TY - JOUR A1 - Hoffmann, Patrick A1 - Mikalo, Ricardo Pablo A1 - Schmeißer, Dieter T1 - Si(001) surface oxidation by N2O N2 - Ultra-thin homogeneous oxynitride films are prepared on Si(001). The Si surface is cleaned in UHV by heating (flashing) and is exposed to different pressures of N2Oat altered temperatures. Thus oxynitride layers of different thickness and different properties are grown depending on the N2O pressure and the Si temperature. This isillustrated by a schematic diagram. The properties of the different oxynitride layers were studied by a combined photoemission electron microscopy (PEEM) andphotoelectron spectroscopy (PES) investigation using highly monochromatic synchrotron radiation. The amount of oxygen and nitrogen incorporated in the oxynitridelayers is determined from the PES measurements. The typical surface morphology for different preparation conditions is shown in PEEM images. KW - SI(100) KW - dielectric KW - Oxynitride KW - Interface KW - SI KW - NO Y1 - 2002 ER - TY - JOUR A1 - Mikalo, Ricardo Pablo A1 - Schmeißer, Dieter T1 - Electric contacts on conductive polymers: sodium on poly(3-hexylthiophene-2,5-diyl) N2 - Sodium as a model contact with low work function on regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) films was investigated. The interface was studied by X-rayand ultraviolet photoelectron spectroscopy in the range of 0.13 up to 1.8 metal atoms per hexylthiophene unit. In the range of 0.13-0.26 sodium atoms per hexylthiophenering we find a change inthe surface potentials which is interpreted as a discharge of positive surface charges. Sodium exposures above 0.5 sodium atoms perhexylthiophene unit exhibit a reduction of the thiophene sulfur due to the formation of sodium sulfide and breaking of the thiophene ring. Y1 - 2002 ER - TY - JOUR A1 - Yfantis, Alexandros D. A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter A1 - Yfantis, Alexandros D. T1 - Novel corrosion-resistant films for Mg alloys N2 - A novel method for the corrosion inhibition of Mg, alloys, based on the formation of a thin polyacrylic-polypyrrole film, is presented. The film was created after simpleimmersion of the samples in a specially formulated emulsion of polyacrylic and polypyrrole polymers. The synthesis conditions were studied, as well as the resultingcorrosion resistance of coated magnesium foils (AZ31) in terms of corrosion rate in neutral aqueous NaCl solutions. The relative ratio of polyacrylic polymer topolypyrrole was found to be important for the film properties. Furthermore, only in situ polymerisation of pyrrole in the polyacrylic emulsion can provide advancedcorrosion proper-ties in relatively thin films (2-5 mum). Blending of polypyrrole powder with the polyacrylic emulsion gives rise to thick films (20 mum) with reducedcorrosion-inhibition properties. The corrosion rate was only weakly dependent on the film thickness of these novel coatings. We argue that the mechanism of corrosioninhibition is related to the formation of a thin passive layer of chemisorbed polypyrrole polymers or oligomers on the native magnesium oxide of the C surface. Thestructure is further stabilised by polyacrylic polymer chains interacting as dopants of polypyrrole. The method is environmentally friendly: non-toxic chemicals are used,no rinsing is required, etc. The advanced corrosion-inhibition properties of the films. as well as the simple application process on the metal surface, provide significantpotential for the industrial application of the method. KW - polypyrrole KW - polyacrylic KW - coating KW - magnesium KW - corrosion inhibition Y1 - 2002 ER - TY - JOUR A1 - Hoffmann, Patrick A1 - Mikalo, Ricardo Pablo A1 - Schmeißer, Dieter T1 - PEEM - a spectromicroscopic tool for mc-Si surface evaluation N2 - The photo emission electron microscope (PEEM) with its direct imaging of the sample surface is a convenient tool for fast evaluation of large sample areas. It is possibleto handle samples with a size of 30 mm x 30 mm.With PEEM it is possible to visualise grain boundaries and crystal displacements without removing the native oxide. No special sample treatment is needed exceptchemical polishing of the sample surface and a HF-dip to obtain a thin (1 ... 