TY - CHAP A1 - Fischer, Christian B. A1 - Rohrbeck, Magdalena A1 - Wehner, Stefan A1 - Richter, Matthias A1 - Schmeißer, Dieter T1 - Diamond-Like Carbon Coatings on Selected Plastic Materials T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 47 N2 - The manufacturing of synthetic materials and their wide range of use for daily life is accompanied by essential requirements. Besides the basic performance of materials such as flexibility, elasticity, fracture strength and chemical resistance, further determinants are long term stability or biocompatibility. To overcome mismatches in surface characteristics of optimal parent material they can be customized for their intended use resulting in suitable coatings for profitable applications. The determining factor for such modifications is the preservation of basic material performance in addition to the benefit of further advantages like changed adhesive, improved repellent or antibacterial behavior. Protective coatings of selected plastic materials have been realized by depositing a few layers of diamond-like carbon (DLC). The assembly of soft plastic material and robust DLC coating is important for the resulting material characteristics. The detailed understanding of materials interphasing between these unequal materials and the conjunction of carbon centers in chemically different neighborhood is part of the presented work. Results will be transferable to other plastic materials with diverse needs, e.g. energy storage devices, water treatments and coatings for everyday commodities or industrial parts. Y1 - 2012 UR - http://www.dpg-verhandlungen.de/year/2012/conference/berlin/part/o/session/66/contribution/9 SN - 0420-0195 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Rohrbeck, Magdalena A1 - Fischer, Christian B. A1 - Wehner, Stefan A1 - Richter, Matthias A1 - Schmeißer, Dieter T1 - Diamond-Like Carbon Coatings on Industrial Polyethylene Surfaces T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 47 N2 - Synthetic materials are used in a wide variety of fields. Depending on the intended application the plastic material must meet specific requirements. Since the material always interacts with its environment, particular attention is required regarding the surface. Possible damage of the plastic material and further risks could be caused by the adhesion of bacteria, biofilm formation and encrustations. Therefore, bacteria-repellent coatings and surface-modified materials that allow for an effective removal of adhered bacteria are of extremely high interest for many applications. In this study Polyethylene (PE) is chosen as simplest model for relevant plastic materials. Surface modification of PE samples is accomplished by plasma-deposited diamond-like carbon (DLC) coatings to achieve increased abrasion strength and bacterial resistance. Two types of nanometer-scaled DLC films with different layer thicknesses are compared by multiscale microscopic analysis. Further spectroscopic measurements with synchrotron radiation are performed. These results will provide an enhanced understanding of layer formation at the interface between the basic plastic material and the DLC coating and will possibly lead to optimal parameters for the surface coating to achieve improved product characteristics. Y1 - 2012 UR - http://www.dpg-verhandlungen.de/year/2012/conference/berlin/part/o/session/35/contribution/28 SN - 0420-0195 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Richter, Christian A1 - Lindemann, Jens A1 - Römer, Ronald A1 - Wolff, Matthias ED - Wirsching, Günther T1 - Das Labor für kognitive Systeme an der BTU Cottbus-Senftenberg T2 - Tagungsband, 26. Konferenz Elektronische Sprachsignalverarbeitung, 25.