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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 21 to 27 of 27 (0.014 seconds)| 21 |
Heterogene Interdiffusion von nanokristallinen Cu/Co/Au-Schichten / Heterogenous interdiffusion of nanocrystalline Cu/Co/Au-layersLang, Christian 30 October 2001 (has links)
No description available.
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Structure and morphology of ultrathin iron and iron oxide films on Ag(001)Bruns, Daniel 21 November 2012 (has links)
This work investigates the initial growth of iron and iron oxides on Ag(001).
Surface structure and morphology of both post deposition annealed Fe films (in UHV and
O2 atmosphere) as well as reactive grown iron oxide films will be analyzed in detail by low energy electron diffraction (LEED) and scanning tunneling microscopy (STM). The stoichiometry at the surface of the iron oxide films will be determined by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The main focus of this work is to shed light on the question whether the growth of iron oxide films on Ag(001) is accompanied by the formation of strain reducing dislocation
networks, or superstructures as found for other metal substrates in former studies. Here, we will distinguish between Fe films which were post deposition annealed in
a thin O2 atmosphere and reactively grown iron oxide films.
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Mutual interactions of femtosecond pulses and transient gratings in nonlinear optical spectroscopyNolte, Stefan 16 November 2018 (has links)
This work is dedicated to a comprehensive experimental study on the interaction of femtosecond laser pulses with the nonlinear optical medium lithium niobate. The nonlinear optical response in the nanosecond regime was already studied extensively with a variety of techniques, whereas femtosecond pulses were mainly used in transient absorption or transient grating experiments. Naturally, the temporal resolution of these measurements depends on the pulse duration, however, dynamics during the pulse excitation were barely investigated.
The motivation of this work is to widen the limits of femtosecond spectroscopy, not only to temporally resolve faster nonlinear optical processes, but further to show a sensitivity to other coupling mechanisms between the pulses and the material. Especially, the role of transient, dynamic holographic gratings is investigated with a careful determination of the pulse duration, bandwidth and frequency chirp. A basis of this work is established in the first part by studying the material response via light-induced absorption before focusing on the main topic, the pulse interaction with elementary (holographic) gratings, both self-induced and static, in the second part. By this detailed study, several features of femtosecond laser pulses, holographic gratings and the ultrafast material response can be revealed: (i) grating recording is feasible even with pulses of different frequencies, provided that their pulse duration is sufficiently short, (ii) grating based pulse coupling causes a pronounced energy transfer even in a common pump-probe setup for transient absorption measurements with (non-)degenerated frequencies, (iii) beyond expectation, oscillations in the phonon frequency range become apparent in different measurements. The presented results point towards appropriate future experiments to obtain a more consistent, microscopic model for the ultrafast response of the crystal, involving the interplay between photo-generated polarons, self-induced gratings, and phonons.
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Hochauflösende gamma-Diffraktometrie zur Untersuchung der Ferroelektrischen Lock-in Phasenumwandlung in Rb<sub>2</sub>ZnCl<sub>4</sub> / High resolution gamma-diffractometry for the Study of the ferroelectric lock-in phase transition in Rb<sub>2</sub>ZnCl<sub>4</sub>Elisbihani, Khalid 18 June 2002 (has links)
No description available.
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Glättungsmechanismen beim Ionenbeschuss rauer amorpher Oberflächen / Smoothing mechanisms due to ion bombardment of rough amorphous surfacesVauth, Sebastian 11 October 2007 (has links)
No description available.
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Ab-initio-Untersuchungen von Oberflächen- und BulksystemenGreuling, Andreas 21 December 2010 (has links)
In dieser Arbeit setzen wir ab-initio-Methoden zur Untersuchung einiger Oberflächensysteme
und eines Bulksystems ein. Im Wesentlichen greifen wir hierbei auf die Dichtefunktionaltheorie
(DFT) und die GW-Approximation (GWA) im Rahmen der Vielteilchenstörungstheorie
zurück. Wir nutzen diese Methoden um die Adsorption von TMA auf der Rutil TiO2-Oberfläche zu untersuchen, optische Spektren von TiO2 zu berechnen und um die Adsorption von [7]-HCA auf der Calcit(10-14)-Oberfläche zu verstehen. Weiterhin beschäftigen wir uns intensiv mit PTCDA auf Ag(111), welches mit einer chemisch kontaktierten STM-Spitze manipuliert wird.
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Lanthanide Doped Wide Band Gap Semiconductors: Intra-4f Luminescence and Lattice Location Studies / Lanthanid-dotierte Halbleiter mit großer Bandlücke: Intra-4f Lumineszenz- und GitterplatzuntersuchungenVetter, Ulrich 15 July 2003 (has links)
No description available.
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