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 - 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 - TY - GEN A1 - Lampert, Thomas A1 - Richter, Matthias A1 - Schreiber, Sven A1 - Spallek, Jacob A1 - Dragano, Nico T1 - Soziale Ungleichheit und Gesundheit. Stand und Perspektiven der sozialepidemiologischen Forschung in Deutschland T2 - Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz Y1 - 2016 U6 - https://doi.org/10.1007/s00103-015-2275-6 SN - 1436-9990 SN - 1437-1588 VL - 59 IS - 2 SP - 153 EP - 165 ER -