TY - JOUR A1 - Paloumpa, Ioanna A1 - Yfantis, Alexandros D. A1 - Hoffmann, Patrick A1 - Burkov, Yevgen A1 - Yfantis, Alexandros D. A1 - Schmeißer, Dieter T1 - Mechanisms to inhibit corrosion of Al alloys by polymeric conversion coatings N2 - We introduce a recently developed novel polypyrrole-based coating, which can be formed on the aluminium surface from an aqueous pyrrole solution of fluorozirconic and fluorotitanic acid neutralised with zinc oxide. The composite layer consists of polypyrrole (Ppy) chemisorbed on titanium and zinc oxides and exhibits advanced corrosion resistance. For the investigation of the structure and the corrosion mechanism of the composite corrosion resistant layer we use a photo-electron emission microscope (PEEM). PEEM is especially suitable because it can deliver topographic contrast as well as elemental contrast and chemical information in connection with a variable X-ray source. Additionally, in order to investigate further the corrosion mechanism, but also the role of the alloy in the corrosion process, we examine the aluminium samples with SEM/EDX. The structure of the corrosion resistant layer was investigated before and after accelerated corrosion tests. Our results pointed out the important role of titanium oxide and zinc in the corrosion resistance of our Ppy coating on aluminium. KW - Polypyrrole KW - Fluorozirconates KW - Fluorotitanates KW - Aluminium KW - Corrosion Y1 - 2004 ER - TY - GEN A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim A1 - Dabrowski, Jarek Marek T1 - Silicate Layer Formation at the Pr2O3 / Si(001) Interfaces T2 - Applied Physics Letters N2 - We studied Pr2O3/Si(001) interfaces by synchrotron radiation photoelectron spectroscopy and by ab initio calculations. We show that the interface formed during molecular-beam epitaxy under the oxygen partial pressure above 1%D710-8 mbar consists of a mixed Si-Pr oxide, such as (Pr2O3)(SiO)x(SiO2)y. Neither an interfacial SiO2 nor an interfacial silicide is formed. The silicate formation is driven by a low energy of O in a PrOSi bond and by the strain in the subsurface SiOx layer. We expect that this natural interfacial Pr silicate will facilitate the integration of the high-k dielectric Pr2O3 into future complementary metal-oxide-semiconductor technologies. Y1 - 2004 SN - 1077-3118 VL - 85 IS - 1 SP - 88 EP - 90 ER - TY - JOUR A1 - Schmeißer, Dieter T1 - Covalent and localized contributions of Pr4f states at the interface of Pr2O3 to Si(001) N2 - Resonant photoelectron spectroscopy (PES) at the Pr4d and O1 s absorption edges is used to study the electronic properties at the interface of epitaxially grown Pr2O3 on Si(001).In the electronic structure of bulk Pr2O3, the valence band (VB) states are predominant of Pr6s and O2p atomic parentage. The contribution of Pr4f states is identified from the strong increase of the VB features at the Pr4d resonances. The data at the O1s edge are caused by Raman scattering and resonant Auger decay and reflect the existence of charge transfer (CT) complexes. These complexes are the consequence of a mixed valency caused by ligand-to-Pr4f charge transfer states. The decrease of their intensity is attributed to an increase in covalent bandwidth between the ligand (O2p, Si3p) and Pr4f states. The CT complexes, originally localized now, become broadened and form gap states which fill the gap towards a metallic density of states. The metallic phase may be hindered upon alloying with SiO2 or other oxides. Y1 - 2004 ER - TY - GEN A1 - Lupina, Grzegorz A1 - Dabrowski, Jarek Marek A1 - Formanek, Peter A1 - Schmeißer, Dieter A1 - Sorge, Roland A1 - Wenger, Christian A1 - Zaumseil, Peter A1 - Müssig, Hans-Joachim T1 - Solid-state reaction between Pr and SiO2 studied by photoelectron spectroscopy and ab initio calculations T2 - Materials Science in Semiconductor Processing N2 - We report on the structural and electrical properties of Pr-based high-k dielectric films fabricated by solid-state