TY - GEN A1 - Müller, Klaus A1 - Henkel, Karsten A1 - Mikalo, Ricardo Pablo A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter T1 - Elektronik mit organischen Materialien N2 - Plastikelektronik, flexible Solarzellen, intelligente Kleidung, neuartige und maßgeschneiderte Transducer für die Gas-, Flüssigkeits- und Biosensorik, all dies sind Anwendungen, die ohne halbleitende Polymere nicht denkbar wären und die Bereiche erschließen, in denen zur Zeit eine regelrechte Goldgräberstimmung herrscht. Mit wichtigen Beiträgen im Grundlagen- und Anwendungsbereich nimmt die BTU Cottbus an dieser Entwicklung teil, u. a. auch durch eine Kooperation mit dem Institut für Mikrobiologie des Carl-Thiem-Klinikums Cottbus.In diesem Artikel werden die Voraussetzungen für 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 Gassensitivität von Polypyrrolelektroden auf Quarz-Mikrowaagen und die Mikrorstukturierung organischer Elektroden werden beschrieben. Y1 - 2002 PB - BTU Cottbus, Eigenverlag ER - TY - CHAP A1 - Schwiertz, Carola A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter T1 - Sensorsystem zur Unterscheidung von Geruchsmustern in Tierställen N2 - Es wurde ein kontinuierlich arbeitendes, preiswertes Schwingquarz-Mess-System zur olfaktometrischen Überwachung von Tierställen aufgebaut, mit dessen Hilfe im Arbeitsbereich von 65%B0C spezifische Gerüche verschiedener Tierarten unterschieden werden können. Zur Geruchsmustererkennung wurde ein einfaches neuronales Netz verwendet. Olfaktometrische Verdünnungen auf 33% sowie Messwertschwankungen von 5-10% wurden simuliert, wobei die richtige Musterzuordnung durch das Netz nicht beeinflusst wurde. Y1 - 2002 ER - TY - CHAP A1 - Henkel, Karsten A1 - Hoffmann, Patrick A1 - Schmeißer, Dieter T1 - Backpropagation-Netzwerke für ein Zweisensorsystem zur Erfassung von Kohlendioxidkonzentrationen und relativer Luftfeuchte T2 - Sensoren im Fokus neuer Anwendungen : Verbraucherschutz und Lebensmittelkontrolle, Biosysteme und Nanobiotechnologie, Umweltmesstechnik, neue Sensormaterialien, Mess- und Eichwesen N2 - Zwei Schwingquarzsensoren mit gleicher sensitiver Beschichtung wurden zur Messung von CO2-Konzentrationen bei variierenden Luftfeuchten genutzt. Die Daten wurden neuronalen Netzen mit unterschiedlicher Architektur trainiert. Zwei Netze wurden auf ihre Generalisierungsfähigkeit getestet und miteinander verglichen. Für ein einstufiges Netz konnten Ergebnisse mit Fehlern kleiner 12% für die CO2-Konzentration und kleiner 5% für die Luftfeuchte erzielt werden. Ein zweistufiges Netz erkannte Kategorien der Luftfeuchte 100%-ig, für die CO2-Konzentration wurden Fehler kleiner 9% erreicht, wobei eine deutlich bessere Generalisierungsfähigkeit dieses Netzes im Vergleich zum einstufigen Netz zu verzeichnen ist. Y1 - 2002 SN - 3-935712-71-5 SN - 978-3-935712-71-2 SP - 104 EP - 107 PB - w.e.b. Universitätsverlag CY - Dresden ER - TY - CHAP A1 - Müller, Klaus A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter T1 - Low-cost-Plot-Technologie fur die Mikrostrukturierung von Gassensoren T2 - Sensoren im Fokus neuer Anwendungen, 5. Dresdner Sensor-Symposium, 10. - 12. Dezember 2001, Dresden N2 - Bei der Herstellung von Mikrosensoren ist die Strukturierung von Elektroden oder elektrischen Zu-leitungen mit einem hohen Miniaturisierungsgrad ein entscheidender Punkt. Dazu müs-sen häufig teure Verfahren (Lithographie, Maskentechniken) herangezogen werden.Dieser Beitrag beschreibt eine low-cost-Technologie zur Herstellung organischer Mikrostrukturen für 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 für die Detektion von Luftfeuchte ein-gesetzt. Die prinzipielle Ein-satzmöglichkeit 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 für das Tuschezeichnen, handelsüblichen Folien für wasserlösliche Tinten als Substrat und kolloidalen Graphit als leitendes Material konnten wir Auflösungen, das heißt insbesondere Kanalbreiten bzw. Elektrodenabstände im Bereich von 20+10%B5m (auf 2cm Länge) her-stellen. Y1 - 2002 SN - 3-935712-71-5 SP - 166 EP - 169 PB - w.e.b. Universitätsverlag CY - Dresden ER - TY - CHAP A1 - Cura, Christian A1 - Ewert, H. A1 - Henke, Ingo A1 - Henkel, Karsten A1 - Schubert, Rainer T1 - Ausbreitungseigenschaften akustischer Oberflächenwellen auf LiNbO3 bei tiefen Temperaturen T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft ; Reihe 6, Bd. 33 Y1 - 1998 SN - 0420-0195 SP - S. 987 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - GEN A1 - Henkel, Karsten A1 - Oprea, A. A1 - Paloumpa, Ioanna A1 - Appel, Günter A1 - Schmeißer, Dieter A1 - Kamieth, P. T1 - Selective polypyrrole electrodes for quartz microbalances : NO2 and gas flux sensitivities T2 - Sensors and Actuators : B, Chemical 76(2001)1-3 Y1 - 2001 SN - 0925-4005 VL - 76 IS - 1-3 SP - 124 EP - 129 ER - TY - CHAP A1 - Henkel, Karsten A1 - Elling, B. A1 - Danz, R. A1 - Büchtemann, A. A1 - Straube, Oliver A1 - Paloumpa, Ioanna A1 - Yfantis, Alexandros D. A1 - Schmeißer, Dieter T1 - Piezoelectric polymer sensor for high pressures in forming machines Y1 - 2001 UR - http://www.materialsweek.org/proceedings/index.htm ER - TY - CHAP A1 - Müller, Klaus A1 - Bär, Werner A1 - Henkel, Karsten A1 - Jahnke, Agnes A1 - Schwiertz, Carola A1 - Schmeißer, Dieter T1 - Organische Feldeffekttransistoren als Transducer in der Biosensorik Y1 - 2003 SN - 3-935712-92-8 SP - 119 EP - 223 PB - w.e.b.-Univ.-Verl. CY - Dresden ER - TY - CHAP A1 - Henkel, Karsten A1 - Schwiertz, Carola A1 - Wagner, S. A1 - Valdeig, A. A1 - List, M. A1 - Schmeißer, Dieter T1 - Partikel- und Tropfendetektion im Mikrometerbereich mittels Schwingquarzen Y1 - 2003 SN - 3-935712-92-8 SP - 291 EP - 294 PB - w.e.b.-Univ.-Verl. CY - Dresden ER - TY - JOUR A1 - Goryachko, Andriy A1 - Yeromenko, Y. A1 - Henkel, Karsten A1 - Wollweber, Jürgen A1 - Schmeißer, Dieter T1 - The Si(001)/C2H2 interaction to form a buffer layer for 3C-SiC growth JF - Physica status solidi / A N2 - The intial stages of Si(001) interaction with C2H2 were investigated with XPS and surface profilometry. The carbon enriched layer serves as a buffer between Si substrate and the 3C-SiC film aimed at growing on Si(001). Such parameters as substrate temperature and process duration come into a complicated interplay of C deposition, its reaction with Si and out-diffusion of the later from the substrate. Three distinct regimes, namely graphite dominated, carbide dominated and roughness dominated are found to result from this interplay. Y1 - 2004 SN - 0031-8965 VL - 201 IS - 2 SP - 245 EP - 248 ER - TY - GEN A1 - Müller, Klaus A1 - Paloumpa, Ioanna A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - A polymer high-k dielectric insulator for organic field effect Transistors T2 - Journal of Applied Physics Y1 - 2005 SN - 0021-8979 VL - 98 IS - 5 SP - S. 056104 ER - TY - GEN A1 - Henkel, Karsten A1 - Sohal, Rakesh A1 - Torche, Mohamed A1 - Paloumpa, Ioanna A1 - Müller, Klaus A1 - Hoffmann, Patrick A1 - Schmeißer, Dieter T1 - Grenzflächenoptimierung für funktionale Dünnschichtsysteme: Oxide und Polymere T2 - Forum der Forschung Y1 - 2005 SN - 0947-6989 VL - 9 IS - 18 SP - 49 EP - 56 ER - TY - JOUR A1 - Müller, Klaus A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter A1 - Henkel, Karsten T1 - Organic thin film transistors with polymer high-k dielectric insulator KW - high-k Y1 - 2006 ER - TY - JOUR A1 - Torche, Mohamed A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - The interaction of Al, Ag, Au and Ti to Pr2O3 thin film dielectrics KW - thin films KW - Pr2O3 Y1 - 2006 ER - TY - JOUR A1 - Henkel, Karsten A1 - Sohal, Rakesh A1 - Schmeißer, Dieter A1 - Schwiertz, Carola A1 - Burkov, Yevgen A1 - Torche, Mohamed T1 - Al-oxynitride buffer layer facilities for PrOx/SiC interfaces Y1 - 2007 ER - TY - JOUR A1 - Müller, Klaus A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Organic field effect transistors with ferroelectric hysteresis Y1 - 2007 ER - TY - JOUR A1 - Schmeißer, Dieter A1 - Burkov, Yevgen A1 - Paloumpa, Ioanna A1 - Mandal, Dipankar A1 - Henkel, Karsten T1 - Microscopic and Spectroscopic Characterization of Interfaces and Dielectric Layers for OFET Devices Y1 - 2008 ER - TY - JOUR A1 - Schmeißer, Dieter A1 - Henkel, Karsten A1 - Karavaev, Konstantin T1 - Al-Oxynitride Interfacial Layer Investigations for PrxOy on SiC and Si Y1 - 2008 ER - TY - GEN A1 - Henkel, Karsten A1 - Torche, Mohamed A1 - Sohal, Rakesh A1 - Karavaev, Konstantin A1 - Burkov, Yevgen A1 - Schwiertz, Carola A1 - Schmeißer, Dieter T1 - Pr-O-Al-N dielectrics for metal insulator semiconductor stacks KW - semiconductor KW - dielectric Y1 - 2011 ER - TY - GEN A1 - Müller, Klaus A1 - Henkel, Karsten A1 - Mandal, Dipankar A1 - Seime, Bernd A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter T1 - Spin coated organic ferroelectric films for non volatile memories KW - organic KW - ferroelectric Y1 - 2011 ER - TY - GEN A1 - Koval, Yuri A1 - Lazareva, I. A1 - Müller, P. A1 - Müller, Klaus A1 - Henkel, Karsten A1 - Friedrich, Daniel T1 - Field effect transistors on graphitized polymer surfaces KW - transistors KW - polymer Y1 - 2011 ER - TY - GEN A1 - Mandal, Dipankar A1 - Henkel, Karsten A1 - Müller, Klaus A1 - Schmeißer, Dieter T1 - Band gab determination of P(VDF-TrFE) copolymer film by electron energy loss spectroscopy Y1 - 2010 ER - TY - GEN A1 - Henkel, Karsten A1 - Seime, Bernd A1 - Paloumpa, Ioanna A1 - Müller, Klaus A1 - Schmeißer, Dieter T1 - Buffer layer incestigaions on MFIS capacitors consisting of ferroelectric poly[vinylidene fluoride trifluoroethylene] T2 - IOP conference series : Materials Science and Engineering KW - MFIS capacitors KW - ferroelectric Y1 - 2010 SN - 1757-899X VL - 8 IS - 1 SP - 012036 ER - TY - GEN A1 - Schmeißer, Dieter A1 - Henkel, Karsten A1 - Bergholz, Matthias A1 - Tallarida, Massimo T1 - The band gab and band offset in ultrathin oxide-semiconductor heterostructures KW - band gab KW - offset KW - ultrathin KW - heterostructures Y1 - 2010 ER - TY - CHAP A1 - Schwiertz, Carola A1 - Henkel, Karsten A1 - Blei, S. A1 - Heidenreich, R. A1 - Schmeißer, Dieter T1 - Nachweis von Aerosolen (<1µm) mit Schwingquarzimpedanzspektroskopie KW - Schwingquarzimpedanzspektroskopie Y1 - 2009 ER - TY - GEN A1 - Schmeißer, Dieter A1 - Henkel, Karsten A1 - Müller, Klaus A1 - Tallarida, Massimo T1 - Interface Reactions in Ultrathin Functional Dielectric Films KW - ultrathin KW - dielectric Y1 - 2009 ER - TY - GEN A1 - Schmeißer, Dieter A1 - Tallarida, Massimo A1 - Henkel, Karsten A1 - Müller, Klaus A1 - Mandal, Dipankar A1 - Chumakov, Dmytro A1 - Zschech, Ehrenfried T1 - Characterization of oxidic and organic materials with synchrotron radiation based XPS and XAS KW - oxidic KW - organic KW - materials KW - synchrotron radiation KW - XPS KW - XAS Y1 - 2009 ER - TY - GEN A1 - Lazareva, I. A1 - Koval, Yuri A1 - Müller, P. A1 - Müller, Klaus A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Interface screening and imprint in pol(vinylidene fluoride/trifluoroethylene) ferroelectric field effect transistors KW - interface KW - screening KW - transistors Y1 - 2009 ER - TY - CHAP A1 - Müller, Klaus A1 - Burkov, Yevgen A1 - Mandal, Dipankar A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Goryachko, Andriy A1 - Schmeißer, Dieter ED - Wöll, Christof