {European Polymer Journal}, doi = {10.1016/j.eurpolymj.2018.03.014}, pages = {47 -- 55}, abstract = {UV-Crosslinkable itaconic copolymers are developed to provide new multifunctional materials for coatings which combine crosslinkable functionalities and the possibility to immobilize enzymes. The polymer-immobilized enzymes were used for water treatment to decompose persistent organic molecules. Introduction of suitable comonomers allows tailoring the mechanical and chemical properties for special applications. Copolymers containing MMA and itaconic anhydride were chosen because of the formation of long-term stable anhydride functionalities. These anhydride functionalities are employed to attach enzymes covalently. 4-Benzoylphenyl methacrylate is used as comonomer for UV-initiated crosslinking. Terpolymers are successfully obtained by radical copolymerization in solution. The copolymers are compared to poly(ethylene-alt-maleic anhydride) [P(EMA)] often used with respect to enzyme immobilization, activity and hydrolytic stability. The hydrolysis stability of the copolymers against water is studied by ATR-FTIR spectroscopy. Thin films are prepared on glass substrates in a layer-by-layer procedure by spin-coating. The layer formation is monitored by ATR-FTIR spectroscopy. UV-crosslinking of the copolymer films is performed taking the optimal irradiation dose that avoids polymer degradation. ATR-FTIR spectroscopy verifies the coupling reaction between amino groups of the enzyme and the anhydride groups on the surface of the crosslinked polymer film. The syringaldazine (4-hydroxy-3,5-dimethoxybenzaldehyde azine) test and 2,2´-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assay demonstrate that the immobilized enzymes maintain their activities. The functional copolymers showed a significant effect in reduction of persistent organic pollutants in contaminated waste water.}, language = {de} } @misc{BochAllanBirkhoferetal., author = {Boch, Steffen and Allan, Eric and Birkhofer, Klaus and Bossdorf, Oliver and Bl{\"u}thgen, Nico and Christ-Breulmann, Sabina and Diek{\"o}tter, Tim and Dormann, Carsten F. and Gossner, Martin M. and Hallmann, Christine and Hemp, Andreas and H{\"o}lzel, Norbert and Jung, Kirsten and Klaus, Valentin H. and Klein, Alexandra M. and Kleinebecker, Till and Lange, Markus and M{\"u}ller, J{\"o}rg and Nacke, Heiko and Prati, Daniel and Renner, Swen C. and Rothenw{\"o}hrer, Christoph and Schall, Peter and Schulze, Ernst-Detlef and Socher, Stephanie A. and Tscharntke, Teja and T{\"u}rke, Manfred and Weiner, Christiane N. and Weisser, Wolfgang W. and Westphal, Catrin and Wolters, Volkmar and Wubet, Tesfaye and Fischer, Markus}, title = {Extensive und j{\"a}hrlich wechselnde Nutzungsintensit{\"a}t f{\"o}rdert den Artenreichtum im Gr{\"u}nland}, series = {ANLIEGEN NATUR}, volume = {38}, journal = {ANLIEGEN NATUR}, number = {1}, issn = {1864-0729}, pages = {86 -- 95}, language = {de} } @misc{NeyretLeProvostBoesingetal., author = {Neyret, Margot and Le Provost, Ga{\"e}tane and Boesing, Andrea Larissa and Schneider, Florian D. and Baulechner, Dennis and Bergmann, Joana and Vries, Franciska T. de and Fiore-Donno, Anna Maria and Geisen, Stefan and Goldmann, Kezia and Merges, Anna and Saifutdinov, Ruslan A. and Simons, Nadja K. and Tobias, Joseph A. and Zaitsev, Andrey S. and Gossner, Martin M. and Jung, Kirsten and Kandeler, Ellen and Krauss, Jochen and Penone, Caterina and Schloter, Michael and Schulz, Stefanie and Staab, Michael and Wolters, Volkmar and Apostolakis, Antonios and Birkhofer, Klaus and Boch, Steffen and Boeddinghaus, Runa S. and Bolliger, Ralph and Bonkowski, Michael and Buscot, Fran{\c{c}}ois and Dumack, Kenneth and Fischer, Markus and Gan, Huei Ying and Heinze, Johannes and H{\"o}lzel, Norbert and John, Katharina and Klaus, Valentin H. and Kleinebecker, Till and Marhan, Sven and M{\"u}ller, J{\"o}rg and Renner, Swen C. and Rillig, Matthias C. and Schenk, No{\"e}lle V. and Sch{\"o}ning, Ingo and Schrumpf, Marion and Seibold, Sebastian and Socher, Stephanie