Organic phosphorescence at room temperature is a strongly growing field of research. Together with fluorescence, it describes the radiative transitions of organic molecules after excitation with light of appropriate wavelength. While fluorescence is a process on the nanosecond timescale, organic phosphorescence is known to show afterglow emission in the lifetime range of microseconds to seconds. These long timescales result from quantum-mechanical restrictions in the transition processes underlying the phosphorescence. Namely, the involved electrons of the molecule have to undergo a spin flip, which is forbidden in zeroth-order approximation due to the necessity of conservation of angular momentum. In consequence, this emission feature of organic materials in general is obstructed at ambient temperature by dominating nonradiative deactivation channels. However, by careful design of the system, efficient phosphorescence at room temperature can be realized. In recent years, the number of publications introducing new organic phosphorescent emitters has continuously increased. However, to that date, the high quantity of described materials is not matched by an adequate amount of proposed applications. In fact, most publications present the synthesis of the substances as well as the morphology of the system, but only briefly address possible subsequent developing steps. In this thesis, as a first step, recent developments in that area are compiled to a broad overview, which includes proposed applications like sensing and optical data storage. Beyond that, a newly detected photophysical effect is introduced and evaluated, which enables the reversible activation of phosphorescence in a thin and transparent film. Since for many emitter materials the presence of adjacent molecular oxygen leads to a complete vanishing of phosphorescence, this emission can locally be tuned by manipulating the respective oxygen concentration. It is shown that a very elegant, non-contact way of achieving that is by using light of different wavelengths only. In detail, radiation in the near UV or blue regime can induce a chemical reaction of the oxygen and its environment, leading to an oxygen depletion at the illuminated regions. By covering the system with suitable barrier layers, no fresh oxygen can refill the system and phosphorescence becomes visible at the respective areas. By that, any luminescent image can be programmed into the transparent layers and be read out on demand. In addition, subsequent illumination with infrared radiation leads to a rise of the overall temperature, which consequently increases the permeability of the oxygen barrier. Therefore, the system is refilled with molecular oxygen and the pattern is erased. In a next step, new images can be written into the device. When not read out by illumination with appropriate light, the system is completely transparent and does not reveal the programmed information. That enables the fabrication of programmable luminescent tags, which allow multiple cycles of writing, reading and erasing, and thus may be used for temporary labeling in logistics or for invisible document security. Prototypes of the mentioned applications are manufactured and tested in this work, revealing the feasibility of their realization. The overall procedure as well as the device structure are part of patent applications. As a further part of the thesis, the characterization of multiple organic emitters and additives reveals that the effect of switchable phosphorescence is not limited to a particular material combination, but is rather a very general behavior. In consequence, device features like emission color, pattern contrast, or wavelength sensitivity are successfully optimized using suitable available organic systems. In order to facilitate a targeted development of new phosphorescent emitters in the future, the decisive demands on the materials to enable programmable tags are defined. Conclusively, more application pathways are depicted, of which one already successfully gained funding by the Federal Ministry of Education and Research of Germany. In this follow-up study, the suitability of the discovered results on sensing of UV radiation will be examined. With two more submitted proposals building up on the presented developments, the results of this thesis open up a broad range of further work both from the scientific and the engineering point of view.:1. Introduction 2. Theory 3. Methods 4. Basic Principles of Programmable Luminescent Tags (PLTs) 5. Characterization of Guest Materials 6. Optimization via Diversification: PLTs with Various Material Systems 7. Conclusions and Outlook / Organische Phosphoreszenz bei