T1 - Microscopic and spectroscopic characterization of interfaces and dielectric layers for OFET devices T2 - Organic Electronics : structural and Electronic Properties of OFETs KW - microscopic KW - spectrocsopic KW - dielectric Y1 - 2009 SN - 978-3-527-40810-8 SP - 445 EP - 468 PB - Wiley-VCH CY - Weinheim ER - TY - GEN A1 - Henkel, Karsten A1 - Lazareva, I. A1 - Mandal, Dipankar A1 - Paloumpa, Ioanna A1 - Müller, Klaus A1 - Koval, Yuri A1 - Müller, P. A1 - Schmeißer, Dieter T1 - Electrical investigations on metal/ferroelectric/insulator/semiconductor structures using Poly[vinylidene fluoride trifluoroethylene] as ferroelectric layer for organic nonvolatile memory applications KW - metal KW - frerroelectric KW - insulator KW - semiconductor Y1 - 2009 ER - TY - GEN A1 - Henkel, Karsten A1 - Burkov, Yevgen A1 - Karavaev, Konstantin A1 - Torche, Mohamed A1 - Schwiertz, Carola A1 - Schmeißer, Dieter T1 - Optimization of the AION buffer layer for PrxOy/Si stacks KW - AION buffer Y1 - 2009 ER - TY - JOUR A1 - Müller, Klaus A1 - Mandal, Dipankar A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter T1 - Ferroelectric properties of spin-coated ultrathin (down to 10nm) copolymer films KW - ferroelectric KW - spin-coated KW - copolymer Y1 - 2008 ER - TY - CHAP A1 - Henkel, Karsten A1 - Burkov, Yevgen A1 - Bergholz, Matthias A1 - Karavaev, Konstantin A1 - Sohal, Rakesh A1 - Torche, Mohamed A1 - Schmeißer, Dieter T1 - Al-Oxynitride as a buffer layer for high-k dielectrics T2 - Proceedings of 15th Workshop on Dielectrics in Microelectronics, Bad Saarow, 23 - 25 June 2008, Bad Saarow (Berlin) KW - buffer layer KW - high-k KW - dielectric Y1 - 2008 SP - 161 EP - 162 ER - TY - CHAP A1 - Henkel, Karsten A1 - Mandal, Dipankar A1 - Seime, Bernd A1 - Paloumpa, Ioanna A1 - Lazareva, I. A1 - Müller, Klaus A1 - Schmeißer, Dieter T1 - Electrical investigations on MFIS structures consisting P[VDF/TrFE] as ferro-electric layer for non-volatile memory applications T2 - Proceedings of 15th Workshop on Dielectrics in Microelectronics, Bad Saarow, 23 - 25 June 2008, Bad Saarow (Berlin) KW - MFIS, P[VDF/TrFE] KW - ferroelectric KW - non-volatile Y1 - 2008 SP - 159 EP - 160 ER - TY - CHAP A1 - Broczkowska, K. A1 - Klocek, Jolanta A1 - Friedrich, Daniel A1 - Henkel, Karsten A1 - Kolanek, Krzysztof A1 - Urbanowicz, A. A1 - Schmeißer, Dieter A1 - Miller, M. A1 - Zschech, Ehrenfried T1 - Fullerene based materials for ultra-low-k application T2 - International Students and Young Scientists Workshop "Photonics and Microsystems", Szklarska, Poreba, Poland, 25 - 27 June 2010 Y1 - 2010 SN - 978-1-4244-8324-2 SP - 39 EP - 43 PB - IEEE CY - Piscataway, NJ ER - TY - GEN A1 - Henkel, Karsten A1 - Seime, Bernd A1 - Paloumpa, Ioanna A1 - Müller, Klaus A1 - Schmeißer, Dieter T1 - Optimization of MFIS structures containing poly(vinylidene-fluoride trifluoroethylene) for non-volatile memory applications Y1 - 2010 ER - TY - GEN A1 - Henkel, Karsten A1 - Seime, Bernd A1 - Paloumpa, Ioanna A1 - Müller, Klaus A1 - Schmeißer, Dieter T1 - Buffer layer investigations on MFIS capacitors consisting of ferroelectric poly[vinylidene fluoride trifluoroethylene] Y1 - 2010 ER - TY - GEN A1 - Mandal, Dipankar A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Comment on "Preparation and Characterization of Silver-Poly(vinylidene fluoride) Nanocomposites:Formation of Piezoelectric Polymorph of Poly(vinylidene fluoride" Y1 - 2011 ER - TY - JOUR A1 - Henkel, Karsten A1 - Karavaev, Konstantin A1 - Torche, Mohamed A1 - Schwiertz, Carola A1 - Burkov, Yevgen A1 - Schmeißer, Dieter T1 - Al-Oxyxynitride interfacial layer investigations for PrXOY on SiC and Si Y1 - 2008 ER - TY - CHAP A1 - Henkel, Karsten A1 - Torche, Mohamed A1 - Sohal, Rakesh A1 - Schwiertz, Carola A1 - Hoffmann, Patrick A1 - Schmeißer, Dieter ED - Dudley, Michael T1 - Pr-O-N Dielectrics for MIS Stacks on Silicon and Silicon Carbide Surfaces T2 - Silicon carbide 2006 - materials, processing and devices, symposium held April 18 - 20, 2006, San Francisco, California, U.S.A. Y1 - 2006 SN - 978-1-55899-867-4 SP - 353 EP - 358 PB - Materials Research Society CY - Warrendale, Pa. ER - TY - JOUR A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Back-propagation based neural network with a two sensor system for monitoring of carbon dioxide and relative humidity Y1 - 2002 ER - TY - RPRT A1 - Schwiertz, Carola A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter A1 - Kamieth, P. A1 - Schnegber, P. T1 - Aufbau eines Sensorarrays zur Detektion von umwelt- und tierphysiologisch relevanten Komponenten Y1 - 2001 ER - TY - RPRT A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Schwiertz, D. A1 - Schmeißer, Dieter A1 - Kamieth, P. A1 - Schengber, P. T1 - Gezielte Entwicklung von Sensormaterialien und Sensoren zur spezifischen Detektion von schwefel- und stickstoffhaltigen Stoffgruppen Y1 - 2001 ER - TY - JOUR A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Schwiertz, B. A1 - Elling, B. A1 - Danz, R. A1 - Büchtemann, A. A1 - Straube, Oliver A1 - Schmeißer, Dieter T1 - Kraftsensoren aus Polymerfolien-Piezoelektrische Polymersensoren für Hochdruckanwendungen Y1 - 2001 ER - TY - RPRT A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Oprea, A. A1 - Appel, Günter A1 - Schmeißer, Dieter A1 - Frandsen, W. A1 - Schölzel, Mario T1 - Entwicklung von Sensoren mit Elektroden aus leitfähigen Polymeren Y1 - 2000 N1 - Teilbericht 16SV335/7 im Gemeinsamen Abschlussbericht zum Verbundprojekt "Sensoren mit mikrostrukturierten Elektroden aus leitfähigen Polymeren", März 2000, Kurzfassung ER - TY - JOUR A1 - Appel, Günter A1 - Mikalo, Ricardo Pablo A1 - Henkel, Karsten A1 - Oprea, A. A1 - Yfantis, Alexandros D. A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter T1 - Polymeric Electrodes Y1 - 2000 ER - TY - JOUR A1 - Oprea, A. A1 - Henkel, Karsten A1 - Oehmgen, R. A1 - Appel, Günter A1 - Schmeißer, Dieter A1 - Lauer, H. A1 - Hausmann, P. T1 - Increased sensor sensitivities obtained by polymer coated quartz microbalances Y1 - 1999 ER - TY - GEN A1 - Friedrich, Daniel A1 - Henkel, Karsten A1 - Richter, Matthias A1 - Schmeißer, Dieter T1 - Fullerenol as probed by Synchrotron X-Ray Photoemission and Absorption Spectroscopy Y1 - 2011 ER - TY - CHAP A1 - Mandal, Dipankar A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Control of the Crystalline Polymorph, Molecular Dipole and Chain Orientations in P(VDF-HFP) for High Electrical Energy Storage Application T2 - International Conference on Nanoscience, Technology and Societal Implications (NSTSI), 2011 Y1 - 2012 SN - 978-1-4577-2035-2 U6 - https://doi.org/10.1109/NSTSI.2011.6111801 PB - IEEE ER - TY - GEN A1 - Klocek, Jolanta A1 - Henkel, Karsten A1 - Kolanek, Krzysztof A1 - Broczkowska, K. A1 - Schmeißer, Dieter A1 - Miller, M. A1 - Zschech, Ehrenfried T1 - Studies of the chemical and electrical properties of fullerene and 3-aminopropyltrimethoxysilane based low-k materials T2 - Thin Solid Films Y1 - 2012 SN - 0040-6090 VL - 520 IS - 7 SP - 2498 EP - 2504 ER - TY - GEN A1 - Mandal, Dipankar A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - The electroactive Beta-phase formation in Poly(vinylidene fluoride) by gold nanoparticles doping T2 - Materials Letters Y1 - 2012 SN - 0167-577X IS - 73 SP - 123 EP - 125 ER - TY - GEN A1 - Klocek, Jolanta A1 - Henkel, Karsten A1 - Kolanek, Krzysztof A1 - Zschech, Ehrenfried A1 - Schmeißer, Dieter T1 - Annealing influence on siloxane based materials incorporated with fullerenes, phthalocyanines and silsesquioxanes T2 - BioNanoScience Y1 - 2012 SN - 2191-1630 VL - 2 IS - 1 SP - 52 EP - 58 ER - TY - GEN A1 - Klocek, Jolanta A1 - Henkel, Karsten A1 - Kolanek, Krzysztof A1 - Zschech, Ehrenfried A1 - Schmeißer, Dieter T1 - Spectroscopic and capacitance-voltage characterization of thin aminopropylmethoxysilane films doped with copper phthalocyanine, tris(dimethylvinylsilyloxy)-POSS and fullerene cages T2 - Applied surface science Y1 - 2012 SN - 0169-4332 VL - 258 IS - 10 SP - 4213 EP - 4221 ER - TY - GEN A1 - Klocek, Jolanta A1 - Kolanek, Krzysztof A1 - Henkel, Karsten A1 - Zschech, Ehrenfried A1 - Schmeißer, Dieter T1 - Influence of the fullerene derivatives and cage polyhedral oligomeric silsesquioxanes on 3-aminopropyltrimethoxysilane based hybrid nanocomposites chemical, morphological and electrical properties T2 - Journal of Physics and Chemistry of Solids N2 - In this study we produced 3-aminopropyltrimethoxysilane based hybrid nanocomposites using fullerene derivative [6,6]–phenyl–C61–butyric acid methyl ester (PCBM) as nanodopants. Additionally, we modified obtained material with incompletely condensed cage polyhedral oligomeric silsesqiuox-anes (POSS) in order to improve its properties. Thin films were deposited by means of the spin-coating method. The films were characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and capacitance–voltage (CV) measurements. We observed that a properly chosen PCBM concentration may be a crucial factor to obtain high quality APTMS based films by the spin-coating technique. XPS revealed the presence of the C-NH-C species within POSS containing films indicating chemical interaction between the amino group of APTMS and the POSS molecules. AFM results suggest that at high POSS monomer concentration in the range of 1% the creation of fractal-shaped aggregates takes place. The CV characterization of the samples exhibits a decrease of the APTMS based films dielectric constant due to the POSS and PCBM contribution. The combination of the applied methods delivers complementary information concerning the properties of the analyzed films. KW - low-k KW - fullerene KW - aminopropyltrimethoxysilane KW - silsesqiuoxane KW - X-ray photoelectron spectroscopy (XPS) KW - Atomic force microscopy (AFM) KW - Capacitance voltage (CV) Y1 - 2013 U6 - https://doi.org/10.1016/j.jpcs.2012.08.013 SN - 0022-3697 VL - 74 IS - 1 SP - 135 EP - 145 ER - TY - GEN A1 - Mandal, Dipankar A1 - Müller, Klaus A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - The effect of X-ray photoelectron spectroscopy measurement on P(VDF-TrFE) copolymer thin films T2 - Applied Surface Science N2 - The impact of prolonged X-ray irradiation during X-ray photoelectron spectroscopy (XPS) measurement was investigated on poly(vinylidene-trifluoroethylene) (P(VDF-TrFE)) thin films. It was observed that prolonged X-ray irradiation can accelerate the crosslinking of P(VDF-TrFE) and diminish the ferroelectric phase. Fourier transform infrared spectroscopy (FT-IR) data indicate that the ferroelectric phase diminishes completely after 360 kJ of X-ray irradiation dose and it induces the paraelectric phase. In this work, the main emphasis was given to the optimization of the X-ray irradiation dose during XPS measurements to maintain the ferroelectric phase within the copolymer films. KW - P(VDF-TrFE) copolymer thin film KW - XPS measurement KW - X-ray irradiation KW - Ferroelectric to paraelectric phase transformation Y1 - 2012 U6 - https://doi.org/10.1016/j.apsusc.2012.07.144 SN - 0169-4332 SN - 1873-5584 IS - 261 SP - 209 EP - 213 ER - TY - CHAP A1 - Mandal, Dipankar A1 - Henkel, Karsten A1 - Das, Suken A1 - Schmeißer, Dieter ED - Heber, Jörg ED - Schlom, Darrell ED - Tokura, Yoshinori ED - Waser, Rainer ED - Wuttig, Matthias T1 - Control of β- and γ-Phase formation in electroactive P(VDF-HFP) films by silver nano-particle doping T2 - Frontiers in Electronic Materials: A Collection of Extended Abstracts of the Nature Conference Frontiers in Electronic Materials, June 17 to 20 2012, Aachen, Germany KW - P(VDF.HFP) KW - electroactive phase KW - nanoparticle doping KW - FTIR Y1 - 2012 SN - 978-3-527-41191-7 U6 - https://doi.org/10.1002/9783527667703.ch69 SP - 640 EP - 641 PB - Wiley-VCH CY - Weinheim ER - TY - THES A1 - Henkel, Karsten T1 - Electrical Investigations on Praseodymium Oxide/Aluminum Oxynitride Containing Metal-Insulator-Semiconductor Stacks and on Metal-Ferroelectric-Insulator-Semiconductor Structures Consisting of Poly[vinylidene fluoride trifluoroethylene] N2 - In this thesis electrical characterizations on metal-insulator-semiconductor (MIS) and metal-ferroelectric-insulator-semiconductor (MFIS) stacks are presented. The results are discussed in terms of the increase of the performance of these stacks in order to optimize the characteristics of devices like the field effect transistor (FET) for logic applications and the ferroelectric field effect transistor (FeFET) for non-volatile and non-destructive readout memory applications. Therefor, two material classes are investigated. Firstly, this work focuses on praseodymium oxide (PrxOy) films as a high-kmaterial on silicon (Si) and silicon carbide in MISsamples. In particular the improvement of the performance by the introduction of an aluminum oxynitride buffer layer, which acts as an interdiffusion barrier and reduces the leakage current, the interface state density and the equivalent oxide thickness, is demonstrated. Secondly, in this work the very attractive ferroelectric material poly[vinylidene fluoride trifluoroethylene] (P[VDF/TrFE]) is introduced in MFIS stacks on Si. The way of successive improvements of the MFIS stack is extensively discussed. Here, the optimization of the preparation of the samples as well as of the layer parameters in the sequence of the MFIS stacks is depicted. An improved long time stability of the memory functionof the MFIS stack with a partially optimized layer sequence is exhibited. The electrical results are correlated to spectroscopic findings on both material systems. Strong interfacial reactions between the PrxOy and Si as well as between the aluminum electrode and the P[VDF/TrFE] layer are observed. For both systems the importance of a buffer layer is discussed and its optimization is addressed, too. On both systems a very nice, as consistent, chain of improvements is shown caused by the spectroscopic controlled preparation combined with electrical measurements in order to obtain the functionality of a given material system. KW - Pr2O3 KW - P(VDF-TrFE) KW - capacitance-voltage KW - conductance-voltage KW - current-voltage KW - dielectric properties KW - high-k KW - feFET Y1 - 2009 SN - 978-3-8322-8404-6 PB - Shaker CY - Aachen ER - TY - GEN A1 - Haeberle, Jörg A1 - Henkel, Karsten A1 - Gargouri, Hassan A1 - Naumann, Franziska A1 - Gruska, Bernd A1 - Arens, Michael A1 - Tallarida, Massimo A1 - Schmeißer, Dieter T1 - Ellipsometry and XPS comparative studies of thermal and plasma enhanced atomic layer deposited Al2O3-films T2 - Beilstein Journal of Nanotechnology N2 - We report on results on the preparation of thin (<100 nm) aluminum oxide (Al2O3) films on silicon substrates using thermal atomic layer deposition (T-ALD) and plasma enhanced atomic layer deposition (PE-ALD) in the SENTECH SI ALD LL system. The T-ALD Al2O3layers were deposited at 200 °C, for the PE-ALD films we varied the substrate temperature range between room temperature (rt) and 200 °C. We show data from spectroscopic ellipsometry (thickness, refractive index, growth rate) over 4” wafers and correlatethem to X-ray photoelectron spectroscopy (XPS) results. The 200°C T-ALD and PE-ALD processes yield films with similar refractive indices and with oxygen to aluminum elemental ratios very close to the stoichiometric value of 1.5. However, in both also fragments of the precursor are integrated into the film. The PE-ALD films show an increased growth rate and lower carbon contaminations. Reducing the deposition temperature down to rt leads to a higher content of carbon and CH-species. We also find a decrease of the refractive index and of the oxygen to aluminum elemental ratio as well as an increase of the growth rate whereas the homogeneity of the film growth is not influenced significantly. Initial state energy shifts in all PE-ALD samples are observed which we attribute to a net negative charge within the films. KW - Al2O3 KW - ALD KW - ellipsometry KW - PE-ALD KW - XPS Y1 - 2013 U6 - https://doi.org/10.3762/bjnano.4.83 SN - 2190-4286 VL - 2013 IS - 4 SP - 732 EP - 742 ER - TY - GEN A1 - Henkel, Karsten A1 - Gargouri, Hassan A1 - Gruska, Bernd A1 - Arens, Michael A1 - Tallarida, Massimo A1 - Schmeißer, Dieter T1 - Capacitance and conductance versus voltage characterization of Al2O3 layers prepared by PE-ALD at 25°C ≤ T ≤ 200°C T2 - Journal of Vacuum Science and Technology A N2 - In this work, plasma enhanced atomic layer deposited (PE-ALD) samples were prepared at substrate temperatures in the range between room temperature (RT) and 200 °C and investigated by capacitance–voltage and conductance–voltage recordings. The measurements are compared to standard thermal atomic layer deposition (T-ALD) at 200 °C. Very low interface state density (D it) ~1011 eV−1 cm−2 could be achieved for the PE-ALD process at 200 °C substrate temperature after postdeposition anneal (PDA) in forming gas at 450 °C. The PDA works very effectively for both the PE-ALD and T-ALD at 200 °C substrate temperature delivering also similar values of negative fixed charge density (N fix) around −2.5 × 1012 cm−2. At the substrate temperature of 150 °C, highest N fix (−2.9 × 1012 cm−2) and moderate D it (2.7 × 1011 eV−1 cm−2) values were observed. The as deposited PE-ALD layer at RT shows both low D it in the range of (1 to 3) × 1011 eV−1 cm−2 and low N fix (−4.4 × 1011 cm−2) at the same time. The dependencies of N fix, D it, and relative permittivity on the substrate temperatures and its adjustability are discussed. KW - Atomic layer deposition (ALD) KW - Al2O3 KW - dielectric properties KW - interface state density KW - fixed oxide charge KW - permittivity Y1 - 2014 UR - http://link.aip.org/link/?JVA/32/01A107&aemail=author U6 - https://doi.org/10.1116/1.4831897 VL - 1 IS - 32 SP - 01A107-1 EP - 01A107-10 ER - TY - CHAP A1 - Henkel, Karsten A1 - Tallarida, Massimo A1 - Haeberle, Jörg A1 - Gargouri, Hassan A1 - Naumann, Franziska A1 - Gruska, Bernd A1 - Arens, Michael A1 - Schmeißer, Dieter ED - Glück, Bernhard K. ED - Schmidt, Sindy ED - Stein, Erhard ED - Raschke, Jörg-Uwe ED - Richter, Hans T1 - PE-ALD-Al2O3-Schichten für die Passivierung von Solarzellen T2 - Tagungsband Photovoltaik-Meeting: Anwendungen-Qualität-Perspektiven, Senftenberg, 16.04.2014 N2 - Dünne Al2O3-Schichten wurden bei Substrattemperaturen zwischen Raumtemperatur und 200°C mittels PE-ALD auf Si-Substraten abgeschieden und ellipsometrisch, spektroskopisch und elektrisch charakterisiert. Ihr Potenzial für die chemische und Feldeffektpassivierung der Oberflächenrekombination wird bewertet. KW - Al2O3 KW - Atomlagenabscheidung (ALD) KW - Passivierung KW - PE-ALD KW - negative fixe Oxidladungen Y1 - 2014 SP - 7 EP - 14 PB - Cottbus-Senftenberg CY - BTU ER - TY - GEN A1 - Mandal, Dipankar A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Improved performance of a polymer nanogenerator based on silver nanoparticles doped electrospun P(VDF–HFP) nanofibers T2 - Physical Chemistry Chemical Physics N2 - We report on the electrospinning of poly(vinylidene fluoride–hexafluoropropylene) [P(VDF–HFP)] nanofibers doped with silver nanoparticles for the preparation of a polymer based nanogenerator (PNG). It has been found that the yield of the piezoelectric phase is increased by the addition of silver nanoparticles. Furthermore, defects in the P(VDF–HFP) electrospun fibers are removed resulting in a significant enhancement in the output power of the PNG. A maximum generated PNG output voltage of 3 V with a current density of 0.9 μA cm−2 is achieved. KW - piezoelectric thin polymer film KW - FTIR KW - nanogenerator KW - PVDF KW - P(VDF-HFP) KW - nanofibers Y1 - 2014 U6 - https://doi.org/10.1039/C3CP55238A SN - 1463-9084 SN - 1463-9076 VL - 2014 IS - 16 SP - 10403 EP - 10407 ER - TY - GEN A1 - Das, Chittaranjan A1 - Henkel, Karsten A1 - Tallarida, Massimo A1 - Schmeißer, Dieter A1 - Gargouri, Hassan A1 - Kärkkänen, Irina A1 - Schneidewind, Jessica A1 - Gruska, Bernd A1 - Arens, Michael T1 - Thermal and plasma enhanced atomic layer deposition of TiO2: Comparison of spectroscopic and electric properties T2 - Journal of Vacuum Science and Technology A N2 - Titanium oxide (TiO2) deposited by atomic layer deposition (ALD) is used as a protective layer in photocatalytic water splitting system as well as a dielectric in resistive memory switching. The way ALD is performed (thermally or plasma-assisted) may change the growth rate as well as the electronic properties of the deposited films. In the present work, the authors verify the influence of the ALD mode on functional parameters, by comparing the growth rate and electronic properties of TiO2 films deposited by thermal (T-) and plasma-enhanced (PE-) ALD. The authors complete the study with the electrical characterization of selected samples by means of capacitance–voltage and current–voltage measurements. In all samples, the authors found a significant presence of Ti3+ states, with the lowest content in the PE-ALD grown TiO2 films. The observation of Ti3+ states was accompanied by the presence of in-gap states above the valence band maximum. For films thinner than 10 nm, the authors found also a strong leakage current. Also in this case, the PE-ALD films showed the weakest leakage currents, showing a correlation between the presence of Ti3+ states and leakage current density. KW - titanium oxide (TiO2) KW - atomic layer deposition KW - plasma enhanced atomic layer deposition KW - synchrotron radiation photoelectron spectroscopy (SR-PES) KW - x-ray absorption spectroscopy KW - capacitance-voltage (CV) KW - current-voltage (IV) KW - ellipsometry KW - in-gap states Y1 - 2015 U6 - https://doi.org/10.1116/1.4903938 SN - 1520-8559 SN - 0734-2101 VL - 2015 IS - 33 SP - 01A144-1 EP - 01A144-8 ER - TY - GEN A1 - Garain, Samiran A1 - Sinha, Tridib Kumar A1 - Adhikary, Prakriti A1 - Henkel, Karsten A1 - Sen, Shrabanee A1 - Ram, Shanker A1 - Sinha, Chittaranjan A1 - Schmeißer, Dieter A1 - Mandal, Dipankar T1 - Self-Poled Transparent and Flexible UV Light-Emitting Cerium Complex–PVDF Composite: A High-Performance Nanogenerator T2 - ACS Applied Materials & Interfaces N2 - Cerium(III)-,N-dimethylformamide-bisulfate [Ce(DMF)(HSO4)3] complex is doped into poly(vinylidene fluoride) (PVDF) to induce a higher yield (99%) of the electroactive phases (β- and γ-phases) of PVDF. A remarkable enhancement of the output voltage (∼32 V) of a nano-generator (NG) based on a nonelectrically poled cerium(III) complex containing PVDF composite film is