A. and Solly, Emily F. and Teuscher, Miriam and Kleunen, Mark van and Wubet, Tesfaye and Manning, Peter}, title = {A slow-fast trait continuum at the whole community level in relation to land-use intensification}, series = {Nature Communications}, volume = {15}, journal = {Nature Communications}, number = {1}, issn = {2041-1723}, doi = {10.1038/s41467-024-45113-5}, abstract = {AbstractOrganismal functional strategies form a continuum from slow- to fast-growing organisms, in response to common drivers such as resource availability and disturbance. However, whether there is synchronisation of these strategies at the entire community level is unclear. Here, we combine trait data for 2800 above- and belowground taxa from 14 trophic guilds spanning a disturbance and resource availability gradient in German grasslands. The results indicate that most guilds consistently respond to these drivers through both direct and trophically mediated effects, resulting in a 'slow-fast' axis at the level of the entire community. Using 15 indicators of carbon and nutrient fluxes, biomass production and decomposition, we also show that fast trait communities are associated with faster rates of ecosystem functioning. These findings demonstrate that 'slow' and 'fast' strategies can be manifested at the level of whole communities, opening new avenues of ecosystem-level functional classification.}, language = {en} } @misc{MuellerHenkelMikaloetal., author = {M{\"u}ller, Klaus and Henkel, Karsten and Mikalo, Ricardo Pablo and Paloumpa, Ioanna and Schmeißer, Dieter}, title = {Elektronik mit organischen Materialien}, publisher = {BTU Cottbus, Eigenverlag}, abstract = {Plastikelektronik, flexible Solarzellen, intelligente Kleidung, neuartige und maßgeschneiderte Transducer f{\"u}r die Gas-, Fl{\"u}ssigkeits- und Biosensorik, all dies sind Anwendungen, die ohne halbleitende Polymere nicht denkbar w{\"a}ren und die Bereiche erschließen, in denen zur Zeit eine regelrechte Goldgr{\"a}berstimmung herrscht. Mit wichtigen Beitr{\"a}gen im Grundlagen- und Anwendungsbereich nimmt die BTU Cottbus an dieser Entwicklung teil, u. a. auch durch eine Kooperation mit dem Institut f{\"u}r Mikrobiologie des Carl-Thiem-Klinikums Cottbus.In diesem Artikel werden die Voraussetzungen f{\"u}r die Konstruktion organischer Feldeffekt-Transistoren mit gassensitiver Gate-Elektrode vorgestellt. Untersuchungen zur elektronischen Struktur des organischen Halbleiters Poly(3-Hexylthiophen), die Anwendung dieses Materials als aktive Schicht in organischen Feldeffekt-Transitoren, die Gassensitivit{\"a}t von Polypyrrolelektroden auf Quarz-Mikrowaagen und die Mikrorstukturierung organischer Elektroden werden beschrieben.}, language = {de} } @inproceedings{MuellerHenkelPaloumpaetal., author = {M{\"u}ller, Klaus and Henkel, Karsten and Paloumpa, Ioanna and Schmeißer, Dieter}, title = {Low-cost-Plot-Technologie fur die Mikrostrukturierung von Gassensoren}, series = {Sensoren im Fokus neuer Anwendungen, 5. Dresdner Sensor-Symposium, 10. - 12. Dezember 2001, Dresden}, booktitle = {Sensoren im Fokus neuer Anwendungen, 5. Dresdner Sensor-Symposium, 10. - 12. Dezember 2001, Dresden}, publisher = {w.e.b. Universit{\"a}tsverlag}, address = {Dresden}, isbn = {3-935712-71-5}, pages = {166 -- 169}, abstract = {Bei der Herstellung von Mikrosensoren ist die Strukturierung von Elektroden oder elektrischen Zu-leitungen mit einem hohen Miniaturisierungsgrad ein entscheidender Punkt. Dazu m{\"u}s-sen h{\"a}ufig teure Verfahren (Lithographie, Maskentechniken) herangezogen werden.Dieser Beitrag beschreibt eine low-cost-Technologie zur Herstellung organischer Mikrostrukturen f{\"u}r elektronische und messtechnische Anwendungen im Bereich der Sensorik. Geplottete Strukturen mit Polypyrrol und Poly(3,4-Ethylen-Dioxy-Thiophen), dotiert mit Polystyrolsulfonat (PEDOT/PSS) wurden als Widerstandssensoren f{\"u}r die Detektion von Luftfeuchte ein-gesetzt. Die prinzipielle Ein-satzm{\"o}glichkeit unserer Technik im Bereich der organischen Elektronik konnten wir mit dem Bau organischer Feldeffekttransistoren nachweisen. Mit einem computergesteu-erten Plotter des Typs Rol-land DXY-1150A, Plot-Kapillaren f{\"u}r das Tuschezeichnen, handels{\"u}blichen Folien f{\"u}r wasserl{\"o}sliche Tinten als Substrat und kolloidalen Graphit als leitendes Material konnten wir Aufl{\"o}sungen, das heißt insbesondere Kanalbreiten bzw. Elektrodenabst{\"a}nde im Bereich von 20+10\%B5m (auf 2cm L{\"a}nge) her-stellen.