Raumtemperatur ist ein aktuell stark wachsendes Forschungsgebiet. Gemeinsam mit der Fluoreszenz beschreibt sie strahlende Übergänge von organischen Molekülen nach der Anregung mit Licht passender Wellenlänge. Während Fluoreszenz ein Prozess auf einer Zeitskala von Nanosekunden ist, zeigt organische Phosphoreszenz typischerweise ein längeres Nachleuchten im Bereich von Mikrosekunden bis Sekunden. Dieses resultiert daraus, dass die Übergangsprozesse, die zur Phosphoreszenz führen, quantenmechanisch nicht erlaubt sind. Die beteiligten Elektronen müssen sich einem Spin-Flip unterziehen, welcher in nullter Näherung aufgrund der Drehimpulserhaltung verboten ist. Infolgedessen wird die Phosphoreszenz organischer Materialien bei Umgebungstemperatur üblicherweise durch dominierende nichtstrahlende Relaxationswege unterdrückt. Durch gezielte Materialentwicklung lässt sich dennoch effiziente Phosphoreszenz realisieren. In den letzten Jahren ist die Zahl der Publikationen, in denen neue organische phosphoreszierende Emitter vorgestellt wurden, kontinuierlich gestiegen. Dieser hohen Auswahl an Materialien steht aktuell jedoch keine ausreichende Anzahl von Vorschlägen potentieller Anwendungen gegenüber. Tatsächlich stellen die meisten Publikationen die Synthese der Substanzen und die Morphologie des Systems vor, gehen aber nur kurz auf mögliche weitere Entwicklungsschritte ein. In dieser Arbeit werden nun zunächst die jüngsten Entwicklungen auf diesem Gebiet zu einem breiten Überblick zusammengestellt, der auch einige der vorgeschlagenen Anwendungen wie Sensorik und optische Datenspeicherung umfasst. Darüber hinaus wird ein neu entdeckter photophysikalischer Effekt vorgestellt und bewertet, der die reversible Aktivierung von Phosphoreszenz in einem dünnen und transparenten Film ermöglicht. Da bei vielen organischen Emittermaterialien die Nähe zu molekularem Sauerstoff zu einem vollständigen Verschwinden der Phosphoreszenz führt, kann diese Emission lokal durch Veränderung der Sauerstoffkonzentration beeinflusst werden. Eine sehr elegante, berührungslose Methode hierfür ist die zielgerichtete Bestrahlung mit Licht verschiedener Wellenlängen. So kann Strahlung im nahen UV- oder im blauen Bereich eine chemische Reaktion des Sauerstoffs mit seiner Umgebung auslösen, die zu einer Abnahme der Sauerstoffmenge in den beleuchteten Bereichen führt. Durch eine zusätzlich aufgebrachte Barriereschicht kann kein frischer Sauerstoff in das System nachströmen, weshalb an den entsprechenden beleuchteten Stellen nach ausreichender Bestrahlung Phosphoreszenz sichtbar wird. Dadurch kann ein beliebiges lumineszentes Muster in die transparenten Schichten einprogrammiert und bei Bedarf ausgelesen werden. Durch die Beleuchtung mit Infrarotstrahlung hingegen wird die Temperatur und damit auch die Durchlässigkeit der Sauerstoffbarriere erhöht. So wird das System mit molekularem Sauerstoff wieder aufgefüllt und die Phosphoreszenz verschwindet. Daraufhin können erneut Bilder in die Folie geschrieben werden. Wenn nicht durch Bestrahlung mit entsprechendem Licht ausgelesen, ist das System völlig transparent und lässt das eingeschriebene Muster nicht erkennen. Dies ermöglicht die Herstellung von programmierbaren lumineszenten Etiketten, die mehrere Schreib-, Lese- und Löschzyklen ermöglichen und somit zur temporären Beschriftung in der Logistik oder zur unsichtbaren Dokumentensicherung eingesetzt werden können. Die Machbarkeit der genannten Anwendungen wird in der Arbeit durch die Herstellung funktionierender Prototypen aufgezeigt. Sowohl das Gesamtverfahren von Aktivierung und Deaktivierung als auch der Aufbau des Systems sind Teil von Patentanmeldungen. Die im Rahmen dieser Arbeit erfolgte Charakterisierung weiterer organischer Emitter und Additive zeigt, dass der Effekt der schaltbaren Phosphoreszenz nicht auf eine bestimmte Materialkombination beschränkt ist, sondern ein sehr allgemeingültiges Verhalten darstellt. Deshalb werden Eigenschaften der Materialsysteme wie die Emissionsfarbe, der Kontrast der Muster oder die Empfindlichkeit gegenüber verschiedenen Lichtwellenlängen mit geeigneten Kombinationen optimiert. Um in Zukunft eine gezielte Entwicklung von organischen phosphoreszierenden Emittern zu ermöglichen, werden die entscheidenden Anforderungen an die Materialien bezüglich ihres Einsatzes in programmierbaren Etiketten dargestellt. Abschließend werden potentielle weitere Entwicklungsrichtungen hin zu weiteren Anwendungen beschrieben, von denen eine bereits Gegenstand von erfolgreich eingeworbener Förderung durch das Bundesministerium für Bildung und Forschung ist. In dieser Folgestudie wird die Eignung der gefundenen Ergebnisse zur Messung von UV-Strahlung untersucht. Mit zwei weiteren eingereichten Anträgen, die auf den vorgestellten Entwicklungen aufbauen, eröffnen die Ergebnisse dieser Arbeit sowohl aus wissenschaftlicher als auch aus technischer Sicht ein breites Spektrum weiterer Forschungsarbeiten.:1. Introduction 2. Theory 3. Methods 4. Basic Principles of Programmable Luminescent Tags (PLTs) 5. Characterization of Guest Materials 6. Optimization via Diversification: PLTs with Various Material Systems 7. Conclusions and Outlook