reaction between metallic Pr and SiO2 underlayers. A non-destructive depth profiling using synchrotron radiation excited photoelectron spectroscopy (SR-PES), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) were employed to examine the chemical composition and microstructure. Ab initio calculations were done to gain insight into the physical processes involved. SR-PES results indicate that Pr deposition at room temperature (RT) leads to the formation of a Pr silicide and a Pr oxide, what is in good agreement with the scenario expected from ab initio calculations. As revealed by TEM and electrical measurements, oxidation of the reacted structures, followed by annealing, results in a stacked dielectric composed of a SiO2-based buffer with an enhanced permittivity and a Pr silicate film with a high dielectric constant. The leakage current density of 10-4 A/cm2 was measured for stacks with capacitance equivalent thickness (CET) of 1.5 nm prepared by evaporation of the Pr layer on a 1.8 nm SiO2 film, followed by oxidation in air ambient and annealing in N2 atmosphere. The capacitance-voltage (C-V) curves exhibit a large flatband voltage (VFB) shift indicating the presence of a positive charge in the stack. Switching away from the Al contacts to Au gate electrodes introduces a significant reduction of the VFB by 1.3 eV, what is much more than the change expected from the work function difference between Al and Au (not, vert, similar0.9 eV). This in turn implies that VFB is strongly affected by the gate interface electrode. KW - High-k dielectrics KW - Photoelectron spectroscopy KW - Interface reaction Y1 - 2004 SN - 1369-8001 VL - 7 IS - 4-6 SP - 215 EP - 220 ER - TY - GEN A1 - Yfantis, Alexandros D. A1 - Tzalas, B. A1 - Lambrakopoulos, S. A1 - Anagnostaki, E. A1 - Schmeißer, Dieter T1 - New chrome free, environmentally friendly methods in chemical processes N2 - It gives an overview of the research work to develop chrom-free methods in different chemical processes. A new class of materials, the conductive polymers, have been studied extensively for their anticorrosion properties. KW - Alloys KW - Polypyrrole KW - Polymers Y1 - 2002 ER - TY - GEN A1 - Lewerenz, Hans-Joachim A1 - Murrell, Chris A1 - Jakubowicz, J. A1 - Aggour, Mohammed A1 - Kanis, M. A1 - Campbell, S. A. A1 - Cox, P. A. A1 - Hoffmann, Patrick A1 - Jungblut, H. A1 - Schmeißer, Dieter T1 - High Resolution Surface analysis of Si Roughenning in Dilute Ammonium Fluoride Solution T2 - Journal of Electroanalytical Chemistry N2 - The initial stages of porous Si formation on Si(111) in dilute ammonium fluoride solution are analysed by photoelectron spectroscopy using synchrotron radiation (SRPES). The PES results in the por-Si formation regime partly support a recent dissolution model. The contribution from the Si 2p surface core level shift shows that 0.35 ML of the surface is still H-terminated after interruption of the conditioning process at the first photocurrent maximum. Two signals shifted in binding energy by 0.8 and 1 eV, respectively, are attributed to reaction intermediates expected from the proposed reaction mechanism and from theoretical calculations using density functional theory (DFT). A distinct roughening is found in in-situ AFM measurements, with a calculated RMS roughness parameter of 2.6 nm. KW - Porous Si KW - transistors KW - Electropolishing KW - Photoelectron spectroscopy KW - AFM KW - Synchrotron radiation Y1 - 2003 SN - 1873-2569 VL - 540 SP - 3 EP - 6 ER - TY - GEN A1 - Appel, Günter A1 - Ade, H. A1 - Gürek, A. G. A1 - Stadler, S. A1 - Mikalo, Ricardo Pablo A1 - Schmeißer, Dieter T1 - Orientation studies of Si-Phthalocyanines sulfonic acids cast on SiOx substrates T2 - Applied Physics / A N2 - Layers of dihydroxy silicon phthalocyanine tetrasulfonic acid and oligo-7-oxo silicon phthalocyanine tetrasulfonic acid were prepared by solution-casting methods. The purity of the material was checked by X-ray photoemission spectroscopy. The