achieved by simple repeated human finger imparting, whereas neat PVDF does not show this kind of behavior. This high electrical output resembles the generation of self-poled electroactiveβ-phase in PVDF due to the electrostatic interactions between the fluoride of PVDF and the surface-active positive charge cloud of the cerium complex via H-bonding and/or bipolar interaction among the opposite poles of cerium complex and PVDF, respectively. The capacitor charging capability of the flexible NG promises its applicability as piezoelectric-based energy harvester. The cerium(III) complex doped PVDF composite film exhibit an intense photoluminescence in the UV region, which might be due to a participation of electron cloud from negative pole of bipolarized PVDF. This fact may open a new area for prospective development of high-performance energy-saving flexible solid-state UV light emitters. KW - PVDF KW - electroactive phase KW - nanogenerator KW - cerium charge transfer complex KW - piezoelectric energy harvester KW - UV-emitter Y1 - 2015 U6 - https://doi.org/10.1021/am507522r SN - 1944-8244 SN - 1944-8252 VL - 2015 IS - 7 SP - 1298 EP - 1307 ER - TY - CHAP A1 - Seime, Bernd A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Müller, Klaus A1 - Schmeißer, Dieter T1 - Buffer layer investigation of MFIS stacks with an organic ferroelectric layer T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft ; Reihe 6, Bd. 42 N2 - Ferroelectric field effect transistors are considered as future non volatile and non destructive readout memory cells. Conventional Perowskite-type ferroelectric materials are shown to work but they need expensive high temperature and high partial pressure processing steps inducing also unintentional and undefined interfacial layers.A possible low cost solution is the use of poly[vinylidene fluoride trifluoroethylene (P[VDF/TrFE]). This is a ferroelectric polymer which can be spin coated at room temperature onto silicon suited with well defined buffer layers. Using P[VDF/TrFE] we focus on metal ferroelectric insulator semi-conductor (MFIS) structures. In MFIS structure a part of the programming voltage drops over the buffering insulator. We report on attempts to minimize this fraction by optimizing the voltage divider over the buffer and the ferroelectric layers. CV measurements for different thickness of the buffer (10-235nm) and the ferroelectric layer(100nm-1μm) and for different permittivity values of the buffer layer(SiO2, Al2O3, HfO2) will be presented. This work is supported by Deutsche Forschungsgemeinschaft within priority program 1157 (DSCH 745/11-1). Y1 - 2007 UR - http://www.dpg-verhandlungen.de/year/2007/conference/regensburg/part/df/session/11/contribution/1 SN - 0420-0195 SP - S. 216 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Mandal, Dipankar A1 - Müller, Klaus A1 - Seifarth, Olaf A1 - Hoffman, Patrick A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Study of reactions at the interface P(VDF/TrFE)/Al and P(VDF/TrFE)/PEDOT:PSS T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft ; Reihe 6, Bd. 42 N2 - Due to potential use in non volatile memory application, Poly(vinylidene fluoride/trifluoroethylene) (P(VDF-TrFE)) is a great deal of interest, especially to produce organic field effect transistors (OFET). Right now it was found that Aluminum is one of the cost-effective inorganic electrode candidate. On the other hand, poly(3,4 ethylenedioxythiophene):poly(4-styrenesulfonate)(PEDOT:PSS) shows promising behavior for the application as organic electrode. In part of our investigations we have systematically studied surface interactions of organic ferroelectric thin films (P(VDF-TrFE))with inorganic (Al) and organic layers (PEDOT:PSS). By X-ray photoelectron spectroscopy (XPS) is has been found that there is a interfacial reaction with Al and the copolymer. In contrast, for electrodes, made of PEDOT: PSS, we found not such kind of behavior. In this case, we found no evidence for any surface reaction. Furthermore, we present our results concerning the orientation of permanent dipoles in the co-polymer (formed between hydrogen and fluorine atom). Here, we use Near-edge X-ray absorption fine structure (NEXAFS) analysis at the U 49/2 - PGM2 beam line of the BESSY-II Synchrotron. This work is supported by Deutsche Forschungsgemeinschaft (DFG) within priority program 1157 (DSCH 745/11-1). Y1 - 2007 UR - http://www.dpg-verhandlungen.de/year/2007/conference/regensburg/part/syoe/session/8/contribution/18 SN - 0420-0195 SP - S. 797 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Henkel, Karsten A1 - Sohal, Rakesh A1 - Torche, Mohamed A1 - Schwiertz, Carola A1 - Burkov, Yevgen A1 - Schmeißer, Dieter T1 - PrOx/AlON stacks as a high-k candidate on SiC T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft ; Reihe 6, Bd. 42 N2 - We study the chemical stability and electrical properties of Pr-oxides-SiC MIS stacks. In MISFET devices for high power applications the electric field scaling at the interface between semiconductor and insulator is determined by the ratio of their permittivity values. A high-k material can be used to optimize the performance of such devices. In previous studies we had to understand that the chemical reactivity of the PrOx/SiC interface causes a destructive interaction yielding silicate and graphite formation as well as poor electrical performance after direct deposition of PrOx onto SiC. Therefore we introduced an additional chemically inert layer and in this contribution we focus on PrOx/AlON as a suitable insulator stack. In our spectroscopic investigations we recognized a stable AlON/3C-SiC interface even for annealing steps up to 900∘C. First electrical characterizations are performed on Si substrates and we find a strong improvement in the leakage current by several orders of magnitude down to values of 10−7 A/cm2 at an EOT of 4nm and interface state densities of mean values of 5*1011/eVcm2. We also report on our ongoing electrical characterization of such stacks on SiC substrates. This work is supported by Deutsche Forschungsgemeinschaft within priority program 1157 (DSCH 745/9-2). Y1 - 2007 UR - http://www.dpg-verhandlungen.de/year/2007/conference/regensburg/part/df/session/10/contribution/8 SN - 0420-0195 SP - S. 215 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Burkov, Yevgen A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - X-ray photoemission spectroscopy of Aluminium Oxynitride on Si(001) and the rise as buffer layers T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft ; Reihe 6, Bd. 43 N2 - Praseodymium oxide (PrxOy) is one of the candidate as high-k transistor gate dielectrics, but aluminium oxynitride (AlxONy) as buffer layer is needed to prevent diffusions from the silicon into PrxOy and to hinder charge injection from the semiconductor into the insulator. The thermal stability and thickness dependence of aluminum oxynitride (AlxONy) has been investigated by synchrotron radiation photoemission spectroscopy (SR-PES). AlxONy layers were prepared by low energy ion-beam assisted deposition (LE-IBAD) at room temperature on a silicon substrate cleaned with HF-acid. Aluminium oxynitride is stable till 800∘C. From photoemission spectra we can assess that silicon oxynitride is built as first and then the growth of AlxONy follows. Resonant inelastic X-ray scattering measurements with synchrotron radiation have been performed. The combination of X-ray absorption spectroscopy (XAS) and RIXS make possible to determinate the band gap of AlxONy. Y1 - 2008 UR - http://www.dpg-verhandlungen.de/year/2008/conference/berlin/part/ds/session/23/contribution/5 SN - 0420-0195 SP - S. 243 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Henkel, Karsten A1 - Seime, Bernd A1 - Paloumpa, Ioanna A1 - Müller, Klaus A1 - Schmeißer, Dieter T1 - C(V) and C(t) measurements on MFIS structures consisting P[VDF/TrFE] as ferroelectric layer T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft ; Reihe 6, Bd. 43 N2 - Ferroelectric Field Effect Transistors (FeFETs) are considered as a candidate for future non volatile and non destructive readout memory cells. A possible low cost solution is the use of poly[vinylidene fluoride trifluoroethylene (P[VDF/TrFE]). Using P[VDF/TrFE] we focus on metal ferroelectric insulator semiconductor (MFIS) capacitor structures. In this contribution we will summarize our investigations related to capacitance measurements in dependence of applied bias (C(V)) and time (C(t)). The thickness of the ferroelectric layer as well as the thickness and the material of the buffer layer have been investigated for optimization of the write voltage. CV measurements at higher temperatures deliver decreased flatband voltage shifts within one CV loop resulting in lower memory windows. At temperatures around 100∘C the hysteresis totally vanished, pointing out the ferroelectric behavior of the system. C(t) measurements at a constant bias have been performed for retention analysis of the MFIS stack. After applying a writing pulse we could distinguish between a higher and a lower capacitance state for more than 5 days. This work is supported by Deutsche Forschungsgemeinschaft within priority program 1157 (SCHM 745/11-2). Y1 - 2008 UR - http://www.dpg-verhandlungen.de/year/2008/conference/berlin/part/sysa/session/4/contribution/7 SN - 0420-0195 SP - S. 828 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Müller, Klaus A1 - Mandal, Dipankar A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter T1 - Interface reactions of ferroelectric copolymer layers with different electrode materials T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft ; Reihe 6, Bd. 43 N2 - The ferroelectric copolymer poly(vinylidene fluoride trifluoroethylene) (P(VDF-TrFE)) is a possible material for low cost applications as organic nonvolatile memory element. We present an XPS interface investigation of the copolymer/electrode interface. Below 100nm film thickness, interface phenomena becomes important. Possible interface reactions could lead to a reduction of the ferroelectric functionality.We present a comparative study of the two interfaces Al/P(VDF-TrFE) and PEDOT:PSS/P(VDF-TrFE). The result is a clear indication of a surface reaction in between the Aluminum-electrodes. In contrast, for PEDOT:PSS the measurements shows a layer by layer formation of the interface PEDOT:PSS/PVDF without any reaction. Second, we present a study of remanent polarization of ultrathin spincoated films of the copolymer, in a thickness range from 5 to 100mn, with organic electrodes like PEDOT:PSS. The measurements are carried out by using the flatband shift of a capacitance-voltage (CV) characteristic. This shift of flatband voltage is used as value for the electric polarization of the polymer. Y1 - 2008 UR - http://www.dpg-verhandlungen.de/year/2008/conference/berlin/part/sysa/session/5/contribution/16 SN - 0420-0195 SP - S. 830 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Henkel, Karsten A1 - Torche, Mohamed A1 - Schwiertz, Carola A1 - Paloumpa, Ioanna A1 - Sohal, Rakesh A1 - Müller, Klaus A1 - Schmeißer, Dieter T1 - Inorganic and organic layers for high-k and organic memory applications T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 