2 nm) oxide layer.The quality of that oxide was proofed by high resolution photo electron spectroscopy (PES) at a synchrotron. The results were compared to native oxide onsingle-crystalline Si and no suboxides (e.g. SiO) were found. Our spectromicroscopic PEEM measurements show no difference in the oxide qualities of different grainsand on grain boundaries or crystal displacements. Furthermore no difference in the binding energy of Si2p core levels were found.In addition to grain boundaries other spot-like features were found on the sample surface. These could be identified in some cases as precipitation of Ca underneath thenative oxide. KW - multicrystalline silicon KW - photoelectron spectroscopy KW - PEEM Y1 - 2002 ER - TY - JOUR A1 - Müller, Klaus A1 - Hoffmann, Patrick A1 - Milko, S. A1 - Burkov, Yevgen A1 - Schmeißer, Dieter T1 - PEEM and µ-NEXAFS of Cu-In-S-Surfaces N2 - The composition of CuInS2-films tends to differ from the ideal ratio of 1:1:2. A molecularlyvariation of dm=[Cu]/[In]-1 not equal 0 occurs due to the formation of binary phases as segregation's at the surface, as crystallites in the bulk of the film or at the surface of grains [1]. Furthermore, the range of homogeneity of the phase CuInS2 is relatively large caused by a low enthalpy of formation of defects like Cu-vacancies [2]. Segregation's at surfaces can be removed by KCN etching or by an electrochemical process [3, 4] We investigated the effect of an in-situ-heat-treatment of samples, prepared in the Cu-rich regime with additional amounts of copper, deposited on the surface of the Cu-In-S-films.We used Cu-In-S-films on molybdenum, prepared from precursors of Cu/In and a following reactive annealing-process in a sulphur-atmosphere. The experiments were performed as follows: The surface of the films was cleaned in situ to remove CuS-Phases by Argon-bombardment. The thin layers of additional Copper were prepared by evaporation of copper metal in Knudsen-cells. The thickness of this copper-films is in the range of monolayers, revealed by a calibration with copper on iron-substrates. After this deposition the samples were heated up to several temperatures (up to 550 ºC) for ten minutes, respectively. Here the molybdenum back-contact was used as electrical heater. Y1 - 2002 ER - TY - JOUR A1 - Batchelor, David R. A1 - Hoffmann, Patrick A1 - Schmeißer, Dieter T1 - Photoemission study of Aluminium Steel cold welded joints N2 - Aluminium and Stainless Steel bi-metal material is extremely versatile and is used in a wide range of products; from cooking utensils to high technology applications such as automobile manufacture and Synchrotron radiation instrumentation. As a consequence of this wide range of applications the study of the formation of Aluminium Steel junctions and the bonding mechanism is of considerable industrialimportance [1-3].In a previous publication [4] evidence for a chemical bond, alloying at the interface was found. As the monochromator focus and welded region are similar in size about 200 µm (the actual interface from SEM is an order of magnitude smaller) a simple photoemission experiment of translating the sample perpendicular (vertically, weld horizontal) to the weld and measuring spectra was performed. Y1 - 2002 ER - TY - JOUR A1 - Jäckel, B. A1 - Thißen, A. A1 - Hunger, Ralf A1 - Klein, A. A1 - Jaegermann, Wolfram A1 - Hoffmann, Patrick A1 - Schmeißer, Dieter T1 - Focus IS-PEEM investigations at U49/II: experimental determination of a magnification function, the contrast mechanism and the spectral resolution Y1 - 2002 ER - TY - JOUR A1 - Schmeißer, Dieter A1 - Hoffmann, Patrick T1 - Characterisation of the PrOx/Si(001) Interface by Photoelectron Spectroscopy Y1 - 2002 ER - TY - JOUR A1 - Seyller, Th. A1 - Sieber, N. A1 - Graupner, R. A1 - James, D. A1 - Riley, J. A1 - Leckey, R. A1 - Polcik, M. A1 - Schmeißer, Dieter T1 - High Resolution Photoelectron Spectroscopy on SiC Surfaces Y1 - 2002 ER - TY - JOUR A1 - Pop, D. A1 - Winter, B. A1 - Batchelor, David R. A1 - Freyer, W. A1 - Weber, R. A1 - Bröcker, D. A1 - Hertel, I. V. A1 - Schmeißer, Dieter A1 - Widdra, Wolf T1 - Copper Satellite Structure in Porphyrazine Compounds Y1 - 2002 ER - TY - JOUR A1 - Gracia, F. A1 - Martin-Concepcion, A. I. A1 - Barranco, A. A1 - Holgado, J. P. A1 - Espinos, J. P. A1 - Yubero, F. A1 - Batchelor, David R. A1 - Schmeißer, Dieter A1 - Gonzalez-Elipe, A. R. T1 - XAS investigation of texture in TiO2 thin films prepared by IBICVD Y1 - 2002 ER - TY - JOUR A1 - Sieber, N. A1 - Seyller, Th. A1 - Graupner, R. A1 - Ley, L. A1 - Mikalo, Ricardo Pablo A1 - Hoffmann, Patrick A1 - Batchelor, David R. A1 - Schmeißer, Dieter T1 - Wet-chemical preparation of silicate adlayer reconstructed SiC(0001) surfaces as studied by PIES and LEED N2 - We have studied the surface chemistry of 6H-SiC(0001) and 6H-SiC (000 (1) over bar) after wet-chemical treatment using photoelectron spectroscopy (PES) andlow-energy electron diffraction (LEED). The origin of chemically shifted components in the Si2p and C1s spectra is discussed in the light of previous studies onwet-chemically prepared surfaces and on silicate adlayer reconstructed surfaces. On 6H-SiC(0001) an ordered silicate adlayer was prepared by etching the surface withsulfuric acid based agents. KW - Core level KW - Photoelectron spectroscopy KW - Synchrotron radiation KW - Wet-chemical preparation OXIDE Y1 - 2002 ER - TY - JOUR A1 - Batchelor, David R. A1 - Follath, Rolf A1 - Schmeißer, Dieter T1 - Commissioning Results of the BTUC-PGM beamline Y1 - 2001 ER - TY - JOUR A1 - Lopez, A. A1 - Bitzer, Thomas A1 - Heller, Thomas A1 - Richardson, Neville V. T1 - Adsorption of water on alkoxy modified Si(1 0 0), Si(1 1 3) and Si(1 1 5) surfaces Y1 - 2001 ER - TY - JOUR A1 - Lopez, A. A1 - Bitzer, Thomas A1 - Heller, Thomas A1 - Richardson, Neville V. T1 - Adsorption of maleic anhydride on Si(1 0 0)-2 x 1 JF - Surface Science Y1 - 2001 SN - 0039-6028 VL - 477 SP - 219 EP - 226 ER - TY - JOUR A1 - Mikalo, Ricardo Pablo A1 - Appel, Günter A1 - Hoffmann, Patrick A1 - Schmeißer, Dieter T1 - Band Bending in Doped Conducting Polypyrrole Interaction with Silver Y1 - 2001 ER - TY - JOUR A1 - Mikalo, Ricardo Pablo A1 - Appel, Günter A1 - Schmeißer, Dieter T1 - Conductivity of Silver exposed Polypyrrole Films Y1 - 2001 ER - TY - JOUR A1 - Mikalo, Ricardo Pablo A1 - Hoffmann, Patrick A1 - Batchelor, David R. A1 - Schmeißer, Dieter A1 - Lloyd Spetz, Anita A1 - Lundström, Ingemar T1 - Comparison of HF and ozone treated SiC surfaces Y1 - 2001 ER - TY - JOUR A1 - Schmeißer, Dieter A1 - Mikalo, Ricardo Pablo A1 - Hoffmann, Patrick A1 - Seyller, Th. A1 - Ley, L. A1 - Lloyd Spetz, Anita T1 - Oxide growth on SiC (0001) surfaces Y1 - 2001 ER - TY - JOUR A1 - Sieber, N. A1 - Mantel, B. F. A1 - Seyller, Th. A1 - Ristein, J. A1 - Ley, L. A1 - Heller, Thomas A1 - Batchelor, David R. A1 - Schmeißer, Dieter T1 - Electronic and chemical passivation of hexagonal 6H-SiC surfaces by hydrogen termination Y1 - 2001 ER - TY - JOUR A1 - Schmeißer, Dieter A1 - Paloumpa, Ioanna A1 - Hoffmann, Patrick A1 - Burkov, Yevgen A1 - Yfantis, Alexandros D. A1 - Yfantis, Alexandros D. T1 - Preventing Corrosion of Aluminium Alloys by Polymeric Coatings N2 - Aluminium is a material of everyday use in many applications,like automobile,aero-space or cookware,due to its specialproperties (low density,low weight,strength,easy to form and cast,abundance etc).Although aluminium is a reactive metal,italso has a significant corrosion resistance because of a thin,protective oxide layer which is generally stable in air and aqueous solutions.However,pores within the oxide film and other defects caused from alloying elements can lead to local corrosion and the formation of pits. Y1 - 2003 ER - TY - JOUR A1 - Müller, Klaus A1 - Milko, S. A1 - Schmeißer, Dieter T1 - Preparation of stoichiometric CuInS2-surfaces - an XPS, UPS-study JF - Thin Solid Films N2 - CuInS2 films are investigated with photoelectron spectroscopy. We find significant deviation from the stoichiometric composition depending on the preparation on the films. For Cu-rich films (start composition) we show that by Ar sputtering and annealing the surface composition varies along a binary cut of the Cu-In-S ternary phase diagram. We also present a novel technique which brings