This thesis aims to abstract the physical layer (PHY) performance of current and upcoming technologies, so that, their suitability for various use cases and scenarios could be evaluated within an affordable time. For the said purpose, a new effective SINR mapping technique eEESM along with the dynamic optimization of the fitting parameter is proposed. The mapping accuracy of proposed eEESM techniques is analyzed and compared against the other state-of-the-art methods in the doubly selective channel. The results show that the proposed technique is more accurate and map closest to the reference packet error rate (PER) curves. Moreover, the mapping error of eEESM is the lowest for all considered MCSs. The justification for its better performance is the tighter symbol error rate (SER) approximation used to derive effective SINR and the proposed optimization approach. The main purpose of using PLA instead of full PHY simulations is to reduce simulation time. Therefore, a novel concept is presented to abstract PHY performance depending on the time and frequency selectivity of the channel. This further reduces the number of computations required to estimate performance using PLA. To demonstrate the gain in terms of simulation time, the computation complexity of PLA is compared against full PHY simulations. Results show that PLA is roughly 1000 to 1000000 times faster (depending on the abstracted fading conditions) compared to the PHY simulator. The effective SINR mapping approach is then further extended for future candidate multi-carrier techniques (i.e., OFDM, DFT-s-OFDM, GFDM, OTFS), which could be adopted by the upcoming technologies. For this purpose, the received SINR of symbols received through these multi-carrier techniques is derived. The resultant received SINR also considers the impact of ICI due to Doppler. Subsequently, the received SINR of symbols is mapped to effective SINR considering the selectivity of the channel. By comparing the effective SINR, OTFS outperforms other techniques. The reason for the better performance of OTFS is due to the spread of symbol energy over time and frequency, which results in higher effective SINR due to higher diversity. Furthermore, evaluation results show that the proposed PLA can accurately model the performance of these multi-carrier techniques under various fading conditions. Multi-connectivity is another enhancement being considered for future technologies, as an enabler for ultra-reliable communications under harsh channel conditions. Therefore, multi-connectivity communications are also studied in this thesis. Specifically, the frequency domain multi-connectivity networks are presented. To fully exploit frequency diversity under frequency selective channels, the subcarrier-based link combing scheme is proposed. The earlier derived received SINR is then extended for the state-of-the-art link combining schemes, i.e., SC, EGC, and MRC. The multi-connectivity gain in terms of the average received SINR is derived and compared for the above-mentioned combining schemes. To abstract the performance of multi-connectivity communications, the post-combined effective SINR mapping is proposed, where effective SINR represents the combined performance of connected links. The developed PLA performance is validated against the PHY simulations for the case of MRC. Results reveal that with the increase in multi-connectivity order, the RMSE error decreases due to the decrease in the variance of mapping SINRs. In the end, various applications of PLA are demonstrated. The developed multi-carrier PLAs are used to compare the performance of multi-carrier techniques under various fading conditions. Results depict that PER of multi-carrier techniques generally decreases with the increase in time or frequency selectivity, given that, the ideal channel estimation, ICI, and inter-symbol interference (ISI) cancellation is used. The multi-connectivity evaluation results depict that with the increase in channel selectivity higher diversity gain could be achieved. Besides, the proposed subcarrier-wise combining scheme achieves better performance compared to the traditional link combining approach. The next PLA application demonstrated is the performance