41 N2 - We report about organic and inorganic MIS stacks for new possibilities for high frequency and high power applications as well as for non volatile memory cell. The organic stack contains a ferroelectric polymer as the functional layer. Poly[vinylidene fluoride trifluoroethylene] (P[VDF/TrFE]) is spin coated from a solution onto oxidised silicon substrates. We report on the polarisation induced flatband voltage shifts. For the inorganic stack our attempt is to combine higk-k dielectrics with high band gap semiconductors (SiC). Praseodymium oxide layers are prepared by electron beam evaporation from Pr6O11 powder and in situ controlling of interface and volume composition (XPS). Praseodymium silicate layers were prepared either by metal evaporation onto a thin ox- ide on top of the semiconductor and following annealing steps or by a wet chemical process out of aqueous Pr(NO3)3 solutions. Using spectro-scopic characterisation we investigate the stability of the various inter-faces within the stacks as well as the reactivity of the metal electrodes on thin Pr2O3. We report the results of electrical characterisation consisting of permittivity values, leakage current and density of interface states. Y1 - 2006 UR - http://www.dpg-verhandlungen.de/year/2006/conference/dresden/part/df/session/1/contribution/4 SN - 0420-0195 SP - S. 127 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Müller, Klaus A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter T1 - P(VDF/TrFE) as ferroelectric insulation layer for organic field effect transistors T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft ; Reihe 6, Bd. 41 N2 - The ferroelectric polymer poly(vinylidene fluoride trifluoroethylene)(P(VDF-TrFE)) is used as insulating material for organic field effect tran-sistors (OFET) and metal-insulator-semiconductor (MIS)-structures. For the MIS-structures, we find the typical hysteresis in the CV charac-teristic upon increasing the voltage scan window. Based on these results, we fabricate OFET with regioregular poly(3-hexlythiophene)(P3HT) as organic semiconductor. The transistors are constructed in bottom gate architecture with thin layers of spincoated P(VDF-TrFE) as gate insulation (100nm). The drain-source current of the OFET is reversible affected by the polarized gate, which gives opportunities for organic nonvolatile memory elements. We present characteristic features like the hysteretic drain current response or the data retention. Furthermore, we present measurements with Kelvin probe force microscopy, a method which gives informations on the lateral distributions of the surface potential. Y1 - 2006 UR - http://www.dpg-verhandlungen.de/year/2006/conference/dresden/part/cpp/session/23/contribution/28 SN - 0420-0195 SP - S. 101 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Richter, Matthias A1 - Müller, Klaus A1 - Philip, Shine A1 - Paloumpa, Ioanna A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Temperature dependence of organic solar cell parameters T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft ; Reihe 6, Bd. 44 N2 - The influence of an annealing step on the parameters of bulk heterojunction organic solar cells is investigated. In order to fabricate the solar cells we use glass coated with ITO (Indiumtinoxide) as a substrate on which the active layer consisting of P3HT and PCBM is spincoated. Al-electrodes are evaporated on top of the active layer. We use PEDOT:PSS as buffer layer. Each sample is annealed at different temperatures for a short time. Between every temperature step the I-V characteristic of the cell is measured. The following parameters are derived afterwards: FF, Isc (density), Voc. Also the efficiency is estimated. The results show a maximum cell efficiency for drying at 100°C for 20sec. A further important step for preparation is the drying procedure of the PEDOT:PSS layer. Here an improvement of about 50% in cell efficiency is measured after drying at 50°C for 5 days under inert gas atmosphere. Y1 - 2009 UR - http://www.dpg-verhandlungen.de/year/2009/conference/dresden/part/syop/session/4/contribution/2 SN - 0420-0195 SP - S. 671 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Hoffmannbeck, David A1 - Richter, Matthias A1 - Städter, Matthias A1 - Paloumpa, Ioanna A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Spectroscopic and microscopic characterization of potential catalysts for the hydrogenation of CO2 T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 46 N2 - The reduction of CO2 emissions is a general demand of the society in order to avoid irreversible climate changes. We are investigating potential catalysts for the hydrogenation of CO2 in particular for its application in the so called oxyfuel combustion process. In order to understand the catalytic behavior of the investigated materials we use the techniques X-Ray Photoemission (XPS) and -absorption (XAS) Spectroscopy as well as X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The prospective of our work is to figure out the electronic and structural properties of the material and to optimize proper catalysts or design new ones for best catalytic activity. Beside the spectro-microscopic investigations the catalysts are tested under Sabatier reaction conditions in terms of activity, stability and sensitivity against poisoning. In our preliminary work we constructed a Sabatier reactor system with analytical parts based on infrared absorption and mass spectroscopy modules. First spectroscopic and catalytic results achieved on a commercially available Ru/Al2O3 catalyst will be presented. Y1 - 2011 UR - http://www.dpg-verhandlungen.de/year/2011/conference/dresden/part/o/session/60/contribution/123 SN - 0420-0195 SP - S. 483 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Mbua, Roy A1 - Müller, Klaus A1 - Richter, Matthias A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter A1 - Kramm, Ulricke T1 - Investigation of new Catalysts for PEM Fuel Cells T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 46 N2 - Increasing green house emissions amplify global warming concerns worldwide. Fuel cells, based on polymer electrolyte membranes (PEM) are part of the solution to this issue. We aim at developing and testing new catalysts for fuel cells. Platinum catalysts perform best in PEM fuel cells to date but they are very expensive. For fuel cells to be perfectly applicable and economically affordable, an alternative catalyst with similar or even greater efficiency should be developed. Metal phthalocyanines are known to be good oxygen reduction catalysts and are associated with high electron transfer properties. We investigated Cobalt Phthalocyanine in its pure state mixed with Carbon Black (CoPc:Carbon Black=1:9) untreated and also after a treatment in N2 at several temperatures, up to 1000°C for 30 minutes. Results of XPS and EDX analyses reveal that the treatment at higher temperatures causes a rearrangement in the chemical states of Co, N and C atoms. Furthermore, results of cycling voltammetry (CV) analysis reveal that CoPc treated in N2 at 800°C exhibited a higher current density, in conclusion, a higher catalytic activity than the untreated CoPc. Y1 - 2011 UR - http://www.dpg-verhandlungen.de/year/2011/conference/dresden/part/o/session/60/contribution/119 SN - 0420-0195 SP - S. 483 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Henkel, Karsten A1 - Das, Chittaranjan A1 - Sowinska, Małgorzata A1 - Tallarida, Massimo A1 - Schmeißer, Dieter A1 - Gargouri, Hassan A1 - Kärkkänen, Irina A1 - Schneidewind, Jessica A1 - Gruska, Bernd A1 - Arens, Michael ED - Glück, B. K. ED - Schmidt, S. ED - Stein, E. ED - Raschke, Jörg-Uwe ED - Richter, H. T1 - Charakterisierung von TiO2-ALD-Schichten und deren Nutzung für die Passivierung von Si-Photokathoden T2 - Tagungsband Photovoltaik-Meeting: Anwendungen-Qualität-Perspektiven, Senftenberg, 15.04.2015 N2 - Wir berichten zunächst über den Einfluss der Methode der Atomlagenabscheidung auf die TiO2-Schichteigenschaften. Insbesondere wird der Zusammenhang zwischen Ti3+- sowie Interbandzuständen mit elektrischen Kennlinien und deren Einfluss auf funktionale Schichteigenschaften diskutiert. Anschließend werden Mikrostrukturierung, Grenzflächen-Engineering und konforme Abscheidung einer TiO2-ALD-Schutzschicht effektiv zur Performance-Steigerung von p-Si-Photokathoden angewendet. KW - TiO2 KW - Korrosion KW - Atomlagenabscheidung KW - Silizium KW - Photokathoden KW - Linear Scan Voltametry KW - Photoelektronenspektroskopie Y1 - 2015 SP - 3 EP - 8 PB - BTU Cottbus-Senftenberg CY - Senftenberg ER - TY - GEN A1 - Tamang, Abiral A1 - Ghosh, Sujoy Kumar A1 - Garain, Samiran A1 - Alam, Md. Mehebub A1 - Haeberle, Jörg A1 - Henkel, Karsten A1 - Schmeißer, Dieter A1 - Mandal, Dipankar T1 - DNA-Assisted β‑phase Nucleation and Alignment of Molecular Dipoles in PVDF Film: A Realization of Self-Poled Bioinspired Flexible Polymer Nanogenerator for Portable Electronic Devices T2 - ACS Applied Materials & Interfaces N2 - A flexible nanogenerator (NG) is fabricated with a poly(vinylidene fluoride) (PVDF)film, where deoxyribonu-cleic acid (DNA) is the agent for the electroactive β-phase nucleation. Denatured DNA is co-operating to align the molecular−CH2/−CF2 dipoles of PVDF causing piezo- electricity without electrical poling. The NG is capable of harvesting energy from a variety of easily accessible mechanical stress such as human touch, machine vibration, football juggling, and walking. The NG exhibits high piezoelectric energy conversion efficiency facilitating the instant turn-on of several green or blue light-emitting diodes. The generated energy can be used to charge capacitors providing a wide scope for the design of self-powered portable devices. KW - PVDF KW - β-phase KW - DNA KW - self-poling KW - piezoelectric flexible nanogenerator Y1 - 2015 U6 - https://doi.org/10.1021/acsami.5b04161 SN - 1944-8244 SN - 1944-8252 IS - 7 SP - 16143 EP - 16147 ER - TY - GEN A1 - Sowińska, Małgorzata A1 - Henkel, Karsten A1 - Schmeißer, Dieter A1 - Kärkkänen, Irina A1 - Schneidewind, Jessica A1 - Naumann, Franziska A1 - Gruska, Bernd A1 - Gargouri, Hassan T1 - Plasma-enhanced atomic layer deposition of titanium oxynitrides films: A comparative spectroscopic and electrical study T2 - Journal of Vacuum Science and Technology A N2 - The process parameters’ impact of the plasma-enhanced atomic layer deposition (PE-ALD) method on the oxygen to nitrogen (O/N) ratio in titanium oxynitride (TiOxNy) films was studied. Titanium(IV)isopropoxide in combination with NH3 plasma and tetrakis(dimethylamino) titanium by applying N2 plasma processes were investigated. Samples were characterized by the in situ spectroscopic ellipsometry, x-ray photoelectron spectroscopy, and electrical characterization (current–voltage: I-V and capacitance–voltage: C-V) methods. The O/N ratio in the TiOxNy films is found to be very sensitive for their electric properties such as conductivity, dielectric breakdown, and permittivity. Our results indicate that these PE-ALD film properties can be tuned, via the O/N ratio, by the selection of the process parameters and precursor/coreactant combination. KW - plasma enhanced atomic layer deposition