orientation of the molecules in respect to the substrate plane was investigated by angle-dependent near-edge X-ray absorption fine-structure spectroscopy. The morphology was characterized by atomic force microscopy. Most samples exhibited a significant orientation that was accompanied by crystalline structures; others had no orientation at all with a dominant amorphous morphology. This behavior indicates that several preparation parameters affect the crystallinity and the orientation of the phthalocyanines. Y1 - 2003 U6 - https://doi.org/10.1007/s003390201320 SN - 1432-0630 VL - 76 IS - 2 SP - 177 EP - 182 ER - TY - GEN A1 - Müller, Klaus A1 - Goryachko, Andriy A1 - Burkov, Yevgen A1 - Schwiertz, Carola A1 - Ratzke, Markus A1 - Köble, J. A1 - Reif, Jürgen A1 - Schmeißer, Dieter T1 - Scanning Kelvin Probe Microscopy and Photoemission electron microscopy of organic source-drain structures T2 - Synthetic Metals N2 - n order to optimize organic field effect transistors (OFETs), the characterisation of active-layer surfaces in terms of their roughness, chemical composition and distribution of surface potentials is important. We report on high-resolution microscopic mapping of organic source-drain structures with P3HT as the semiconductor by scanning Kelvin probe microscopy (SKPM) and photoemission electron microscopy (PEEM). It was shown that PEEM is able to characterise the surface morphology (roughness), the chemical homogeneity and the composition of organic structures. The two-dimensional mapping of surface potentials by SKPM with applied source-drain voltages is shown to be an important ingredient of OFETs failure mode analysis. KW - Photoemission electron microscopy (PEEM) KW - Scanning Kelvin probe microscopy (SKPM) KW - OFET Y1 - 2004 SN - 0379-6779 VL - 146 IS - 3 SP - 377 EP - 382 ER - TY - GEN A1 - Müssig, Hans-Joachim A1 - Dabrowski, Jarek Marek A1 - Wenger, Christian A1 - Lupina, Grzegorz A1 - Sorge, Roland A1 - Formanek, Peter A1 - Zaumseil, Peter A1 - Schmeißer, Dieter T1 - Ultrathin Dielectric Films Grown by Solid Phase Reaction of Pr with SiO2 T2 - MRS Proceedings Y1 - 2004 SN - 1946-4274 VL - 811 ER - TY - GEN A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim T1 - Pr4f occupancy and VB/CB band offsets of Pr2O3 at the interface to Si(001) and SiC(0001) surfaces T2 - MRS Proceedings Y1 - 2004 SN - 1946-4274 VL - 811 ER - TY - JOUR A1 - Hoffmann, Patrick A1 - Schmeißer, Dieter A1 - Soinski, M. S. T1 - Promieniowanie synchrotronowe jako uniwersalne narzedzie badawcze - Proby jego wykorzystania w badaniach struktury zeliwa Y1 - 2004 ER - TY - GEN A1 - Yfantis, Alexandros D. A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter ED - Kainer, Karl Ulrich T1 - Corrosion Protection by Conductive Polymers for Magnesium Alloys T2 - Magnesium, proceedings of the 6th International Conference on Magnesium Alloys and their Applications, November 2003 in Wolfsburg N2 - In this work, we present the experimental data related to the effect of the polypyrrole concentration and the film thickness on the corrosion inhibition properties of these novel polymer coatings. The relative corrosion resistance properties of the films formed from the matrix solutions, where polypyrrole was in situ polymerized and in cases where polypyrrole is dispersed in a form of powder (pigment) in the polyaclylic polymer, are further examined. The evaluation of the experimental data provides significant evidence regarding the mechanism of corrosion inhibition, as well as the optimization of the synthesis and application conditions. KW - corrosion protection KW - conductive polymers for magnesium alloys KW - polypyrrole Y1 - 2004 SN - 3-527-30975-6 SP - 605 EP - 610 PB - Wiley-VCH CY - Weinheim ER - TY - CHAP A1 - Sidorenko, Alexander A1 - Tokarev, Igor A1 - Krenek, Radim A1 - Burkov, Yevgen A1 - Schmeißer, Dieter A1 - Minko, S. A1 - Stamm, Manfred ED - Champion, Yannick ED - Fecht, Hans-Jörg T1 - Generation of Nanostructured Materials from