comparison of V2X technologies, i.e., IEEE~802.11p, LTE-V2V, IEEE~802.11bd, and NR-V2X, in an Urban NLOS communications scenario. It is observed that 802.11bd outperforms other technologies in terms of PER and packet reception ratio (PRR). Its better performance is due to lower ICI compared to LTE-V2X and NR-V2X, and due to the use of LDPC codes compared to 802.11p. In contrast, NR-V2X outperforms other technologies in terms of data rates and packet inter-arrival time. The last PLA application shown is the link adaptation for single-link and multi-connectivity communications. In single-link communication, the performance of various PLA techniques is compared in terms of achieved data rates and outage probability against the case of perfect CQI. The CQI based on the proposed eEESM technique improves the data rates and reliability of the link, compared to other schemes. Further, in the case of multi-connectivity, the post-combined effective SINR mapping proposed in this thesis is used for link adaptation in terms of both MCS selection and adapting the number of links. The proposed scheme optimizes multi-connectivity data rates while using the lowest possible number of links required for the desired quality of service.

Reconfigurable field effect transistors (RFET) have the ability to toggle polarity between n- and p- conductance at runtime [1], [2]. The here presented multiple independent gate (MIG) RFET expands the device functionality by offering additional logical inputs, valuable for e.g. efficient XOR or majority gate implementations [3], [4] or the here originally presented multiplexer circuit. Moreover,https://inspec.iet.org/ideas/#controlled-terms for the first time with a top-down RFET approach equal ON-currents are obtained for every configuration while requiring only one supply voltage (VDD).

Silicon Nanowire (SiNW) based reconfigurable fieldeffect transistors (RFETs) provide an additional gate terminal called the program gate which gives the freedom of programming p-type or n-type functionality for the same device at runtime. This enables the circuit designers to pack more functionality per computational unit. This saves processing costs as only one device type is required, and no doping and associated lithography steps are needed for this technology. In this paper, we present a complete design flow including both logic and physical synthesis for circuits based on SiNW RFETs. We propose layouts of logic gates, Liberty and LEF (Library Exchange Format) files to enable further research in the domain of these novel, functionally enhanced transistors. We show that in the first of its kind comparison, for these fully symmetrical reconfigurable transistors, the area after placement and routing for SiNW based circuits is 17% more than that of CMOS for MCNC benchmarks. Further, we discuss areas of improvement for obtaining better area results from the SiNW based RFETs from a fabrication and technology point of view. The future use of self-aligned techniques to structure two independent gates within a smaller pitch holds the promise of substantial area reduction.

In this paper, we consider devices, circuits, and systems comprised of transistors with integrated ferroelectrics. Said structures are actively being considered by various semiconductor manufacturers as they can address a large and unique design space. Transistors with integrated ferroelectrics could (i) enable a better switch (i.e., offer steeper subthreshold swings), (ii) are CMOS compatible, (iii) have multiple operating modes (i.e., I-V characteristics can also enable compact, 1-transistor, non-volatile storage elements, as well as analog synaptic behavior), and (iv) have been experimentally demonstrated (i.e., with respect to all of the aforementioned operating modes). These device-level characteristics offer unique opportunities at the circuit, architectural, and system-level, and are considered here from device, circuit/architecture, and foundry-level perspectives.

Logic-in-memory circuits promise to overcome the von-Neumann bottleneck, which constitutes one of the limiting factors to data throughput and power consumption of electronic devices. In the following we present four-input logic gates based on only two ferroelectric FETs (FeFETs) with hafnium oxide as the ferroelectric material. By utilizing two complementary inputs, a XOR and a XNOR gate are created. The use of only two FeFETs results in a compact and nonvolatile design. This realization, moreover, directly couples the memory and logic function of the FeFET. The feasibility of the proposed structures is revealed by electrical measurements of HKMG FeFET memory arrays manufactured in 28nm technology.