-27.03.2015, Eichstätt Y1 - 2015 SN - 978-3-95908-000-2 SP - 240 EP - 247 PB - TUDpress CY - Dresden ER - TY - GEN A1 - Schmeißer, Dieter A1 - Haeberle, Jörg A1 - Richter, Matthias A1 - Brazda, Petr T1 - Spin State and Satellite Structures of ε-Fe₂O₃ as determined by Resonant Photoelectron Spectroscopy T2 - Nuclear Instruments and Methods in Physics Research B N2 - We use resonant photoelectron spectroscopy at the Fe2p and the O1s absorption edges to report on spectroscopic investigation of Fe-oxides nanoparticles. We discuss the spectroscopic details like multiple Auger decays, satellite emission in the X-ray absorption process and the core level data. We explain these data by a novel mechanism in which the resonant excitation between Fe3d and Fe4s states are involved. This mechanism is observed when the photo-excited electron becomes polarized by the electron–hole pairs existing in the conduction and valence bands. KW - Resonant photoelectron spectroscopy KW - ε-Fe2O3nano particles KW - Satellite emission Y1 - 2015 U6 - https://doi.org/10.1016/j.nimb.2015.08.062 SN - 0168-583X VL - 2015 IS - 364 SP - 127 EP - 131 ER - TY - GEN A1 - Das, Chittaranjan A1 - Richter, Matthias A1 - Tallarida, Massimo A1 - Schmeißer, Dieter T1 - Electronic properties of atomic layer deposited films, anatase and rutile TiO2 studied by resonant photoemission spectroscopy T2 - Journal of Physics D: Applied Physics N2 - The TiO2 films are prepared by atomic layer deposition (ALD) method using titanium isopropoxide precursors at 250 °C and analyzed using resonant photoemission spectroscopy (resPES). We report on the Ti2p and O1s core levels, on the valence band (VB) spectra and x-ray absorption spectroscopy (XAS) data, and on the resonant photoelectron spectroscopy (resPES) profiles at the O1s and the Ti3p absorption edges. We determine the elemental abundance, the position of the VB maxima, the partial density of states (PDOS) in the VB and in the conduction band (CB) and collect these data in a band scheme. In addition, we analyze the band-gap states as well as the intrinsic states due to polarons and charge-transfer excitations. These states are found to cause multiple Auger decay processes upon resonant excitation. We identify several of these processes and determine their relative contribution to the Auger signal quantitatively. As our resPES data allow a quantitative analysis of these defect states, we determine the relative abundance of the PDOS in the VB and in CB and also the charge neutrality level. The anatase and rutile polymorphs of TiO2 are analyzed in the same way as the TiO2 ALD layer. The electronic properties of the TiO2ALD layer are compared with the anatase and rutile polymorphs of TiO2. In our comparative study, we find that ALD has its own characteristic electronic structure that is distinct from that of anatase and rutile. However, many details of the electronic structure are comparable and we benefit from our spectroscopic data and our careful analysis to find these differences. These can be attributed to a stronger hybridization of the O2p and Ti3d4s states for the ALD films when compared to the anatase and rutile polymorphs. KW - titanium dioxide (TiO2) KW - resonant photoemission spectroscopy (resPES) KW - defect states KW - partial density of states (pDOS) KW - charge neutrality level (CNL) Y1 - 2016 U6 - https://doi.org/10.1088/0022-3727/49/27/275304 SN - 0022-3727 SN - 1361-6463 VL - 49 IS - 27 SP - 275304-1 EP - 275304-17 ER - TY - CHAP A1 - Richter, Matthias A1 - Lichterman, Michael F. A1 - Hu, Shu A1 - Crumlin, Ethan J. A1 - Axnanda, Stephanus A1 - Favaro, Marco A1 - Drisdell, Walter S. A1 - Hussain, Zahid A1 - Brunschwig, Bruce S. A1 - Liu, Zhi A1 - Lewis, Nathan S. A1 - Lewerenz, Hans-Joachim T1 - Experimental Approach for Determining Semiconductor/liquid Junction Energetics by Operando Ambient Pressure X-ray Photoelectron Spectroscopy T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - The performance of a photoelectrochemical solar cell depends strongly on the electrochemical nature of the semiconductor/electrolyte junction [1]. Operando Ambient Pressure X-ray photoelectron spectroscopy investigation of semiconductor/liquid junctions provides quantitative understanding of the energy bands in these photoelectrochemical solar cells [2, 3, 4]. We demonstrate how OAP-XPS may be used to determine these relationships for semiconductor/liquid systems. The data can be analyzed to determine the energy relationship between the electronic energy bands in the semiconductor electrode and the redox levels in the solution. The major conditions for semiconductor-electrolyte contacts including accumulation, depletion, and