Self-organization is a hot topic as it has the potential to create surface patterns on the nanoscale avoiding cost-intensive top-down approaches. Although chemists have promising results in this area, ion irradiation can create self-organized surface patterns in a more controlled manner. Different regimes of pattern formation under ion irradiation were described so far by 2D models. Here, two new regimes have been studied experimentally, which require modeling in 3D: subsurface point defect kinetics as well as ion impact-induced melt pool formation. This thesis deals with self-organized pattern formation on Ge and Si surfaces under normal incidence irradiation with heavy monatomic and polyatomic ions of energies up to several tens of keV. Irradiation has been performed using liquid metal ion sources in a focused ion beam facility with mass-separation as well as by conventional broad beam ion implantation. Irradiated samples have been analyzed mainly by scanning electron microscopy. Related to the specific irradiation conditions, investigation and discussion of pattern formation has been divided into two parts: (i) formation of Ge morphologies due to point defect kinetics and (ii) formation of Ge and Si morphologies due to melt pool dynamics. Point defect kinetics dominates pattern formation on Ge under irradiation with monatomic ions at room temperature. Irradiation of Ge with Bi and Ge ions at fluences up to 10^17 cm^(-2) has been performed. Comprehensive studies show for the first time that morphologies change from flat surfaces over hole to nanoporous, sponge-like patterns with increasing ion energy. This study is consistent with former irradiations of Ge with a few ion energies. Based on my studies, a consistent, qualitative 3D model of morphology evolution has been developed, which attributes the ion energy dependency of the surface morphology to the depth dependency of point defect creation and relaxation. This model has been proven by atomistic computer experiments, which reproduce the patterns found in real irradiation experiments. At extremely high energy densities deposited by very heavy ions another mechanism dominates pattern formation. The formation of Ge and Si dot patterns by very heavy, monatomic and polyatomic Bi ion irradiation has been studied in detail for the first time. So far, this formation of pronounced dot pattern cannot be explained by any model. Comprehensive, experimental studies have shown that pattern formation on Ge is related to extremely high energy densities deposited by each polyatomic ion locally. The simultaneous impact of several atoms leads to local energy densities sufficient to cause local melting. Heating of Ge substrates under ion irradiation increases the achievable energy density in the collision cascade substantially. This prediction has been confirmed experimentally: it has been found that the threshold for nanomelting can be lowered by substrate heating, which allows pattern formation also under heavy, monatomic ion irradiation. Extensive studies of monatomic Bi irradiation of heated Ge have shown that morphologies change from sponge-like over highly regular dot patterns to smooth surfaces with increasing substrate temperature. The change from sponge-like to dot pattern is correlated to the melting of the ion collision cascade volume, with energy densities sufficient for melt pool formation at the surface. The model of pattern formation on Ge due to extremely high deposited energy densities is not specific to a single element. Therefore, Si has been studied too. Dot patterns have been found for polyatomic Bi ion irradiation of hot Si, which creates sufficiently high energy densities to allow ion impact-induced melt pool formation. This proves that pattern formation by melt pool formation is a novel, general pattern formation mechanism. Using molecular dynamics simulations of project partners, the correlation between dot patterning and ion impact-induced melt pool formation has been proven. The driving force for dot pattern formation due to high deposited energy densities has been identified and approximated in a first continuum description.

