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 - 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 - GEN A1 - Müller, Klaus A1 - Burkov, Yevgen A1 - Schmeißer, Dieter T1 - PEEM and my-NEXAFS of Cu-In-S2-surfaces T2 - Thin Solid Films N2 - Polycrystalline CuInS2 samples are an ideal system for photoemission electron microscope studies. The polycrystalline grains have a diameter of approximately 5 small mu, Greekm and the system is expected to be highly inhomogeneous because of the existence of many sub-phases. We used a recently established procedure to reproducibly obtain stoichiometric CuInS2-surfaces and follow the changes in the morphology, the elemental inhomogeneous distribution, and the development of the electronic structure upon its preparation. We find that the individual grains trend to coagulate, the surface composition becomes more homogeneous, and identify characteristic features of the unoccupied DOS. KW - CuInS2 films KW - Annealing-process KW - PEEM KW - small mu KW - NEXAFS Y1 - 2003 SN - 0040-6090 VL - 431-432 SP - 307 EP - 311 ER - TY - GEN A1 - Müller, Klaus A1 - Paloumpa, Ioanna A1 - Schmeißer, Dieter T1 - Carbon-plot-microstructuring for all-polymer-transistors T2 - Synthetic Metals N2 - This contribution describes the use of a low-cost technology to produce organic microstructures for electronically applications. With a computer driven plotter, substrates like printing foil and colloidal graphite (diluted in water) for the electrodes, we realised channel lengths of 20±10 microm. Compared with transistor devices, fabricated using conventional photolithographic methods and the same semiconducting material, this technique is a hopeful approach to produce microelectronic structures that are low-cost and all-organic. KW - Ten micrometer carbon-plot KW - Organic field-effect-transistors KW - Low-cost-technique Y1 - 2003 SN - 0379-6779 VL - 138 IS - 1-2 SP - 271 EP - 273 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 - 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 - JOUR A1 - Müller, Klaus T1 - PEEM studies of KCN-etched CuInS2 surfaces Y1 - 2004 ER - TY - JOUR A1 - Müller, Klaus T1 - PEEM imaging contrast in an operating organic electronic device 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 - 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 - 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 - 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 -