During the last decade ferroelectrics based on doped hafnium oxide emerged as promising candidates for realization of ultra-low-power non-volatile memories. Two spontaneous polarization states occurring in the material that can be altered by applying electrical fields rather than forcing a current through and the materials compatibility to CMOS processing are the main benefits setting the concept apart from other emerging memories. 1T1C ferroelectric random access memories (FeRAM) as well as 1T FeFET concepts are under investigation. In this article the application of hafnium based ferroelectric memories in different flavours and their ranking in the memory landscape are discussed.

The use of ferroelectric negative capacitance (NC) has been proposed as a promising way to reduce the power dissipation in nanoscale devices [1]. According to single-domain (SD) Landau theory, a hysteresis-free NC state in a ferroelectric might be stabilized in the presence of depolarization fields below a certain critical film thickness tF, SD. However, it is well-known that depolarization fields will cause the formation of domains in ferroelectrics to reduce the depolarization energy [2], which is rarely considered in the literature on NC [3]. The improvident use of SD Landau theory to model NC devices seems to be the main reason for the large discrepancy between experimental data and the current theory [4]. Here, we will show by simulation how anti-parallel domain formation can strongly limit the stability of the NC state in a metal-ferroelectric-insulator-metal (MFIM) structure, which is schematically shown in Fig. 1.

The influence of depolarization and its role in causing data retention failure in ferroelectric memories is investigated. Ferroelectric Hf₀.₅Zr₀.₅O₂ thin films 8 nm thick incorporated into a metal-ferroelectric-metal capacitor are fabricated and characterized with varying thicknesses of an Al₂O₃ interfacial layer. The magnitude of the depolarization field is adjusted by controlling the thickness of the Al₂O₃ layer. The initial polarization and the change in polarization with electric field cycling is strongly impacted by the insertion of Al₂O₃ within the device stack. Transient polarization loss is shown to get worse with larger depolarization fields and data retention is evaluated up to 85 °C.

Silicon Nanowire based Reconfigurable Field Effect Transistor (SiNW RFET) presents a solution to increase the system functionality beyond the limits of classical CMOS scaling in More-than-Moore era of semiconductor technology. They are not only spatially reconfigurable, i.e., the source and the drain can be interchangeable in design, but in such devices one can also control the primary charge carrier by controlling the voltage in the control gate. The two key morphological factors controlling reconfigurability are the structure and composition of the Schottky junctions, which serve as the location for Program and Control gates and radial strain induced by the self-limiting oxidation, which influences the carrier mobility resulting in symmetric p and n characteristic curves of an RFET. Despite its potential, in-depth nanoscale studies on the structural and compositional characterization of the key features controlling the reconfigurability are limited and thereby presents as a novel area of research. In this study, the composition and morphology of the Schottky junction and the radial strain profile due to self-limiting oxidation were studied using advanced imaging and sample preparation techniques like Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) imaging alongside with precise sample preparation methods like Focused Ion Beam (FIB) liftout techniques. For analysis of radial strain in nanowires that underwent self-limiting oxidation, a TEM lamella was taken of a cross-section of the NW. The lamella was kept at 200 nm thickness to preserve the strain state of the nanowire cross-section. It was observed that nanowires undergoing such oxidation have an omega (Ω) shaped oxide shell where the shell was discontinued at the spot where the nanowire was touching the substrate. Fast Fourier transform of the high-resolution image of such a NW crossection was used to calculate the strain profile. The strain is also found to be not radially uniform for such Ω shaped oxide shells. The strain profile shows a local maxima near the nanowire base where it touches the substrate then a minima approximately at the geometric center followed by the maximum strain at the area adjacent to the oxide shell thereby showing a sinusoidal profile. Theoretical simulations performed by Dr. Tim Baldauf further verified the nature of the sinusoidal strain that was observed experimentally. Similar simulations were done for different omega shell shapes, which yielded strain plots of similar