Using a cryogenic linear 22-pole rf ion trap, rate coefficients for H/D exchange reactions of OH− with D2 (1) and OD− with H2 (2) have been measured at temperatures between 11 K and 300 K with normal hydrogen. Below 60 K, we obtained k1 = 5.5 × 10−10 cm3 s−1 for the exoergic reaction (1). Upon increasing the temperature above 60 K, the data decrease with a power law, k1(T) [similar] T−2.7, reaching ≈1 × 10−10 cm3 s−1 at 200 K. This observation is tentatively explained with a decrease of the lifetime of the intermediate complex as well as with the assumption that scrambling of the three hydrogen atoms is restricted by the topology of the potential energy surface. The rate coefficient for the endoergic reaction (2) increases with temperature from 12 K up to 300 K, following the Arrhenius equation, k2 = 7.5 × 10−11 exp(−92 K/T) cm3 s−1 over two orders of magnitude. The fitted activation energy, EA-Exp = 7.9 meV, is in perfect accordance with the endothermicity of 24.0 meV, if one accounts for the thermal population of the rotational states of both reactants. The low mean activation energy in comparison with the enthalpy change in the reaction is mainly due to the rotational energy of 14.7 meV contributed by ortho-H2 (J = 1). Nonetheless, one should not ignore the reactivity of pure para-H2 because, according to our model, it already reaches 43% of that of ortho-H2 at 100 K. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

This paper presents a homogeneous system of magnetic colloidal particles that self-assembles via two structural patterns of different symmetry. Based on a qualitative comparison between a real magnetic particles system, analytical calculations and molecular dynamics simulations, it is shown that bistability can be achieved by a proper tailoring of an anisotropic magnetization distribution inside the particles. The presented bistability opens new possibilities to form two-dimensionally extended and flexible structures where the connectivity between the particles can be changed in vivo. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

In the present work, the plasma repair for damaged ultra-low-k (ULK) materials, newly developed at the Fraunhofer ENAS, is studied with density functional theory (DFT) and molecular dynamic (MD) methods to obtain new insights into this repair mechanism. The ULK materials owe their low dielectric constant (k-value) to the insertion of k-value lowering methyl groups. During the manufacturing process, the ULK materials are damaged and their k-values increase due to the adsorbtion of hydroxyl groups (OH-damage) and hydrogen atoms (H-damage) that replaced themethyl groups. The first investigation point is the creation of repair fragments. For this purpose the silylation molecules bis(dimethylamino)-dimethylsilane (DMADMS) and octamethylcyclotetrasiloxane (OMCTS) are fragmented. Here, only fragmentation reactions that lead to repair fragments that contain one silicon atom and at least one methyl group were considered. It is shown that the repair fragments that contain three methyl groups are preferred, especially in a methyl rich atmosphere. The effectivity of the obtained repair fragments to cure an OH- and H-damage are investigated with two model systems. The first system consists of an assortment of small ULK-fragments, which is used to scan through the wide array of possible repair reactions. The second system is a silicon oxide cluster that investigates whether the presence of a cluster influences the reaction energies. In both model systems, repair fragments that contain three methyl groups or two oxygen atoms are found to be most effective. Finally, the quantum chemical results are compared to experimental findings to get deeper insight into the repair process.:1. Introduction 2. Theoretical Background 2.1. Ultra-low-k Materials 2.1.1. Definition, Usage and Challenges 2.1.2. k-Restore 2.2. Reaction Theory 2.2.1. Reaction Process 2.2.2. Thermal Influence 3. Computational Methods 3.1. Overview 3.2. Density Functional Theory 3.2.1. Theoretical Background 3.2.1.1. The Schrödinger Equation and the Variational Principle 3.2.1.2. From the Electron Density to the Kohn-Sham Approach 3.2.1.3. Exchange-Correlation Functionals and Basis Sets 3.2.2. Used Program Packages 3.3. ReaxFF 3.3.1. Theoretical Background 3.3.2. Used Program Packages 4. Model System 4.1. Damaged ULK Materials 4.1.1. ULK-Fragments 4.1.2. Silicon Oxide Cluster 4.2. Repair Fragments 4.2.1. Overview 4.2.2. Fragmentation of DMADMS 4.2.3. Fragmentation of OMCTS 4.2.4. Continuing Reactions 5. Results and Discussion 