KW - titanium oxynitride KW - X-ray photoelectron spectroscopy KW - ellipsometry KW - current-voltage KW - capacitance-voltage Y1 - 2016 U6 - https://doi.org/10.1116/1.4936227 SN - 0734-2101 SN - 1520-8559 IS - 34 SP - 01A127-1 EP - 01A127-9 ER - TY - CHAP A1 - Tallarida, Massimo A1 - Henkel, Karsten A1 - Gargouri, Hassan A1 - Haeberle, Jörg A1 - Gruska, Bernd A1 - Arens, Matthias A1 - Schmeißer, Dieter T1 - New opportunities with Plasma enhanced atomic layer deposition (PE-ALD) of oxides T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - Thermal Atomic layer deposition (T-ALD) of oxides is obtained by the pulsed alternation of a metal precursor and an oxygen source, typically H2O or O3, and the reactions leading to ALD are thermally activated. With plasma enhanced ALD (PE-ALD), instead, the oxygen source is represented by an oxygen-containing plasma. The higher reactivity of the plasma-generated species extend the capabilities of ALD: improved film quality and increased flexibility in process conditions, such as growth at low temperature, are typical advantages of PE-ALD over T-ALD. We report on results on the preparation of thin (<100 nm) aluminum oxide (Al2O3) films on silicon substrates using T-ALD and PE-ALD in the SENTECH SI ALD LL system. Films were deposited in the temperature range between room temperature (RT) and 200∘C. We characterized the films with spectroscopic ellipsometry (thickness, refractive index, growth rate) over 4" wafers and with X-ray photoelectron spectroscopy. All films resulted in a high degree of homogeneity, independent of the deposition temperature. Investigations with capacitance-voltage and conductance-voltage measurements showed a very low interface states density for the PE-ALD films. KW - Atomic layer deposition KW - Plasma enhanced atomic layer deposition KW - X-ray photoelectron spectroscopy KW - spectroscopic ellipsometry KW - dielectric properties KW - Al2O3 Y1 - 2014 UR - http://www.dpg-verhandlungen.de/year/2014/conference/dresden/part/ds/session/49/contribution/3?lang=en SN - 0420-0195 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Mandal, Dipankar A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - A polymer nanogenerator based on silver nanoparticles doped electrospun P(VDF-HFP) nanofibers T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - The rising energy demand within the increasing mobility of human society has driven the development of new alternative power sources for portable devices with ultra-low electric power consumption. Based on its piezoelectric properties poly-vinylidene fluoride (PVDF) is a good candidate for mechanical energy harvesting for such devices. Moreover the copolymer poly(vinylidene fluoride-hexafluoropropylene) [P(VDF-HFP)] offers better film flexibility and cost-effectiveness than pure PVDF. We report on a polymer nanogenerator (PNG) based on electrospun P(VDF-HFP) nanofibers doped with silver nanoparticles (Ag-NPs). The electrospun fibers were characterized by FTIR, XPS, SEM and pressure imparting probe. It has been found that the yield of the piezoelectric phase is increased by the addition of Ag-NPs due to an interaction between surface charges of Ag-NPs and the molecular dipoles. Furthermore, defects in the P(VDF-HFP) electrospun fibers are removed. Accordingly, a significant enhancement in the output power of the PNG was found. Similar trends were also observed with Pd-NPs. KW - nanogenerator KW - PVDF KW - nanoparticles Y1 - 2015 UR - http://www.dpg-verhandlungen.de/year/2015/conference/berlin/part/ds/session/36/contribution/34?lang=en SN - 0420-0195 SP - S. 208 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - GEN A1 - Sowinska, Małgorzata A1 - Brizzi, Simone A1 - Das, Chittaranjan A1 - Kärkkänen, Irina A1 - Schneidewind, Jessica A1 - Naumann, Franziska A1 - Gargouri, Hassan A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Analysis of nitrogen species in titanium oxynitride ALD films T2 - Applied Surface Science N2 - Titanium oxynitride films are prepared by plasma enhanced atomic layer deposition method using two different precursors and nitrogen sources. Synchrotron radiation-based X-ray photoelectron spectroscopy and X-ray absorption spectroscopy are used to characterize the nitrogen species incorporated within these films depending on the deposition parameters. It is found that nitrogen atoms in these films are differently bonded. In particular, it can be distinguished between Ti-ON and Ti-N bonding configurations and molecular nitrogen species caused by precursor fragments. KW - titanium oxynitride KW - X-ray photoelectron spectroscopy KW - X-ray absorption spectroscopy KW - ALD process parameters Y1 - 2016 U6 - https://doi.org/10.1016/j.apsusc.2016.02.096 SN - 0169-4332 SN - 1873-5584 VL - 381 SP - 42 EP - 47 ER - TY - GEN A1 - Das, Chittaranjan A1 - Kot, Małgorzata A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Engineering of Sub-Nanometer SiOₓ Thickness in Si Photocathodes for Optimized Open Circuit Potential T2 - ChemSusChem N2 - Silicon is one of the most promising materials to be used for tandem-cell water-splitting devices. However, the electrochemical instability of bare Si makes it difficult to be used for stable devices. Besides that, the photovoltage loss in Si, caused by several factors (e.g., metal oxide protection layer and/or SiO₂/Si or catalyst/Si interface), limits its use in these devices. In this work, we present that an optimized open circuit potential (OCP) of Si can be obtained by controlling the SiOₓ thickness in sub-nanometer range. It can be done by means of a simple and cost-effective way using the combination of a wet chemical etching and the low temperature atomic layer deposition (ALD) of TiO₂. We have found that a certain thickness of the native SiOₓ is necessary to prevent further oxidation of the Si photocathode during the ALD growth of TiO₂. Moreover, covering the Si photocathode with an ALD TiO₂ layer enhances its stability. KW - atomic layer deposition KW - open circuit potential KW - Si photocathodes KW - silica KW - stability Y1 - 2016 U6 - https://doi.org/10.1002/cssc.201600777 SN - 1864-5631 SN - 1864-564X VL - 9 IS - 17 SP - 2332 EP - 2336 ER - TY - GEN A1 - Garain, Samiran A1 - Barman, Koushik A1 - Sinha, Tridib Kumar A1 - Jasimuddin, Sk A1 - Haeberle, Jörg A1 - Henkel, Karsten A1 - Schmeißer, Dieter A1 - Mandal, Dipankar T1 - Cerium(III) Complex Modified Gold Electrode: An Efficient Electrocatalyst for the Oxygen Evolution Reaction T2 - ACS Applied Materials and Interfaces N2 - Exploring efficient and inexpensive electrocatalysts for the oxidation of water is of great importance for various electrochemical energy storage and conversion technologies. In the present study, a new water-soluble [Ce III(DMF) (HSO4)3] complex was synthesized and characterized by UV−vis, photoluminescence, and high-resolution X-ray photoelectron spectroscopy techniques. Owing to classic 5d →4f transitions, an intense photoluminescence in the UV region was observed from the water-soluble [CeIII(DMF (HSO4)3] complex. A stacking electrode was designed where self-assembled L-cysteine monolayer modified gold was immobilized with the synthesized cerium complex and was characterized by scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltam-metry. The resulting electrode, i.e., [CeIII(DMF)(HSO4)3]−L-cysteine-Au stacks shows high electrocatalytic water oxidation behavior at an overpotential of η ≈0.34 V under neutral pH conditions. We also demonstrated a way where the overpotential is possible to decrease upon irradiation of UV light. KW - water oxidation KW - electrocatalyst KW - photoelectrocatalyst KW - photoluminescence KW - Ce(III)-complex KW - L-cysteine KW - gold electrode Y1 - 2016 U6 - https://doi.org/10.1021/acsami.6b05236 SN - 1944-8244 SN - 1944-8252 VL - 8 IS - 33 SP - 21294 EP - 21301 ER - TY - CHAP A1 - Rouissi, Zied A1 - Henkel, Karsten A1 - Tallarida, Massimo A1 - Schmeißer, Dieter T1 - ALD growth of Al2O3 on Stepped Surface of HOPG and Ag-HOPG T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - Atomic Layer Deposition (ALD) is an excellent deposition technique to grow thin film with high homogeneity coverage on ideal surfaces. Here we are interested in the growth properties on non-ideal (stepped, inert) surfaces. Using STM we studied the growth of Al2O3 by ALD on stepped surface of HOPG and silver covered HOPG (Ag-HOPG). The HOPG sample was cleaved to and then cleaned by N2 in vacuum. We obtain regular steps with terrace widths of 50nm - 500nm. Ag was deposited by thermal deposition on the HOPG. The Al2O3 growth at RT was studies after the first, third, and fifth cycle. Silver evaporation leads to step decoration with island of 1nm-7nm. On the terraces we find the formation of 2D domain of Ag chains. The features caused by the individual ALD cycles of Al2O3 depend on the terrace widths of the HOPG substrate. For small terraces (<100nm) we obtain a growth of 2D domains ( 20nm-25nm) on the edge steps and in the middle of the terrace. For large terraces (>100nm) we find agglomeration of the precursors on individual nucleation sites. Here 3D islands are formed with a height of up to 5nm in the fifth ALD cycle. KW - atomic layer deposition KW - Scanning tunneling microscopy (STM) KW - Al2O3 KW - HOPG Y1 - 2016 UR - http://www.dpg-verhandlungen.de/year/2016/conference/regensburg/part/o/session/89/contribution/12?lang=en SP - S. 419 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Sohal, Rakesh A1 - Henkel, Karsten A1 - Müller, Klaus A1 - Schmeißer, Dieter T1 - Growth and Characterization of 3C-SiC thin films on Si substrates T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - This work reports on the growth and characterization of cubic silicon carbide thin films. A cold wall low pressure chemical vapour deposition (LPCVD) system has been used to grow the cubic silicon carbide. The two step method, carbonization and subsequent growth, has been used to grow good quality 3C-SiC thin films. The composition and structure of deposited thin films have been analysed by Fourier Transform Infrared Spectroscopy (FTIR), XPS and X-Ray Diffractometry (XRD). The structural quality of the films has been optimized as a function of substrate temperature during carbonization and growth. X-rays diffraction measurements shows that the grown layers are highly oriented crystalline cubic silicon carbide. KW - low pressure chemical vapor deposition (LPCVD) KW - 3C-SiC KW - X-ray photoelectron spectroscopy (XPS) KW - Fourier Transform Infrared Spectroscopy (FTIR) KW - X-Ray diffraction Y1 - 2005 UR - http://www.dpg-verhandlungen.de/year/2005/conference/berlin/part/hl/session/58/contribution/50?lan=en PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Torche, Mohamed A1 - Müller, Klaus A1 - Henkel, Karsten A1 - Lupina, Grzegorz A1 - Goryako, Andrey A1 - Wollweber, Jürgen A1 - Schmeißer, Dieter T1 - Investigations of 3C-SiC growth on Si (001) T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - Carbide was grown on Si (001) - substrates with supply of C2H2. Investigation of the interface Si/SiC (buffer layer) is essential for optimized preparation conditions, leading to a high quality of the growing SiC crystal. In