the surface composition close to the stoichiometric stability range of the CuInS2 phase. The technique used the evaporation of Cu on the sputter cleaned surface. KW - Stoichiometric CuInS2-films KW - Annealing KW - XPS KW - UPS Y1 - 2003 SN - 0040-6090 VL - 431-432 SP - 312 EP - 316 ER - TY - JOUR A1 - Bär, Werner T1 - Schnelle Biosensorik für die medizinische Diagnostik N2 - In diesem Beitrag beschreiben wir ein gemeinsames Forschungsvorhaben, welches den Einsatz neuartiger Sensortypen in der medizinischen Diagnostik zum Inhalt hat.Diese Sensoren sollen komplett organisch sein und auf dem Prinzip des Feldeffekttransistors basieren. Die Vorteile des organischen Aufbaus liegen auf der Hand: Die organischen Komponenten sind billiger herzustellen und zu handhaben als anorganische, können leichter chemisch durch Funktionalisierung modifiziert werden und können sogar in-vitro eingesetzt werden. Anderseits bietet das Prinzip des Feldeffekttransistors neben einer ca. 1000-fachen Verstärkung der Messsignale die Möglichkeit, simultan verschiedene physikalisch-chemische Wechselwirkungsprozesse des Analytenmit dem Polymer auszuwerten (siehe Forum, Heft 13).Als Modellsystem für die Anwendung in der Biosensorik soll die Einsatzmöglichkeit dieser Sensoren in der Nicht-invasiven Diagnostik der Helicobacter pylori- Infektion überprüft werden. Zum Einen existieren hier andere Nachweisverfahren, die als Validierung dienen können, aber den Nachteil haben, das sie relativ teuer und langwierig sind. Zum anderen hätte die Sensorik mit einem Transistor, dem Grundbaustein mikroelektronischer Schaltungen, den Vorteil, daß die Messung direkt, also online erfolgen könnte. Y1 - 2003 ER - TY - JOUR A1 - Schmeißer, Dieter T1 - Resonant photoemission at the Pr2O3 /Si(001) interface N2 - In resonant photoemission studies photoelectron spectroscopy (PES) is done at photon ener-giesthat enable the excitation from a deep core hole to the empty conduction band states. Atresonant condition only such states are selectively enhanced which allow an optical couplingof the core hole to the empty conduction band states. Information is to be gained from theshape of the particular resonance and by a comparison of the valence band data at excitationenergies off and on resonance. Such studies provide information on the electronic structure, inparticular how to separate individual contributions in the valence band and conduction bandregime. Y1 - 2003 ER - TY - JOUR A1 - Hunger, Ralf T1 - Commissioning of the Solid/Liquid Analysis System SoLiAS N2 - The SoLiAS experimental station is a versatile preparation system dedicated to theinvestigation of solid/liquid interfaces with synchrotron radiation induced photoelectronspectroscopy SPS. During 2002 the system was installed at BESSY and succesfullycommissioned at beamlines TGM 7 and U49/2. Y1 - 2003 ER - 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 - 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 - JOUR A1 - Burkov, Yevgen T1 - Comparison on Focus-PEEM and Elmitec-PEEM Y1 - 2004 ER - TY - JOUR A1 - Hoffmann, Patrick T1 - Photoemission studies of very thin (<10nm) silicon oxynitride (SiOxNy) layers formed by PECVD N2 - The "ITRS Roadmap" suggests the necessity of working out the processing methods allowing formation of ultrathin dielectric layers with higher values of the dielectric permittivity than for silicon dioxide. The silicon oxynitride layers (SiOxNy) seem to be the most natural compromise. But still none of high temperature methods used for its formation can be seriously considered as final solution for future ULSI-CMOS ICs production due to the inevitable formation of nitride monolayers just at the silicon-insulator interface. The main scope of this investigation is to check if this is true. KW - Semiconductors KW - Thin films KW - Vapour deposition KW - Photoelectron spectroscopies KW - Synchrotron radiation Y1 - 2004 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 - JOUR A1 - Hoffmann, Patrick T1 - Oxynitride on 4H-SiC (0001) N2 - It will be reported on the growth of oxynitride ultra-thin layers (<2 nm) on (0 0 0 1)-oriented 4H-SiC surfaces. The oxynitride layers were grown by a