5.1. Reactions between Repair Fragments and ULK-Fragments 5.1.1. Repair of OH-damages 5.1.2. Repair of H-damages 5.1.3. Selected Repair Reactions with Gaussian 5.2. Reactions Between Repair Fragments and Silicon Oxide Cluster 5.2.1. Comparison Between ULK-Fragments and Silicon Oxide Cluster 5.2.2. Comparability of DFT and MD Results 5.3. Comparison with Experimental Results 6. Summary and Outlook A. Appendix A.1. Temperature Influence . A.1.1. Temperature Influence on the DMADMS Fragmentation in Dmol3 A.1.2. Temperature Influence on the OMCTS Fragmentation in Dmol3 . A.2. Tests A.2.1. DMADMS Fragmentation with Gaussian A.2.2. G2 Test Set A.2.3. Calculation Time of the Silicon Oxide Cluster in Dmol3 A.3. Error Analysis A.3.1. Basis Set Superposition Error in Dmol3 A.3.2. Dispersion Correction A.4. Illustration of Defects A.5. Bookmark

Die Charakterisierung hochdimensionaler Systeme mit Lyapunov-Instabilität wird durch das Lyapunov-Spektrum und die zugehörigen Lyapunov-Vektoren ermöglicht. Für eine Vielzahl von derartigen Systemen (Coupled-Map-Lattices, Hartkugel-Systeme, Systeme mit ausgedehnten Potentialen ...) konnte durch die Untersuchung der Lyapunov-Vektoren die Existenz von hydrodynamischen Lyapunov-Moden nachgewiesen werden. Diese kollektiven Anregungen zeigen sich in Lyapunov-Vektoren, deren Lyapunov-Exponenten dem Betrage nach am kleinsten sind. Da Lyapunov-Exponenten charakteristische Zeitskalen innerhalb der Systeme repräsentieren, ist durch die Lyapunov-Moden eine Untersuchung des Langzeitverhaltens möglich. In dieser Arbeit werden die hydrodynamischen Lyapunov-Moden durch Molekulardynamiksimulationen von mehrkomponentigen Lennard-Jones-Flüssigkeiten untersucht. Die Charakterisierung der Lyapunov-Moden zeigt im weiteren eine Ähnlichkeit zu Dispersionsrelationen von Phononen.

The combination of modern self-assembly techniques with well-established top-down processing methods pioneered in the electronics industry is paving the way for increasingly sophisticated devices in the future[1]. Nanomembranes, made from a variety of materials, can provide the necessary framework for a diverse range of device structures incorporating wrinkling, buckling, folding, and rolling of thin films[2, 3]. Over the past decade, an elegant symbiosis of bottom-up and top-down methods has been developed, allowing the fabrica- tion of hybrid layer systems via the controlled release and rearrangement of inherently strained layers [4]. Self-assembled rolled-up structures[4, 5] have become increasingly at- tractive in a number of fields including micro/nano uidics[6], optics[7](including metama- terial optical fibers[8]), Lab on a Chip applications[9], and micro- and nanoelectronics[10]. The use of such structures for microelectronic applications has been driven by the versatility in contacting geometries and the abundance of material combinations that these devices offer. By allowing devices to expand in the third dimension, certain obstacles that inhibit 2D structuring can be overcome in elegant ways. Similarly, recent progress in nanostructured superconducting electronic structures has been receiving increased attention[11]. The advancement of such devices has been mo- tivated by their use in quantum computation[12], high sensitivity radiation sensors[13], precision voltage standards[14] and superconducting spintronics[15] to name a few. Combining semiconductor with superconductor materials to create new hybrid geometries is advantageous because it adds the functionalities of the semiconductor, including high charge carrier mobilities, gating possibilities, and refined processing technologies. The main focus of the work presented in this thesis is the development of new methods for controlling strain behavior and its applications toward novel semiconduc- tor/superconductor heterostructures based on nanomembranes. More specifically, the goal is to integrate inherently strained semiconductor layer structures with superconducting materials to create innovative electronic devices by the controlled releasing and rearrangement of thin films. By rolling up pre-patterned semiconductor/superconductor layers, device geometries have been realized that are not feasible using any other technique. In this way, superconducting hybrid junctions, or Josephson junctions, have been created and their basic properties investigated. The Josephson effect, and junctions displaying this quantum coherent behavior, have found many essential uses in diverse areas of science and technology. Many research groups around the world are involved in finding new materials