addition to the lattice mismatch of 20 per cent between Si and SiC, which causes defects like dislocations or stacking faults, the chemical homogeneity of this layer is important. XPS was used to characterize the first state of SiC crystal growth on the Si substrate. Carbonizing with C2H2 leads to surface reactions which build up the buffer layer. By using electron spectroscopy, it was possible to characterize the SiC/Si (001) buffer layer, depending on the following reaction parameters: Tsubstrate , PC2H2 , PH2 , the ratio of pressures and the reaction time. The measurements were performed in terms of the content of carbide, oxide and roughness/etching-efficiency (Profilometer) for the reaction parameters above. We found, that the most critical parameter is the temperature of the substrate (Tsubstrate). KW - 3C-SiC KW - chemical vapor deposition (CVD) KW - X-ray photoelectron spectroscopy (XPS) Y1 - 2004 UR - http://www.dpg-verhandlungen.de/year/2004/conference/regensburg/part/hl/session/44/contribution/42?lang=de PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Henkel, Karsten A1 - Paloumpa, Ioanna A1 - Müller, Klaus A1 - Schmeißer, Dieter T1 - P(VDF/TrFE) as a ferroelectric dielectric for Organic Field effect Transistors in MFIS structure T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - MFIS structures consisting of metal, ferroelectric poly[vinylidene fluoride trifluoroethylene](P[VDF/TrFE]), insulator, semiconductor (Si) are fabricated and the influence of the polarization of the P(VDF/TrFE) on the CV characteristics of these structures is investigated. We find a characteristic ferroelectric hysteresis in the CV curves upon increasing the voltage scan window (e.g.-U...U,U=6...30V, |UP(VDF/TrFE)|≤15V, dP(VDF/TrFE)=300 nm). A writing process with adequate electric fields causes large shifts in the flatband voltage ( Δ UFB>4V for the quoted example before) which are stable over days. We report on our investigations which focus on the switching behavior by varying the parameters like polymer thickness, writing field strength and time, long time stability, reversing voltage and insulating material (SiO2, PMMA (Polymethylmetacrylate)). This material combination is favorable for transfer into our full organic concept of field effect transistors for application as a nondestructive readout memory (NDRO) cell. KW - P(VDF/TrFE) KW - Organic ferroelectric field effect transistor KW - capacitance voltage measurements Y1 - 2005 UR - http://www.dpg-verhandlungen.de/year/2005/conference/berlin/part/syoo/session/6/contribution/39?lan=en PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Müller, Klaus A1 - Paloumpa, Ioanna A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Organic Field Effect Transistors with polymer high-k dielectric insulator T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - Organic field effect transistors consisting of the copolymer poly(vinylidene fluoridetrifluoroethylene) (P(VDF-TrFE)) and P3HT (poly(3-hexlythiophene)) as active layer have been fabricated. The influence of P(VDF-TrFE) on the transconductance of organic field effect transistors was investigated and enhanced gate effects are observed compared to similar transistors with PMMA (Polymethylmetacrylate) as gate dielectric. Due to the high dielectric constant of P(VDF-TrFE) (DK=12) an operation voltage smaller than for a conventional organic dielectric like PMMA (DK=3.3) was observed. The thickness of the spincoated dielectric layers is in the range of 2microns and in consequence, no significant hysteresis was found, a prerequisite for transistor operation. KW - organic field effect transistor KW - P(VDF/TrFE) KW - high-k organic Y1 - 2005 UR - http://www.dpg-verhandlungen.de/year/2005/conference/berlin/part/syoo/session/6/contribution/30?lan=en PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - GEN A1 - Ghosh, Sujoy Kumar A1 - Biswas, Anirban A1 - Sen, Shrabanee A1 - Das, Chittaranjan A1 - Henkel, Karsten A1 - Schmeißer, Dieter A1 - Mandal, Dipankar T1 - Yb3+ Assisted Self-Polarized PVDF Based Ferroelectretic Nanogenerator: A Facile Strategy of Highly Efficient Mechanical Energy Harvester Fabrication T2 - Nano Energy N2 - Ytterbium (Yb3+) assisted porous poly(vinylidene fluoride) (PVDF) composite film comprising flexible ferroelectretic nanogenerator (FTNG) is highlighted where traditional poling treatment is completely avoided. The piezoelectric output of FTNG is realized by the co-operative activity of self-polarized -CH2/-CF2 dipoles with porous electret-like structure in the composite film. Owing to extraordinary ferroelectric and dielectric properties, FTNG is acting as a highly efficient mechanical energy harvester. It is capable to capture several forms of abundant mechanical energy arising from humanfinger movements, machine vibrations and sound waves. As a proof of concept, under compressive deformation, FTNG is enable to instantly powers up several consumer electronics and thus provides a promising strategy for achieving self-powered electronic devices. KW - PVDF KW - Yb 3+ KW - Porous ferroelectret material KW - Self-polarization KW - Ferroelectretic nanogenerator KW - Mechanical energy harvester KW - Self-powered electronics Y1 - 2016 U6 - https://doi.org/10.1016/j.nanoen.2016.10.042 SN - 2211-2855 VL - 2016 IS - 30 SP - 621 EP - 629 ER - TY - GEN A1 - Henkel, Karsten A1 - Kot, Małgorzata A1 - Schmeißer, Dieter T1 - Localized defect states and charge trapping in atomic layer deposited-Al₂O₃ films T2 - Journal of Vacuum Science and Technology, A : Vacuum, Surfaces, and Films N2 - In this study, the authors compared different Al₂O₃ films grown by atomic layer deposition (ALD) with the same aluminum precursor but on different substrates. The authors employed different process parameters such as thermal-ALD and plasma-enhanced-ALD using different substrate temperatures ranging from 280 °C down to room temperature. They characterized these films by resonant photoelectron spectroscopy and by electrical measurements. They established that generally the ALD-Al₂O₃ films show characteristic features of bulk Al₂O₃. For all films investigated, the authors found intrinsic defect states within the electronic band gap and identified excitonic, polaronic, and charge-transfer defect states. The authors gave an atomistic model to explain these intrinsic defects and found that their relative abundance is subject of the choice of ALD parameters and of the substrate used. They were able to relate the spectroscopic assigned in-gap defect states with the electronic charges as determined in our electrical measurements. KW - defect states KW - resonant photoelectron spectroscopy (resPES) KW - Al₂O₃ KW - atomic layer deposition (ALD) KW - excitons KW - polarons Y1 - 2017 U6 - https://doi.org/10.1116/1.4971991 SN - 0734-2101 SN - 1520-8559 VL - 35 IS - 1 SP - 01B125-1 EP - 01B125-18 ER - TY - GEN A1 - Kot, Małgorzata A1 - Das, Chittaranjan A1 - Wang, Zhiping A1 - Henkel, Karsten A1 - Rouissi, Zied A1 - Wojciechowski, Konrad A1 - Snaith, Henry J. A1 - Schmeißer, Dieter T1 - Room-Temperature Atomic Layer Deposition of Al₂O₃: Impact on Efficiency, Stability and Surface Properties in Perovskite Solar Cells T2 - ChemSusChem N2 - In this work, solar cells with a freshly made CH₃NH₃PbI₃ perovskite film showed a power conversion efficiency (PCE) of 15.4 % whereas the one with 50 days aged perovskite film only 6.1 %. However, when the aged perovskite was covered with a layer of Al₂O₃ deposited by atomic layer deposition (ALD) at room temperature (RT), the PCE value was clearly enhanced. X-ray photoelectron spectroscopy study showed that the ALD precursors are chemically active only at the perovskite surface and passivate it. Moreover, the RT-ALD-Al2O3-covered perovskite films showed enhanced ambient air stability. KW - Al₂O₃ KW - atomic layer deposition (ALD) KW - perovskite KW - solar cells KW - X-ray photoelectron spectroscopy (XPS) Y1 - 2016 U6 - https://doi.org/10.1002/cssc.201601186 SN - 1864-5631 SN - 1864-564X VL - 9 IS - 24 SP - 3401 EP - 3406 ER - TY - GEN A1 - Henkel, Karsten A1 - Das, Chittaranjan A1 - Kot, Małgorzata A1 - Schmeißer, Dieter A1 - Naumann, Franziska A1 - Kärkkänen, Irina A1 - Gargouri, Hassan T1 - In-gap states in titanium dioxide and oxynitride atomic layer deposited films T2 - Journal of Vacuum Science and Technology: A N2 - Valence band (VB) spectra of titanium dioxide (TiO2) and oxynitride (TiOxNy) films prepared by different atomic layer deposition (ALD) processes are compared and related to electrical characterization [current–voltage (JV) and capacitance–voltage (CV)] results. By increasing the nitrogen amount in the TiO2 film, band-gap narrowing is observed. The band-gap decrease is related to the contribution of the nitrogen density of states, which induces defects within the band-gap and thus reduces its optical band-gap. In-gap states are found in the VB spectra at 1 eV below the Fermi energy in all investigated ALD samples, i.e., in TiO2 as well as in TiOxNy films. An exponential correlation between leakage current density and in-gap state intensity is derived by the combination of JV measurements and VB spectra, whereas the in-gap states seem to have no influence on hysteresis and fixed oxide charges found in the CV data. It is argued that the in-gap states in TiO2 and TiOxNy have an excitonic or polaronic origin. Both, band-gap narrowing and in-gap state intensity can be tuned by the ALD process selection and the variation of its parameters. KW - Titanium dioxide (TiO2) KW - Titanium oxynitrdie (TiON) KW - valence band spectra KW - in-gap states KW - band-gap narrowing KW - electrical characterization Y1 - 2017 U6 - https://doi.org/10.1116/1.4972247 SN - 0734-2101 SN - 1520-8559 VL - 35 IS - 1 SP - 01B135-1 EP - 01B135-8 ER - TY - CHAP A1 - Garain, Samiran A1 - Adhikary, Prakriti A1 - Mandal, Dipankar A1 - Sen, Shrabanee A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Electro-active β-Phase Formation in Poly(vinylidene fluoride) Films by Hydrated Rare earth Metal Salt T2 - Proceeding of the International Conference on Nanotechnology 2013 (ICNT 2013) N2 - Polyvinylidene fluoride (PVDF) is a typical fluoro-polymer with complicated polymorphisms due to the semi-crystalline nature. Generally, four crystalline phases, α, β, γ and δ may exist in PVDF crystals. The nonpolar α- and δ-phase has a monoclinic lattice with trans-gauche conformation (TGTG⁄), which is thermodynamically most stable for PVDF. The polar β phase with all-trans (TTTT) planar zigzag conformation is attractive for its piezo-, pyro-, and ferroelectric properties. The polar β-Phase and also semi-polar γ-phase (TTTGTTTG⁄) have obtained wide device applications such as acoustic transducers, piezoelectric sensors, energy harvesting generators, pyroelectric sensors, non-volatile memories and energy storage capacitors. In this work, we explore the possibility to nucleate β-phase in PVDF hydrated salt composite films by addition of the hydrated Rare earth metal salt, (NH4)4 Ce (SO4)4, 2H2O) for the piezo- ferro and high dielectric based device applications. It has been found that the water molecules in (NH4)4 Ce (SO4)4, 2H2O could form hydrogen bonds with PVDF during the crystallization