Fermi-level pinning are observed, and the so-called flat-band energy can be determined. [1] Science 344 (2014) 1005; [2] Sci Rep 5 (2015) 9788; [3] Ener Sci 8 (2015) 2409; [4] J Electrochem Soc 162 (2016) H1 KW - in operando KW - ambient pressure spectroscopy KW - water splitting Y1 - 2016 UR - http://www.dpg-verhandlungen.de/year/2016/conference/regensburg/part/o/session/72/contribution/10?lang=en SP - S. 409 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Lichterman, Michael F. A1 - Richter, Matthias A1 - Hu, Shu A1 - Crumlin, Ethan J. A1 - Axnanda, Stephanus A1 - Favaro, Marco A1 - Drisdell, Walter S. A1 - Hussain, Zahid A1 - Brunschwig, Bruce S. A1 - Liu, Zhi A1 - Lewis, Nathan S. A1 - Lewerenz, Hans-Joachim T1 - Probing the TiO2/Liquid Interface of a Photoelectrochemical Cell by X-Ray Photoelectron Spectroscopy T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - Amorphous TiO2 coatings can stabilize semiconductor photoanodes such as Si, GaAs, and GaP that are otherwise unstable in aqueous media [1]. Using tender X-rays with their substantially increased inelastic mean free scattering length of photoelectrons and using the classical three-electrode potentiostatic arrangement allows one to follow of the influence of the applied potentials on the semiconductor electrode energetics such as band bending and band edge shifts directly [2, 3]. The observed shifts in binding energy with respect to the applied potential have directly revealed rectifying junction behavior on semiconducting samples. Accumulation, depletion and Fermi level pinning were observed. Additionally, the non-linear response of the core level binding energies to changes in the applied electrode potential has revealed the influence of defect-derived electronic states on the Galvani potential across the complete cell. [1] Science 344 (2014) 1005; [2] Sci Rep 5 (2015) 9788; [3] Ener & Env Sci 8 (2015) 2409 KW - X-Ray photoelectron spectroscopy KW - phototanodes KW - TiO2 passivation KW - water splitting Y1 - 2016 UR - http://www.dpg-verhandlungen.de/year/2016/conference/regensburg/part/o/session/82/contribution/1?lang=en SP - S. 414 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Haeberle, Jörg A1 - Richter, Matthias A1 - Schmeißer, Dieter A1 - Galazka, Zbigniew A1 - Janowitz, Christoph T1 - Resonant Photoemission at the O1s threshold to characterize In2O3 single crystals T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - We report on spectroscopic investigations on In2O3 single crystals. We focus on the detailed analysis of the O1s resonance profile by resonant photoelectron spectroscopy (resPES). From these we analyze the electronic structure and assign the O2p- and In5sp state to build the valence band and the conduction band in different contributions, respectively. This is deduced from constant final state spectra on the O-KLL-Auger along the O K-edge and In M4,5-edge and a comparison to the corresponding X-ray absorption spectroscopy data. We also identify several types of defects. A broad band of oxygen derived defects is identified in the valence band and extends throughout the gap. Small polarons are attributed to cause an anti-resonance in the constant initial states around the O1s threshold. In addition, an Auger decay separated by the O-KLL is present at O-K resonance and indicates the existence of localized charge transfer states which involves In5sp states. Finally, we are able to distinguish two different oxygen species from the resPES data. One corresponds to theintrinsic In2O3 structure and the other is a non-corresponding species. KW - resonant photoelectron spectroscopy KW - In2O3 Y1 - 2013 UR - http://www.dpg-verhandlungen.de/year/2013/conference/regensburg/part/mm/session/15/contribution/57?lang=de PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Richter, Matthias A1 - Schmeißer, Dieter T1 - The Co2p spin and oxidation state in Co-PI catalysts T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - The electronic structure of cobalt based catalysts used for photocatalytic water splitting in solar cells is analyzed using synchrotron radiation photoelectron spectroscopy. The catalyst films are prepared by electrochemical