and fabrication methods to tune the properties and structure of such Josephson devices further[11]. The inclusion of semi- conductors, for example, allows for a greater control of the charge carrier density within the junction area, thus allowing for "transistor-like" behavior in these superconducting devices. By rolling up the superconductor contacts using a strained semiconductor as scaffolding, the fabrication of hybrid nano-junctions is simplified drastically, removing the need for complicated processing steps such as electron-beam or nano-imprint lithography. Furthermore, the technique allows many nanometer-sized devices to be created in parallel on a single chip which has the advantage that it can be scaled up to full-wafer processing. First, post-growth processing techniques of epitaxial layers are developed in order to extend the control of hybrid device fabrication. Here, three unique concepts for controlling the rolling behavior of strained semiconductor nanomembranes are presented. First an optical method for inhibiting the rolling of the strained layers is described. Next, a selective etching method for destroying the inherent strain within the semiconductor layer is introduced. Finally, a method by which the strain gradient across a trilayer stack is altered in situ during rolling is presented. Next, the fabrication of a hybrid nanomembrane-based superconducting device is presented. Various experimental details of the fabrication process are analyzed, and the electronic properties of the completed device are investigated. The devices created here highlight the fabrication process in which nanometer-sized structures are created using self-assembly techniques and standard microelectronics fabrication methods, presenting a new method to circumvent more complicated processing techniques. References [1] G. M. Whitesides and B. Grzybowski. Self-assembly at all scales. Science 295, 2418{2421 (2002). [2] Y. G. Sun, W. M. Choi, H. Q. Jiang, Y. G. Y. Huang and J. A. Rogers. Controlled buckling of semiconductor nanoribbons for stretchable electronics. Nature Nanotechnology 1, 201{207 (2006). [3] O. G. Schmidt and K. Eberl. Nanotechnology - Thin solid films roll up into nanotubes. Nature 410, 168 (2001). [4] O. G. Schmidt, C. Deneke, Y. Nakamura, R. Zapf-Gottwick, C. Mller and N. Y. Jin-Phillipp. Nanotechnology { Bottom-up meets top-down. Advanced Solid State Physics 42, 231 (2002). [5] V. Ya. Prinz, V. A. Seleznev, A. K. Gutakovsky, A. V. Chehovskiy, V. V. Preobrazhenskii, M. A. Putyato and T. A. Gavrilova. Free-standing and overgrown InGaAs/GaAs nanotubes, nanohelices and their arrays. Physica E 6, 828 (2000). [6] D. J. Thurmer, C. Deneke, Y. F. Mei and O. G. Schmidt. Process integration of microtubes for uidic applications. Applied Physics Letters 89, 223507 (2006). [7] R. Songmuang, A. Rastelli, S. Mendach and O. G. Schmidt. SiOx/Si radial superlattices and microtube optical ring resonators. Applied Physics Letters 90, 091905 (2007). [8] E. J. Smith, Z. W. Liu, Y. F. Mei and O. G. Schmidt. Combined surface plasmon and classical waveguiding through metamaterial fiber design. Nano Letters 10, 1{5 (2010). [9] G. S. Huang, Y. F. Mei, D. J. Thurmer, E. Coric and O. G. Schmidt. Rolled-up transparent microtubes as two-dimensionally confined culture scaffolds of individual yeast cells. Lab on a Chip 9, 263{268 (2009). [10] C. C. B. Bufon, J. D. C. Gonzalez, D. J. Thurmer, D. Grimm, M. Bauer and O. G. Schmidt. Self-assembled ultra-compact energy storage elements based on hybrid nanomembranes. Nano Letters 10, 2506{2510 (2010). [11] G. Katsaros, P. Spathis, M. Stoffel, F. Fournel, M. Mongillo, V. Bouchiat, F. Lefloch, A. Rastelli, O. G. Schmidt and S. De Franceschi. Hybrid superconductor-semiconductor devices made from self-assembled SiGe nanocrystals on silicon. Nature Nanotechnology 5, 458{464 (2010). [12] Y. J. Doh, J. A. van Dam, A. L. Roest, E. P. A. M. Bakkers, L. P. Kouwenhoven and S. De Franceschi. Tunable supercurrent through semiconductor nanowires. Science 309, 272{275 (2005). [13] F. Giazotto, T. T. Heikkila, G. P. Pepe, P. Helisto, A. Luukanen and J. P. Pekola. Ultrasensitive proximity Josephson sensor with kinetic inductance readout. Applied Physics Letters 92, 162507 (2008). [14] S. P. Benz. Superconductor-normal-superconductor junctions for programmable voltage standards. Applied Physics Letters 67, 2714{2716 (1995). [15] Y. C. Tao and J. G. Hu. Superconducting spintronics: Spin-polarized transport in superconducting junctions with ferromagnetic semiconducting contact. Journal of Applied Physics 107, 041101 (2010).