process and the hydrogen bonds promoted the electro-active crystalline β- phase in PVDF with all -trans conformations. In addition, the DMF (solvent used for films preparation) can also assist the rare-earth based nanoparticle preparation, as a result the electrostatic interaction of the surface charge of the nanoparticles and molecular dipoles in PVDF can resist the electroactive β- phase in PVDF. KW - PVDF KW - β-Phase KW - piezoelectric Y1 - 2013 SN - 978-81-927756-0-9 SP - S. 127 PB - Institute of Technology, Haldia, WB, India CY - Haldia ER - TY - CHAP A1 - Schmeißer, Dieter A1 - Müller, Sebastian A1 - Henkel, Karsten A1 - Müller, Klaus A1 - Wehner, Stefan T1 - In-situ analysis of moving reaction fronts for the bistable CO oxidation reaction on noble metal catalyst T2 - Extended Abstracts Book of First International Conference on Materials for Energy N2 - 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. KW - CO oxidation KW - Ir KW - Pd KW - photo electron emission microscopy (PEEM) Y1 - 2010 SN - 978-3-89746-117-8 SP - S. 932 PB - Dechema e.V. CY - Frankfurt ER - TY - CHAP A1 - Henkel, Karsten A1 - Kot, Małgorzata A1 - Schmeißer, Dieter T1 - Localized defect states and charge trapping in Al₂O₃ films prepared by atomic layer deposition T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - The evaluation of the electronic structure and intrinsic defect mechanisms in Al₂O₃ thin films is essential for their effective use in applications with desired functionality such as surface passivation schemes for solar cells [1]. We present a comparative study of different Al₂O₃ films grown by atomic layer deposition (ALD) [2]. The layers were deposited on different substrates using the same aluminum precursor (TMA, trimethylalumium) and employing different process parameters (thermal-ALD, plasma-enhanced-ALD, substrate temperature). These films were characterized by resonant photoelectron spectroscopy and by electrical measurements (capacitance-voltage). For all films investigated intrinsic defect states within the electronic band gap were observed including excitonic, polaronic, and charge-transfer defect states, where their relative abundance is subject of the choice of ALD parameters and of the used substrate. The spectroscopic assigned in-gap defect states are related with electronic charges as determined in the electrical measurements. [1] G. Dingemans and W.M.M. Kessels, J. Vac. Sci. Technol. A 30, 040802 (2012). [2] K. Henkel, M. Kot, D. Schmeißer, J. Vac. Sci. Technol. A 35, (2017), accepted. KW - defect states KW - Al₂O₃ KW - resonant photoelectron spectroscopy KW - X-Ray absorption spectroscopy KW - capacitance-voltage measurements Y1 - 2017 UR - http://www.dpg-verhandlungen.de/year/2017/conference/dresden/part/ds/session/32/contribution/4 SN - 0420-0195 SP - S. 205 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - GEN A1 - Das, Chittaranjan A1 - Kot, Małgorzata A1 - Rouissi, Zied A1 - Kędzierski, Kamil A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Selective Deposition of an ultrathin Pt Layer on a Au-Nanoisland-Modified Si Photocathode for Hydrogen Generation T2 - ACS Omega N2 - Platinum, being the most efficient and stable catalyst, is used in photoelectrochemical (PEC) devices. However, a minimal amount of Pt with maximum catalytic activity is required to be used to minimize the cost of production. In this work, we use an environmentally friendly, ost-effective, and less Pt-consuming method to prepare PEC devices for the hydrogen evolution reaction (HER). The Pt monolayer catalyst is selectively deposited on a Au-nanoisland-supported boron-doped p-type Si (100) photocathode. The PEC device based on the Si photocathode with an ultralow loading of the Pt catalyst exhibits a comparable performance for the HER to that of devices with a thick Pt layer. In addition, we demonstrate that by using a thin TiO2 layer deposited by atomic layer deposition photo-oxidation of the Si photocathode can be blocked resulting in a stable PEC performance. KW - water splitting KW - hydrogen evolution reaction (HER) KW - Si photocathode KW - gold nanoislands KW - nanostructured platinum Y1 - 2017 U6 - https://doi.org/10.1021/acsomega.6b00374 SN - 2470-1343 VL - 2 IS - 4 SP - 1360 EP - 1366 ER - TY - GEN A1 - Kot, Małgorzata A1 - Henkel, Karsten A1 - Das, Chittaranjan A1 - Brizzi, Simone A1 - Kärkkänen, Irina A1 - Schneidewind, Jessica A1 - Naumann, Franziska A1 - Gargouri, Hassan A1 - Schmeißer, Dieter T1 - Analysis of titanium species in titanium oxynitride films prepared by plasma enhanced atomic layer deposition T2 - Surface and Coatings Technology N2 - A comparative study of thin titanium oxynitride (TiOxNy) films prepared by plasma enhanced atomic layer deposition using tetrakis(dimethylamino)titanium (TDMAT) and N2 plasma as well as titanium(IV)isopropoxide and NH3 plasma is reported. The comparison is based on the combination of Ti2p core level and valence band spectroscopy and current-voltage measurements. The TDMAT/N2 process delivers generally higher fractions of TiN and TiON within the Ti2p spectra of the films and stronger photoemissions within the bandgap as resolved in detail by high energy resolution synchrotron-based spectroscopy. In particular, it is shown that higher TiN contributions and in-gap emission intensities correlate strongly with increased leakage currents within the films and might be modified by the process parameters and precursor selection. KW - Titanium oxynitride KW - Plasma enhanced atomic layer deposition (PEALD) KW - ALD process parameters KW - Ti-N contributions KW - In-gap defect states KW - Leakage current Y1 - 2017 U6 - https://doi.org/10.1016/j.surfcoat.2016.11.094 SN - 0257-8972 SN - 1879-3347 VL - 324 SP - 586 EP - 593 ER - TY - GEN A1 - Biswas, Anirban A1 - Henkel, Karsten A1 - Schmeißer, Dieter A1 - Mandal, Dipankar T1 - Comparison of the thermal stability of the α, β and γ phases in poly(vinylidene fluoride) based on in situ thermal Fourier transform infrared spectroscopy T2 - Phase Transitions N2 - The electroactive β phase of poly(vinylidenefluoride) (PVDF) is induced due to the aging time of PVDF solutions. The feasibility of the combination of the three crystalline polymorphs (α, β and γ) is demonstrated where their relative proportion within the PVDF film can be tailored by the simple monitoring of the preparation conditions. To identify all these phases, Fourier transform infrared (FT-IR) spectroscopy is carried out and it is spotlighted that the vibrational bands at 510 and 841 cm-1 are not sufficient to state the formation of the β phase. The main aim of this work is devoted to develop a better understanding on the thermal stability of these several phases of PVDF, which has a longstanding ambiguity persisting in this area. It has been found that the in situ thermal FT-IR spectroscopy is one of the best alternatives to understand this important issue. It is ascertained that the β phase is the least thermally stable phase among α, β and γ phases, whereas the γ phase is the most thermally stable phase. KW - PVDF KW - thermal stability KW - β-phase KW - infrared spectroscopy KW - in situ thermal FT-IR study Y1 - 2017 U6 - https://doi.org/10.1080/01411594.2017.1337902 SN - 0141-1594 SN - 1029-0338 VL - 90 IS - 12 SP - 1205 EP - 1213 ER - TY - GEN A1 - Kot, Małgorzata A1 - Das, Chittaranjan A1 - Henkel, Karsten A1 - Wojciechowski, Konrad A1 - Snaith, Henry J. A1 - Schmeißer, Dieter T1 - Room temperature atomic layer deposited Al₂O₃ on CH₃NH₃PbI₃ characterized by synchrotron-based X-ray photoelectron spectroscopy T2 - Nuclear Instruments and Methods in Physics Research B N2 - An ultrathin Al₂O₃ film deposited on methylammonium lead triiodide (CH₃NH₃PbI₃) perovskite has the capability to suppress the carrier recombination process and improve the perovskite solar cells efficiency and stability. However, annealing at temperatures higher than 85°C degrades the CH₃NH₃PbI₃ perovskite film. The X-ray photoelectron spectroscopy study performed in this work indicates that it is possible to grow Al₂O₃ by atomic layer deposition on the perovskite at room temperature, however, besides pure Al₂O₃ some OH groups are found and the creation of lead and iodine oxides at the Al₂O₃/CH₃NH₃PbI₃ interface takes place. KW - Synchrotron-based X-ray photoelectron spectroscopy KW - Perovskite solar cells KW - Atomic layer deposition KW - Al₂O₃ Y1 - 2017 U6 - https://doi.org/10.1016/j.nimb.2017.01.082 SN - 0168-583X SN - 1872-9584 VL - 411 SP - 49 EP - 52 ER - TY - GEN A1 - Müller, Klaus A1 - Bär, Werner A1 - Henkel, Karsten A1 - Jahnke, Agnes A1 - Schwiertz, Carola A1 - Schmeißer, Dieter T1 - Organische Feldeffekttransistoren als Transducer in der Biosensorik T1 - Organic Field Effect Transistors as Biosensors T2 - Technisches Messen N2 - In diesem Beitrag wird der Einsatz neuartiger Sensortypen für die medizinische Diagnostik beschrieben. Diese Sensoren sollen komplett organisch sein und auf dem Prinzip des Feldeffekttransistors basieren. Als Modellsystem für die Anwendung in der Biosensorik soll die Einsatzmöglichkeit dieser Sensoren in der nicht-invasiven Diagnostik der Helicobacter-pylori-Infektion überprüft werden. N2 - In this contribution we describe the investigation of new types of sensors in medical diagnosis. These sensors are completely organic and are based on the principle of organic field effect transistors. As model system for application in medical diagnosis we test the usability of this sensors for the diagnosis of helicobacter pylori. KW - Feldeffekttransistor KW - Biosensorik KW - Helicobacter pylori KW - Field effect transistors KW - biosensors KW - helicobacter pylori Y1 - 2003 U6 - https://doi.org/10.1524/teme.70.12.565.20261 SN - 0171-8096 VL - 70 IS - 12 SP - 565 EP - 568 ER - TY - GEN A1 - Kot, Małgorzata A1 - Łobaza, Justyna A1 - Naumann, Franziska A1 - Gargouri, Hassan A1 - Henkel, Karsten A1 - Schmeißer, Dieter T1 - Long-term ambient surface oxidation of titanium oxynitride films prepared by plasma-enhanced atomic layer deposition: An XPS study T2 - Journal of Vacuum Science and Technology A N2 - The surface oxidation of a titanium oxynitride (TiOxNy) film after long-time storage of 25 month in ambient conditions is investigated. The TiOxNy film is prepared by plasma-enhanced atomic layer deposition using etrakis(dimethylamino)titanium and nitrogen plasma, and the film is characterized by Ar+ ion sputtering of the film surface in combination with x-ray photoelectron spectroscopy (XPS) as well as by angle-resolved XPS. The total thickness of an oxygen-enriched layer at the surface of the TiOxNy films is found to be about 0.7 nm and it consists of a sequence of a 0.4 nm thick TiON/TiO2 enriched layer followed by a 0.3 nm thick TiO2 enriched layer underneath compared to the bulk composition of the film which shows constant values of 29% TiN, 29% TiO2, and 42% TiON. The results suggest that the TiON enrichment takes place initially at the surface followed by a surface and subsurface oxidation. KW - atomic layer deposition (ALD) KW - surface oxidation KW - X-Ray photoelectron spectroscopy (XPS) KW - titanium oxynitride Y1 - 2018 U6 - https://doi.org/10.1116/1.5003356 SN - 0734-2101 SN - 1520-8559 VL - 36 IS - 1 ER -