}, language = {de} } @article{MuellerHoffmannMilkoetal., author = {M{\"u}ller, Klaus and Hoffmann, Patrick and Milko, S. and Burkov, Yevgen and Schmeißer, Dieter}, title = {PEEM and µ-NEXAFS of Cu-In-S-Surfaces}, abstract = {The composition of CuInS2-films tends to differ from the ideal ratio of 1:1:2. A molecularlyvariation of dm=[Cu]/[In]-1 not equal 0 occurs due to the formation of binary phases as segregation's at the surface, as crystallites in the bulk of the film or at the surface of grains [1]. Furthermore, the range of homogeneity of the phase CuInS2 is relatively large caused by a low enthalpy of formation of defects like Cu-vacancies [2]. Segregation's at surfaces can be removed by KCN etching or by an electrochemical process [3, 4] We investigated the effect of an in-situ-heat-treatment of samples, prepared in the Cu-rich regime with additional amounts of copper, deposited on the surface of the Cu-In-S-films.We used Cu-In-S-films on molybdenum, prepared from precursors of Cu/In and a following reactive annealing-process in a sulphur-atmosphere. The experiments were performed as follows: The surface of the films was cleaned in situ to remove CuS-Phases by Argon-bombardment. The thin layers of additional Copper were prepared by evaporation of copper metal in Knudsen-cells. The thickness of this copper-films is in the range of monolayers, revealed by a calibration with copper on iron-substrates. After this deposition the samples were heated up to several temperatures (up to 550 ºC) for ten minutes, respectively. Here the molybdenum back-contact was used as electrical heater.}, language = {en} } @article{MuellerMilkoSchmeisser, author = {M{\"u}ller, Klaus and Milko, S. and Schmeißer, Dieter}, title = {Preparation of stoichiometric CuInS2-surfaces - an XPS, UPS-study}, series = {Thin Solid Films}, volume = {431-432}, journal = {Thin Solid Films}, issn = {0040-6090}, pages = {312 -- 316}, abstract = {CuInS2 films are investigated with photoelectron spectroscopy. We find significant deviation from the stoichiometric composition depending on the preparation on the films. For Cu-rich films (start composition) we show that by Ar sputtering and annealing the surface composition varies along a binary cut of the Cu-In-S ternary phase diagram. We also present a novel technique which brings the surface composition close to the stoichiometric stability range of the CuInS2 phase. The technique used the evaporation of Cu on the sputter cleaned surface.}, language = {en} } @misc{MuellerBurkovSchmeisser, author = {M{\"u}ller, Klaus and Burkov, Yevgen and Schmeißer, Dieter}, title = {PEEM and my-NEXAFS of Cu-In-S2-surfaces}, series = {Thin Solid Films}, volume = {431-432}, journal = {Thin Solid Films}, issn = {0040-6090}, pages = {307 -- 311}, abstract = {Polycrystalline CuInS2 samples are an ideal system for photoemission electron microscope studies. The polycrystalline grains have a diameter of approximately 5 small mu, Greekm and the system is expected to be highly inhomogeneous because of the existence of many sub-phases. We used a recently established procedure to reproducibly obtain stoichiometric CuInS2-surfaces and follow the changes in the morphology, the elemental inhomogeneous distribution, and the development of the electronic structure upon its preparation. We find that the individual grains trend to coagulate, the surface composition becomes more homogeneous, and identify characteristic features of the unoccupied DOS.