Four cluster models for a copper(I)oxide (111) surface have been designed, of which three were studied with respect to their applicability in density functional calculations in the general gradient approximation. Formic acid adsorption on these systems was modelled and yielded four different adsorption structures, of which two were found to have a high adsorption energy. The energetically most favourable adsorption structure was further investigated with respect to its decomposition and a few reactions with adsorbed H and OH species using synchronous transit methods to estimate reaction barriers and single point energy calculations for the reaction energy.:1 Introduction 1.1 Preliminary Work 1.2 Known Reactions and Issues 1.3 Overview of Reactions and Species involved in Formic Acid Decomposition 2 Theoretical Background 2.1 The Schrödinger-Equation 2.2 Density Functional Theory 2.3 Exchange-Correlation Functionals 2.4 The Self-Consistent-Field Procedure 2.5 Geometry Optimization and Transition State Searches 2.6 Kinetics 3 Computational Details 3.1 Synchronous Transit Schemes 3.2 Transition State Searches using Eigenvector Following 4 Model System 5 Results and Discussion 5.1 Geometry of the Cu2O cluster structures 5.2 Adsorption of formic acid 5.3 Decomposition and Reaction Paths 5.3.1 Vibrational Analysis of the adsorbed Formic Acid Molecule 5.3.2 Reaction Modelling using Linear Synchronous Transit 5.3.3 Transition State Searches using Eigenvector Following 6 Summary and Outlook

In dieser Dissertation werden das Anregungsspektrum und das Phasendiagramm wechselwirkender Fermi- und Bosegase untersucht. Zu diesem Zweck wird eine neuartige renormierte Kadanoff-Martin-Näherung vorgestellt, die Selbstwechselwirkung von Teilchen vermeidet und somit eine einheitliche Beschreibung sowohl der normalen als auch der kondensierten Phase ermöglicht. Für Fermionen findet man den BCS-Zustand, benannt nach Bardeen, Cooper und Schrieffer, welcher entscheidend ist für das Phänomen der Supraleitung. Charakteristisch für diesen Zustand ist eine Energielücke im Anregungsspektrum an der Fermi-Energie. Weiterhin tritt für Bosonen eine Bose-Einstein-Kondensation (BEC) auf, bei der das Anregungsspektrum für kleine Impulse linear ist. Letzteres führt zum Phänomen der Suprafluidität. Über die bereits bekannten Phänomene hinaus findet man eine dem BCS-Zustand ähnliche Kondensation von Zweiteilchenbindungszuständen, sowohl für Fermionen als auch für Bosonen. Für Fermionen tritt ein Übergang zwischen der Kondensation von Bindungszuständen und dem BCS-Zustand auf, der sogenannte BEC-BCS-Übergang. Die Untersuchung der Zustandsgleichung zeigt, dass im Gegensatz zu Fermi-Gasen und Bose-Gasen mit abstoßender Wechselwirkung Bose-Gase mit anziehender Wechselwirkung zu einer Flüssigkeit kondensieren oder sich verfestigen, bevor es zur Kondensation von Bindungszuständen oder zur Bose-Einstein-Kondensation kommt. Daher können diese Phänomene voraussichtlich nicht in der Gasphase beobachtet werden. Zusammenfassend lässt sich sagen, dass das vorgestellte Näherungsverfahren sehr gut geeignet ist, die erwähnten Phänomene im Zusammenhang mit der Bose-Einstein-Kondensation zu beschreiben.

