Technikethik als Risikoethik. Ansätze einer sozialethischen Risikobeurteilung

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Die Zeit der Gesellschaft – Sozialethik als Zeitdiagnose

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Gut in der Zeit? Beschleunigung - Synchronie - Zeitverschiebung

Der Grad technischer und sozialer Fortschritte wird in modernen Gesellschaften an dem Tempo gemessen, mit dem sich erhoffte Verbesserungen einstellen. Daseins-Optimierungen sind umso besser, je schneller sie erzielt werden. Die Zukunft rückt dabei immer rascher an die Gegenwart heran, aber ebenso verringert sich die Geltungs- und Aktualitätsdauer des Gegenwärtigen. Wartezeiten verkürzen sich im selben Maße wie Verweilzeiten. Museen und Archive, Datenbanken und Mediatheken halten das Vergangene dauerhaft präsent. Bewegen wir uns auf eine „Instantkultur“ zu, in der Künftiges, Gegenwärtiges und Vergangenes keinen klar unterscheidbaren Zeitzonen mehr angehören? Besteht im Zeitalter der Beschleunigung eine kulturelle Schlüsselqualifikation in der Synchronisierung alles Zeitlichen? Welche Nebenwirkungen haben diese „Zeitverschiebungen“? EnglishHans-Joachim Höhn: Making Good Time? Acceleration – Synchrony – Time Lag In modern societies the degree of technical and social progress is measured according to the pace with which hoped-for improvements materialize. Existential optimizations are all for the better, depending on how quickly they can be realized. The future is thereby drawn ever more quickly towards the present while, correspondingly, the duration of both validity and actuality are decreased. Waiting- times are shortened to the same degree as staying-times. Museums and archives, databases and media libraries all keep the past lastingly ever-present. Are we moving towards an “instant culture”, in which future, present and past events no longer belong to clear and distinct time-zones? In the age of acceleration, does a cultural “key skill” exist, with regard to the synchronization of all that is temporal? What side-effects do these time differences have?

Handlungstheorie und Sozialethik. Reflexionsstufen einer Ethik sozialen Handelns

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Materials for light-induced water splitting: In situ controlled surface preparation of GaPN epilayers grown lattice-matched on Si(100)

Energy storage is a key challenge in solar-driven renewable energy conversion. We promote a photochemical diode based on dilute nitride GaPN grown lattice-matched on Si(100), which could reach both high photovoltaic efficiencies and evolve hydrogen directly without external bias. Homoepitaxial GaP(100) surface preparation was shown to have a significant impact on the semiconductor-water interface formation. Here, we grow a thin, pseudomorphic GaP nucleation buffer on almost single-domain Si(100) prior to GaPN growth and compare the GaP_(0.98)N_(0.02)/Si(100) surface preparation to established P- and Ga-rich surfaces of GaP/Si(100). We apply reflection anisotropy spectroscopy to study the surface preparation of GaP_(0.98)N_(0.02) in situ in vapor phase epitaxy ambient and benchmark the signals to low energy electron diffraction, photoelectron spectroscopy, and x-ray diffraction. While the preparation of the Ga-rich surface is hardly influenced by the presence of the nitrogen precursor 1,1-dimethylhydrazine (UDMH), we find that stabilization with UDMH after growth hinders well-defined formation of the V-rich GaP_(0.98)N_(0.02)/Si(100) surface. Additional features in the reflection anisotropy spectra are suggested to be related to nitrogen incorporation in the GaP bulk

Water-induced modifications of GaP(100) and InP(100) surfaces studied by photoelectron spectroscopy and reflection anisotropy spectroscopy

In this work, we investigate the initial interaction of water and oxygen with different surface reconstructions of GaP(100) applying photoelectron spectroscopy, low-energy electron diffraction, and reflection anisotropy spectroscopy. Surfaces were prepared by metal-organic vapour phase epitaxy, transferred to ultra-high vacuum, and exposed to oxygen or water vapour at room temperature. The (2 4) reconstructed, Ga-rich surface is more sensitive and reactive to adsorption, bearing a less ordered surface reconstruction upon exposure and indicating a mixture of dissociative and molecular water adsorption. The p(2 2)=c(4 2) P-rich surface, on the other hand, is less reactive, but shows a new surface symmetry after water adsorption. Correlating findings of photoelectron spectroscopy with reflection anisotropy spectroscopy could pave the way towards optical in-situ monitoring of electrochemical surface modifications with reflection anisotropy spectroscopy

The interface of GaP(100) and H2O studied by photoemission and reflection anisotropy spectroscopy

We study the initial interaction of adsorbed H2O with P-rich and Ga-rich GaP(100) surfaces. Atomically well defined surfaces are prepared by metal-organic vapour phase epitaxy and transferred contamination-free to ultra-high vacuum, where water is adsorbed at room temperature. Finally, the surfaces are annealed in vapour phase ambient. During all steps, the impact on the surface properties is monitored with in situ reflection anisotropy spectroscopy (RAS). Photoelectron spectroscopy and low-energy electron diffraction are applied for further in system studies. After exposure up to saturation of the RA spectra, the Ga-rich (2 × 4) surface reconstruction exhibits a sub-monolayer coverage in form of a mixture of molecularly and dissociatively adsorbed water. For the p(2 × 2)/c(4 × 2) P-rich surface reconstruction, a new c(2 × 2) superstructure forms upon adsorption and the uptake of adsorbate is significantly reduced when compared to the Ga-rich surface. Our findings show that microscopic surface reconstructions of GaP(100) greatly impact the mechanism of initial interface formation with water, which could benefit the design of e.g. photoelectrochemical water splitting devices

The interface of GaP(100) and H_2O studied by photoemission and reflection anisotropy spectroscopy

We study the initial interaction of adsorbed H_2O with P-rich and Ga-rich GaP(100) surfaces. Atomically well defined surfaces are prepared by metal-organic vapour phase epitaxy and transferred contamination-free to ultra-high vacuum, where water is adsorbed at room temperature. Finally, the surfaces are annealed in vapour phase ambient. During all steps, the impact on the surface properties is monitored with in situ reflection anisotropy spectroscopy (RAS). Photoelectron spectroscopy and low-energy electron diffraction are applied for further in system studies. After exposure up to saturation of the RA spectra, the Ga-rich (2 × 4) surface reconstruction exhibits a sub-monolayer coverage in form of a mixture of molecularly and dissociatively adsorbed water. For the p(2 × 2)/c(4 × 2) P-rich surface reconstruction, a new c(2 × 2) superstructure forms upon adsorption and the uptake of adsorbate is significantly reduced when compared to the Ga-rich surface. Our findings show that microscopic surface reconstructions of GaP(100) greatly impact the mechanism of initial interface formation with water, which could benefit the design of e.g. photoelectrochemical water splitting devices