Thin Films of Block Copolymer Assembles T2 - Nano-architectured and manostructured materials, fabrication, control and properties, EUROMAT 2003 Y1 - 2004 SN - 3-527-31008-8 SP - 143 EP - 150 PB - Wiley-VCH CY - Weinheim ER - TY - GEN A1 - Tokarev, Igor A1 - Krenek, Radim A1 - Burkov, Yevgen A1 - Schmeißer, Dieter A1 - Sidorenko, Alexander A1 - Minko, Sergiy A1 - Stamm, Manfred T1 - Microphase separation in thin films of poly(styrene-block-4-vinylpyridine) Copolymer-2-(4-Hydroxybenzeneazo) benzoic Acid Assembly T2 - Macromolecules N2 - The fine structure of thin films of poly(styrene-block-4-vinylpyridine) copolymer-2-(4'-hydroxybenzeneazo)benzoic acid (PS-PVP+HABA) assembly has been studied using the combination of atomic force microscopy, ellipsometry, X-ray reflectivity, GISAXS, XPS, and XPEEM. The films consist of cylindrical nanodomains formed by PVP+HABA associates surrounded by PS matrix. Alignment of the domains can be switched upon exposure to vapors of different solvents from the parallel to perpendicular orientation and vice versa with respect to the surface plane. Swelling in 1,4-dioxane leads the system from the cylindrical to the spherical morphology. Solvent evaporation results in a shrinkage of the matrix in the vertical direction and subsequent merging of the spheres into the perpendicularly aligned cylinders. The cylinders form a regular hexagonal lattice with a spatial period of 25.5 nm. On the other hand, vapors of chloroform induce in-plane alignment. The films consist of parallel layers of the cylinders separated by PS matrix and demonstrate the fingerprint-like structure. The nanocylinders of PVP+HABA are packed into a distorted hexagonal lattice exhibiting 31 nm in plane and 17 nm vertical periodicity. In both cases a thin wetting layer is found at the polymer-substrate interface. The free surface is enriched with PS. Y1 - 2005 SN - 1520-5835 VL - 38 IS - 2 SP - 507 EP - 516 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 - GEN A1 - Lamprakopoulos, Stelios A1 - Schmeißer, Dieter A1 - Anastassopoulou, Jane A1 - Theophanides, Theophile A1 - Yfantis, Alexandros D. T1 - An FTIR study of the role of H2O and D2O in the aging mechanism of conductive polypyrroles T2 - Synthetic Metals N2 - In the present work the role of H2O was studied by conductivity measurements and FTIR spectroscopy using the isotopic effect of deuterium in order to elucidate the aging mechanism of conductivity of polypyrroles. Polypyrrole was prepared with PTS as a dopant, by using deuterated water. Conductivity measurements showed changes due to structural water and atmospheric humidity. The FTIR absorption spectra indicated that the most probable structure of polypyrrole is the two-dimensional one. This finding could be attributed to the inhibition of polypyrrole's IR modes. The infrared spectrum analysis show that the gamma -NH bending mode of pyrrole has significantly changed after polymerization of pyrrole and this result is in accordance with XPS measurements. KW - Polypyrrole KW - Conductivity KW - FTIR KW - Isotopic effect Y1 - 2004 U6 - https://doi.org/10.1016/j.synthmet.2004.03.006 SN - 0379-6779 VL - 144 IS - 3 SP - 229 EP - 234 ER - TY - JOUR A1 - Schmeißer, Dieter T1 - Pr2O3/Si(001) interface reactions and stability N2 - We show that an interfacial silicate is formed in a natural way between Si(0 0 1) and the deposited Pr2O3 film if a sufficient amount of oxygen is provided during deposition, as during electron beam evaporation from Pr6O11 source. We provide arguments from results of ab initio calculations and we present a ternary phase diagram of the Pr-O-Si system obtained for epitaxial films from non-destructive depth profiling data acquired by synchrotron radiation and photoelectron spectroscopy (SR-PES) at the undulator beam line U49/2-PGM2. The composition of the interfacial layer is (Pr2O3)(SiO)x(SiO2)y, with x+y between 2 and 6 and depends on the growth condition and distance from the substrate. No