Indirekte Halbleiter, wie beispielsweise Silizium, zählen bei technischen Anwendungen zu den wichtigsten halbleitenden Materialien. Die indirekte Bandstruktur führt jedoch dazu, dass diese Materialien schlechte Lichtemitter sind. Die theoretische Beschreibung der optischen Eigenschaften dieser Materialien wurde in früheren Betrachtungen über phänomenologische Ansätze verfolgt. In dieser Arbeit wird eine mikroskopische Theorie, basierend auf den Heisenberg-Bewegungsgleichungen, entwickelt, um die Prozesse im Bereich der indirekten Energielücke zu beschreiben. Nach Herleitung der relevanten Gleichungen wird im ersten Anwendungskapitel die Absorption und optische Verstärkung im thermischen Gleichgewicht diskutiert. Bei der Diskussion wird insbesondere auf den Unterschied zu direkten Halbleitern eingegangen. Es zeigt sich, dass sich die optische Verstärkung in indirekten Halbleitern fundamental von denen in direkten unterscheidet. Im Gegensatz zum direkten Halbleiter kann die maximale optische Verstärkung eines indirekten Übergangs die maximale Absorption um Größenordnungen übertreffen. Im zweiten Anwendungsteil werden Nichtgleichgewichtsphänomene diskutiert. Durch starke optische Anregung kann eine hohe Elektronenkonzentration am Gamma-Punkt erzeugt werden. Da das globale Bandstrukturminimum aber am Rand der Brillouinzone liegt, verweilen die Elektronen nicht lange dort, sondern streuen in das Leitungsbandminimum. Dieser Prozess der sogenannten Intervalley-Streuung wird im Hinblick auf Gedächtniseffekte diskutiert. Nach dem Streuprozess der Elektronen besitzt das System eine Überschussenergie, die sich in einem Aufheizen der Ladungsträger zeigt. Das zweite Nichtgleichgewichtsphänomen ist das Abkühlen des Lochsystems, welches aufgrund der Trennung der Elektronen und Löcher in indirekten Halbleiter auch im Experiment getrennt untersucht werden kann. Mithilfe eines Experiment-Theorie-Vergleichs wird ein schneller Elektron-Loch-Streuprozess nachgewiesen, der dazu führt, dass in indirekten Halbleitern das Thermalisieren und Equilibrieren der Elektronen und Löcher auf der gleichen Zeitskala stattfindet.

In the thesis CuPc thin films were investigated by (in situ) SE and RAS, which are employed to determine the out-of-plane and in-plane optical anisotropy and molecular orientation, respectively. CuPc is a promising candidate of organic semiconductors used in organic field effect transistors, organic light emitting diodes and organic solar cells. Vicinal Si(111) substrates are interesting due to the in-plane anisotropy caused by the steps and terraces on the surface. The strength of in-plane anisotropy of vicinal Si(111) is dependent on the offcut angle. The influence of offcut angle on out-of-plane and in-plane molecular orientation in CuPc thin films is explored. The in situ investigation of CuPc films suggests that structural changes occur during film growth. In addition, two different surface modification layers were utilized to examine the effect on CuPc molecular orientation: OTS monolayer with upright standing molecules and PTCDA layers with flat lying molecules. Metal-organic interface plays an important role in organic electronic devices. In-CuPc is chosen to be an example system investigated employing in situ SE and RAS. When In was thermally evaporated onto CuPc film, In atoms firstly diffuse into the CuPc film underneath and then aggregate to form clusters on top. Hafnium dioxide (HfO2) is currently a hot topic to replace the conventionally used SiO2 as gate dielectrics in order to minimize leakage current when further scaling down microelectronic