deposition. We employ a X-ray photoelectron spectroscopy study to analyze the Co2p and O1s core levels, absorption edges and valence bands. We discuss our resonant data in terms of the partial density of states of the valence and conduction band. We find a difference in the Co oxidation state as a function of film thickness (deposited charge). From the relative amount of Co, O, K and P we favor the molecular cobaltate cluster-like structure as the structural motif of the Co-PI catalyst. Further, at resonant PES at the Co2p edge we find the Co2p partial DOS to exhibit no sharp features next to the VBM, instead there is a broad emission at around 6eV below EFerrmi. The former are found in LiCoO2 and other Co-oxide systems with a Co3+ ground state. We attribute such sharp features to the low spin (LS) configuration of Co3+ and deduce that in the Co catalysts there is no evidence for the corresponding LS contributions. Our data prove the Co2+ ground state and demonstrate that it is exclusively in the Co3d7 high spin state in the pristine catalyst films. KW - X-Ray photoelectron spectroscopy KW - resonant photoemission spectroscopy KW - cobalt based catalyst KW - water splitting Y1 - 2013 UR - http://www.dpg-verhandlungen.de/year/2013/conference/regensburg/part/ds/session/35/contribution/9?lang=de PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Richter, Matthias A1 - Lichterman, Michael F. A1 - Hu, Shu A1 - Crumlin, Ethan J. A1 - Axnanda, Stephanus A1 - Favaro, Marco A1 - Drisdell, Walter S. A1 - Hussain, Zahid A1 - Brunschwig, Bruce S. A1 - Liu, Zhi A1 - Lewis, Nathan S. A1 - Lewerenz, Hans-Joachim T1 - An Electrochemical, resonant Photoemission and Ambient Pressure-X-ray Photoelectron Spectroscopic Investigation of Si/TiO2/Ni/Electrolyte Interfaces T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - Photoelectrochemical cells based on semiconductor-liquid interfaces provide a method of converting solar energy to electricity or fuels. Recently, we have demonstrated operational systems that involved stabilized semiconductor-liquid junctions [1]. The electrical and spectroscopic properties of the TiO2/Ni protection layer system have been investigated in contact with electrolyte solutions [2, 3, 4]. From the response of the photoelectron binding energies to variations in applied potential the energetics of the solid/electrolyte interface are elucidated. The degree of conductivity depended on the chemical state of the Ni on the TiO2 surface. The combinations of these techniques provide a powerful tool for the investigation of hybrid electrode/solution contacts. [1] Science 344 (2014) 1005; [2] Sci Rep 5 (2015) 9788; [3] Ener & Env Sci 8 (2015) 2409; [4] J Electrochem Soc 162 (2016) H1 KW - resonant photoelectron spectroscopy KW - ambient pressure spectroscopy KW - water splitting Y1 - 2016 UR - http://www.dpg-verhandlungen.de/year/2016/conference/regensburg/part/o/session/82/contribution/2?lang=en SP - S. 414 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Bilz, Ludwig A1 - Sudeck, Gorden A1 - Bucksch, Jens A1 - Klocke, Andreas A1 - Kolip, Petra A1 - Melzer, Wolfgang A1 - Ravens-Sieberer, Ulrike A1 - Richter, Matthias ED - Bilz, Ludwig ED - Sudeck, Gorden ED - Bucksch, Jens ED - Klocke, Andreas ED - Kolip, Petra ED - Melzer, Wolfgang ED - Ravens-Sieberer, Ulrike ED - Richter, Matthias T1 - Der vierte deutsche Jugendgesundheitssurvey „Health Behaviour in School-aged Children“ T2 - Schule und Gesundheit : Ergebnisse des WHO-Jugendgesundheitssurveys "Health behaviour in school-aged children" Y1 - 2016 SN - 978-3-7799-1991-9 SP - 7 EP - 15 PB - Beltz Juventa CY - Weinheim ER - TY - CHAP A1 - Bucksch, Jens A1 - Finne, Emily A1 - Gohres, Hannah A1 - Bilz, Ludwig A1 - Moor, Irene A1 - Richter, Matthias A1 - Kolip, Petra ED - Bilz, Ludwig ED - Sudeck, Gorden ED - Bucksch, Jens ED - Klocke, Andreas ED - Kolip, Petra ED - Melzer, Wolfgang ED - Ravens-Sieberer, Ulrike ED - Richter, Matthias T1 - Die Methodik des HBSC-Surveys 2013/14 T2 - Schule und Gesundheit : Ergebnisse des WHO-Jugendgesundheitssurveys "Health behaviour in school-aged children" Y1 - 2016 SN - 978-3-7799-1991-9 SP - 35 EP - 46 PB - Beltz Juventa CY - Weinheim ER -