interfacial SiO2 and no interfacial silicide is formed during growth. The ternary phase diagram indicates that this non-stoichiometric pseudobinary alloy is stable on Si up to high temperatures, without phase separation into Pr2O3 and SiO2. Therefore, a complete re-engineering of the CMOS process may be not necessary. KW - High-k-material KW - Pr2O3/Si(0 0 1) interface KW - Photoelectron spectroscopy KW - Ab initio calculations KW - CMOS Y1 - 2004 ER - TY - GEN A1 - Sidorenko, Alexander A1 - Tokarev, Igor A1 - Krenek, Radim A1 - Burkov, Yevgen A1 - Schmeißer, Dieter A1 - Stamm, Manfred T1 - XPEEM investigations of 2D hierachical array of Ni nanorods using block copolymer templates Y1 - 2004 ER - TY - JOUR A1 - Schmeißer, Dieter T1 - Cooper minimum observed for the Pr5s and Pr5p states in Pr2O3 Y1 - 2004 ER - TY - CHAP A1 - Schmeißer, Dieter A1 - Lupina, Grzegorz A1 - Müssig, Hans-Joachim T1 - High reactivity of Pr on oxide covered 4H-SiC T2 - Bessy annual report 2003 Y1 - 2004 SP - 408 EP - 409 PB - Bessy CY - Berlin ER - TY - JOUR A1 - Schmeißer, Dieter T1 - Interface reactivity of Pr and SiO2 at 4H-SiC(0001) N2 - We use photoelectron spectroscopy to characterize the reactivity of Pr evaporated on SiO2 covered 4H-SiC substrates. We analyze the Si2p, C1s, and O1s core levels and find that Pr reacts at RT with the SiO2 layer to form Pr-silicate. In addition also Pr-silizide is formed as well as Pr-carbides. While the latter are formed as reaction intermediates after Pr evaporation, the Pr-silicate layer is formed upon annealing to 300 °C and is stable up to 800 °C. KW - Photoelectron spectroscopy KW - 4H-SiC KW - Interface reactivity KW - High-k dielectric layer Y1 - 2005 ER - TY - JOUR A1 - Schmeißer, Dieter T1 - Pr4f occupancy and origin of gap states at the Pr2O3 / Si (001) interface Y1 - 2005 ER - TY - JOUR A1 - Seifarth, Olaf A1 - Burkov, Yevgen A1 - Goryachko, Andriy A1 - Schmeißer, Dieter A1 - Sydorenko, Alexander A1 - Krenek, Radim A1 - Stamm, Manfred T1 - Photoelectron spectroscopy and microscopy on Cr nano particels embedded into block copolymers Y1 - 2005 ER - TY - CHAP A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim T1 - Pr-silicate formation on SiO2 covered 3C-SiC(111) T2 - Physics of semiconductors, 27th International Conference on the Physics of Semiconductors Y1 - 2005 SN - 0-7354-0257-4 SP - 75 EP - 76 PB - AIP, American Inst. of Physics CY - New York, NY ER - TY - JOUR A1 - Wehner, Stefan A1 - Schmeißer, Dieter A1 - Hoffmann, Patrick T1 - Spatiotemporal patterns of external noise-induced transitions in a bistable reaction-diffusion system : Photoelectron Emission Microscopy experiments and modeling Y1 - 2005 ER - TY - GEN A1 - Lupina, Grzegorz A1 - Schroeder, Thomas A1 - Dabrowski, Jarek Marek A1 - Schmeißer, Dieter A1 - Hoffmann, Patrick T1 - Praseodymium silicate layers with atomically abrupt interface on Si(100) T2 - Applied Physics Letters Y1 - 2005 SN - 0003-6951 VL - 87 IS - 5 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 - JOUR A1 - Goryachko, Andriy A1 - Paloumpa, Ioanna A1 - Beuckert, Guido A1 - Burkov, Yevgen A1 - Schmeißer, Dieter T1 - The Interaction of Pr2O3 with 4H-SiC(0001)surface JF - Physica status solidi / C N2 - Praseodymium oxide (Pr2O3) as a hetero-oxide on SiC(0001) represents a promising semiconductor / high-K dielectric material combination. We prepared thin films (<3 nm) of Pr2O3 on 4H-SiC(0001) surfaces by a wet chemical process involving aqueous solutions of Pr(NO3)3. Synchrotron radiation photoelectron spectroscopy (SR-PES) is used to study the chemical composition of these films after deposition and annealing in 300-900 %B0C range. The Si2p and C1s core level emissions are analysed in detail and reveal that praseodymium-silicate is formed at the interface. Our data are compared to corresponding studies of the Pr2O3 interaction with Si(001) surfaces. Y1 - 2004 SN - 1610-1634 VL - 1 IS - 2 SP - 265 EP - 268 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 -