}, language = {en} } @misc{MuellerPaloumpaSchmeisser, author = {M{\"u}ller, Klaus and Paloumpa, Ioanna and Schmeißer, Dieter}, title = {Carbon-plot-microstructuring for all-polymer-transistors}, series = {Synthetic Metals}, volume = {138}, journal = {Synthetic Metals}, number = {1-2}, issn = {0379-6779}, pages = {271 -- 273}, abstract = {This contribution describes the use of a low-cost technology to produce organic microstructures for electronically applications. With a computer driven plotter, substrates like printing foil and colloidal graphite (diluted in water) for the electrodes, we realised channel lengths of 20±10 microm. Compared with transistor devices, fabricated using conventional photolithographic methods and the same semiconducting material, this technique is a hopeful approach to produce microelectronic structures that are low-cost and all-organic.}, language = {en} } @incollection{MuellerBaerHenkeletal., author = {M{\"u}ller, Klaus and B{\"a}r, Werner and Henkel, Karsten and Jahnke, Agnes and Schwiertz, Carola and Schmeißer, Dieter}, title = {Organische Feldeffekttransistoren als Transducer in der Biosensorik}, publisher = {w.e.b.-Univ.-Verl.}, address = {Dresden}, isbn = {3-935712-92-8}, pages = {119 -- 223}, language = {de} } @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} } @article{Mueller, author = {M{\"u}ller, Klaus}, title = {PEEM studies of KCN-etched CuInS2 surfaces}, language = {de} } @article{Mueller, author = {M{\"u}ller, Klaus}, title = {PEEM imaging contrast in an operating organic electronic device}, language = {en} } @article{Mueller, author = {M{\"u}ller, Klaus}, title = {Spectro-Microscopic Characterisation of CuInS2 Surfaces}, abstract = {hotoemission electron microscopy (PEEM) is used to study CuInS2 surfaces. CuInS2 (CIS) is used as polycrystalline absorber layer for thin film solar cells. A characterisation in terms of morphological information, elemental distribution, and of doping inhomogeneities at the surface is very important. We demonstrate that the method is capable for such surface studies in high lateral resolution. The use of synchrotron radiation allows the visualization of chemical inhomogeneities in single grains. By taking PEEM images around the absorption edges of Cu, In, or S, we are able to map elemental distributions, separated from morphology-dependent information in the PEEM image.}, language = {en} } @misc{MuellerPaloumpaHenkeletal., author = {M{\"u}ller, Klaus and Paloumpa, Ioanna and Henkel, Karsten and Schmeißer, Dieter}, title = {A polymer high-k dielectric insulator for organic field effect Transistors}, series = {Journal of Applied Physics}, volume = {98}, journal = {Journal of Applied Physics}, number = {5}, issn = {0021-8979}, pages = {S. 056104}, language = {en} } @misc{HenkelSohalTorcheetal., author = {Henkel, Karsten and Sohal, Rakesh and Torche, Mohamed and Paloumpa, Ioanna and M{\"u}ller, Klaus and Hoffmann, Patrick and Schmeißer, Dieter}, title = {Grenzfl{\"a}chenoptimierung f{\"u}r funktionale D{\"u}nnschichtsysteme: Oxide und Polymere}, series = {Forum der Forschung}, volume = {9}, journal = {Forum der Forschung}, number = {18}, issn = {0947-6989}, pages = {49 -- 56}, language = {de} } @article{MuellerScheerSchmeisseretal., author = {M{\"u}ller, Klaus and Scheer, R. and Schmeißer, Dieter and Burkov, Yevgen}, title = {Preparation of stoichiometric CuInS2-Surfaces}, series = {Thin Solid Films}, volume = {451-452}, journal = {Thin Solid Films}, issn = {0040-6090}, pages = {120 -- 123}, language = {en} } @article{MuellerBurkovSchmeisser, author = {M{\"u}ller, Klaus and Burkov, Yevgen and Schmeißer, Dieter}, title = {Photo-Emission-Electron-Microscopy for Characterization of an Operating Organic Electronic Device}, language = {en} } @article{MuellerPaloumpaSchmeisseretal., author = {M{\"u}ller, Klaus and Paloumpa, Ioanna and Schmeißer, Dieter and Henkel, Karsten}, title = {Organic thin film transistors with polymer high-k dielectric insulator}, language = {en} } @article{MuellerHenkelSchmeisser, author = {M{\"u}ller, Klaus and Henkel, Karsten and Schmeißer, Dieter}, title = {Organic field effect transistors with ferroelectric hysteresis}, language = {en} }