devices. Since HfO2 films are often crystalline, in order to obtain amorphous films which are beneficial to minimize leakage current, aluminum oxide (Al2O3) (k value: 9) which stays amorphous at much higher temperatures are combined to overcome this difficulty. Two series of ultra-thin samples were deposited by atomic layer deposition: mixed layers HfxAl1-xOz and bilayers HfO2 on Al2O3. Optical constants and bandgap are determined using SE in the energy range of 0.7-10 eV. It is found that the (effective) optical bandgap of both mixed layer and bilayer structures can be tuned by the film composition. Aging effect of high-k films was observed after storage of samples in air for two months, which is attributed to further oxidation of the dielectric films caused by the oxygen diffusion from ambient air to high-k films. / In dieser Arbeit werden dünne Schichten aus Kupferphthalozyanin (CuPc) mittels spektroskopischer (in-situ) Ellipsometrie (SE) und (in-situ) Reflektions-Anisotropie-Spektroskopie (RAS) untersucht, um die optische Anisotropie in einer Ebene parallel und senkrecht zur Schichtoberfläche und die molekulare Orientierung zu bestimmen. CuPc ist ein aussichtsreicher Kandidat als organischer Halbleiter in organischen Feldeffekt-Transistoren, organischen Leuchtdioden und organischen Solarzellen. Vizinale Si(111)-Substrate sind wegen der Anisotropie in der Substratebene interessant, die durch die Treppen und Terrassen auf der Oberfläche verursacht wird. Die Stärke der Anisotropie der vizinalen Si(111)-Oberfläche ist vom Schnittwinkel (Offcut) abhängig. Es wird der Einfluss des Offcut-Winkels auf die molekulare Orientierung in dünnen CuPc-Schichten parallel und senkrecht zur Substratoberfläche untersucht. Die in-situ Untersuchungen von CuPc-Schichten weisen darauf hin, dass strukturelle Veränderungen beim Wachstum auftreten. Darüber hinaus wurden zwei unterschiedliche Oberflächenmodifizierungsschichten, um deren Wirkung auf die molekulare Orientierung von CuPc zu untersuchen, verwendet: eine OTS-Monoschicht mit aufrecht stehenden Molekülen und PTCDA-Schichten mit flach liegenden Molekülen. Metall-organische Grenzflächen spielen eine wichtige Rolle in organischen elektronischen Bauelementen. In-CuPc wird als Beispiel für ein Metall-organisches System durch in-situ SE und RAS untersucht. Wenn In thermisch auf eine CuPc-Schicht aufgedampft wird, diffundieren In-Atome zunächst in die darunterliegende CuPc-Schicht und bilden dann Cluster auf der Schicht. Hafniumdioxid (HfO2) ist ein heißer Kandidat für das Ersetzen des herkömmlich als Gate-Dielektrikum verwendeten SiO2 mit dem Ziel, die Leckströme bei der weiteren Verkleinerung mikroelektronischer Bauelemente zu minimieren. Um amorphe Schichten, die vorteilhaft zur Minimierung der Leckströme sind, zu erhalten, werden die HfO2-Schichten, die oft kristallin sind, mit Aluminiumoxid (Al2O3) (k-Wert: 9) kombiniert, das bei wesentlich höheren Temperaturen amorph bleibt. Zwei Serien von ultra-dünnen Proben wurden durch Atomlagenabscheidung hergestellt: Mischschichten HfxAl1-xOz und Doppelschichten HfO2 auf Al2O3. Die optischen Konstanten und Bandlücken wurden mittels SE im Energiebereich von 0,7 bis 10 eV bestimmt. Es hat sich gezeigt, dass die (effektive) Bandlücke der Misch- und Doppelschichten durch die Komposition abgestimmt werden kann. Nach Lagerung der High-k-Schichten für zwei Monate an Luft konnte ein Alterungseffekt beobachtet werden. Dieser wird auf die weitere Oxidation der dielektrischen Schichten, die durch Sauerstoffdiffusion aus der Umgebungsluft in die High-k-Schichten ermöglicht wird, zurückgeführt.