thermal treatment of the samples in low pressure (up to 1000 Pa) N2O ambient. By varying the growth conditions (N2O pressure, sample temperature, growth time) different layers were made. The highest nitrogen incorporation was found to be at high temperatures and low N2O pressures.The grown layers were investigated by photoelectron spectroscopy (XPS) for chemical analysis. Concerning the chemical analysis, the general nitrogen content of the samples is compared at different preparation conditions. The films are found to consist mainly of SiO2 and small fraction of silicon nitride. Only a tenth of the nitrogen was incorporated as oxynitride. The results obtained for oxynitride thin films on 4H-SiC are compared to similarly prepared oxynitride layers on Si(1 1 1) investigated in the past. Furthermore, an additional source of nitrogen due to dopand diffusion in the SiC single crystal is reported. KW - Silicon carbide KW - Oxynitride KW - N2O KW - Photoelectron spectroscopy Y1 - 2005 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 - JOUR A1 - Schmeißer, Dieter T1 - Cooper minimum observed for the Pr5s and Pr5p states in Pr2O3 Y1 - 2004 ER - TY - JOUR A1 - Hoffmann, Patrick T1 - Chemical state depth profiling of ultra-thin oxynitride layers by photoelectron spectroscopy Y1 - 2004 ER - TY - JOUR A1 - Traeger, S. T1 - A PEEM study of lateral inhomogeneities on etched CdTe(110) surfaces Y1 - 2004 ER - TY - JOUR A1 - Müller, Klaus T1 - PEEM studies of KCN-etched CuInS2 surfaces Y1 - 2004 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 - Müller, Klaus T1 - PEEM imaging contrast in an operating organic electronic device 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 - JOUR A1 - Sohal, Rakesh T1 - Pr-Silicate formation on SiO2 covered SiC surfaces Y1 - 2005 ER - TY - JOUR A1 - Torche, Mohamed T1 - The interaction of titanium to Pr2O3 thin films dielectrics Y1 - 2005 ER - TY - JOUR A1 - Hoffmann, Patrick T1 - Oxynitride Grotwth on 4H-SiC(0001) by N2O Y1 - 2005 ER - TY - JOUR A1 - Müller, Klaus T1 - Spectro-Microscopic Characterisation of CuInS2 Surfaces N2 - hotoemission electron microscopy (PEEM) is used to study CuInS2 surfaces. CuInS2 (CIS) is used as polycrystalline absorber layer for thin film solar cells. A characterisation in terms of morphological information, elemental distribution, and of doping inhomogeneities at the surface is very important. We demonstrate that the method is capable for such surface studies in high lateral resolution. The use of synchrotron radiation allows the visualization of chemical inhomogeneities in single grains. By taking PEEM images around the absorption edges of Cu, In, or S, we are able to map elemental distributions, separated from morphology-dependent information in the PEEM image. KW - High-resolution PEEM KW - CuInS2 KW - Solar cells KW - Surface characterisation Y1 - 2005 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 - 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 - JOUR A1 - Müller, Klaus A1 - Scheer, R. A1 - Schmeißer, Dieter A1 - Burkov, Yevgen T1 - Preparation of stoichiometric CuInS2-Surfaces JF - Thin Solid Films KW - preparation Y1 - 2004 SN - 0040-6090 VL - 451–452 SP - 120 EP - 123 ER - TY - JOUR A1 - Müller, Klaus A1 - Burkov, Yevgen A1 - Schmeißer, Dieter T1 - Photo-Emission-Electron-Microscopy for Characterization of an Operating Organic Electronic Device KW - photo-emission-electron-microscopy Y1 - 2006 ER - TY - JOUR A1 - Schmeißer, Dieter T1 - The Consequences of anisotropic Diffusion and Noise: PEEM at the CO Oxidation Reaction on Stepped Ir(111) Surfaces KW - Ir(111) Surfaces Y1 - 2006 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 - Domaradzki, Jarosław A1 - Kaczmarek, Danuta A1 - Schmeißer, Dieter A1 - Beuckert, Guido T1 - Microstructure and Optical Properties of TiO2 Thin Films Prepared by Low Pressure Hot Target Reactive Magnetron Sputtering Y1 - 2006 ER - TY - JOUR A1 - Hoffmann, Patrick A1 - Wehner, Stefan A1 - Schmeißer, Dieter T1 - Noise-Induced Spatiotemporal Patterns in a Bistable Reaction-Diffusion System: Photoelectron Emission Microscopy experiments and Modeling of the CO Oxidation Reaction on Ir(111) Y1 - 2006 ER -