sinusoidal strain plots, with the local maxima depending on the level of encapsulation of the NW by the shell. In the characterization of the Schottky junction, a TEM lamella was taken along the longitudinal direction of a nanowire, which was silicidized from both ends, similar to ones used in SiNW RFET devices. High resolution TEM micrographs and EDX (Energy dispersive X-Ray Spectroscopy) in the TEM along the Schottky junction showed a Ni rich phase and pure Si on either side of the junction. This participating phase was identified as NiSi2. However, the transition between the phases shows a gradient and in-situ experiments were designed to verify the sharpness of the junction. In in-situ silicidation experiments, Si nanowires with a thin native oxide shell were distributed on an electron transparent surface and were partially covered with Ni islands by shadow sputtering. The whole setup was then heated in a heating stage of a TEM and the Ni was allowed to disperse within the Si nanowires forming NiSi2. HRTEM (High Resolution TEM), EDX and EELS (Electron Energy Loss Spectroscopy) studies were performed on the silicidized samples for further ex-situ analysis. During the in-situ experiment, it was observed that Ni-phase interface is atomistically sharp and seldom progresses perpendicularly to the nanowire’s direction but through the closed packed planes of the NW. The interface velocity at different temperatures was used to calculate the activation energy of the silicidation process. The value of the activation energy indicates the Ni undergoing volume diffusion through the Ni-rich phase. The velocity of the interface was observed to be much higher in nanowires with smaller diameters than those with higher diameters, further proving the hypothesis. During the in-situ experiments, in around 10% of nanowires that underwent complete silicidation and held isothermally, the crystalline silicide phase was observed to partially or fully diffuse out of the nanowire core, leaving only a thin shell of Silicon oxide forming ultra-thin walled SiO2 nanotubes (NT). The onset and the time required for completion of the process varies in the nanowires depending on size of the nanowire, the distance and contact to the nearest Ni islands and presence of defects such as kinks and twists within the nanowire. In order to study the dynamics of the process, the velocity of the receding front was calculated for nanowires of two different diameters. They are found to be identical, indicating the volume flow rate of the process is directly proportional to the cross-sectional area. The voids were formed by the reduced diffusivity of Ni in Ni2Si phase in comparison to phases with lower percent of Ni. This indicates that the reason behind the phenomenon is coalition of Kirkendall voids and thus dependent on volume diffusion. From this study, it can be concluded that the extent of self-limiting oxidation and shape of the shell can influence the radial strain state. This can be used to manipulate the strain to tailor the electron and hole transfer characteristics within the RFET. A variety of factors including temperature, time, orientation and radius of the nanowires has been studied with respect to silicidation of a SiNW. The calculated activation energy can be used for precise process control over the location and morphology of Schottky junction. Although not directly related to SiNW RFET devices, the self-assembly of ultra-thin-walled SiO2 NT is a novel research area in itself, the findings of which can be applied in to design novel electronics and sensors.:TABLE OF CONTENTS Preface List of Abbreviations CHAPTER 1: Introduction and Motivation 1.1 Definition and History 1.2 Synthesis Routes 1.3 Properties and Applications 1.4 Nanoscale Electronics and Role of Si Nws 1.4.1 1.4.2 SiNW Reconfigurable Field Effect Transistor 1.5 Introduction to The Topic of The Thesis 1.6 Outline of The Thesis CHAPTER 2: Physical Basics and Previous Research: A Short Summary 2.1 Strain Measurement and Effects of Strain on on Nanoelectronics 2.1.1 Strain Analysis in Planar CMOS Structures 2.2 Silicidation and Schottky Junction 2.2.1 In-situ Silicidation 2.2.2 Silicon oxide nanotubes CHAPTER 3: Background of Instruments and Experimental Set-up 3.1 Scanning Electron Microscope 3.2 Transmission Electron Microscope 3.2.1 Imaging Techniques 3.2.2 TEM sample preparation 3.3 Focused Ion Beam CHAPTER 4: Strain in Nanowire 4.1 Goal of This Study 4.2 Strain in SiNW RFET Devices 4.3 Strain Analysis in SiNW Cross-section 4.3.1 Sample Preparation 4.3.2 Experimental Process 4.3.3 Results and Discussion 4.4 Conclusions CHAPTER 5: Schottky Junction 5.1 Crystallographic Data on Nickel Silicides 5.2 Formation of Silicides in 2-D Structures 5.2.1 Sample History 5.2.2 Sample Preparation 5.2.3 Results and Discussion 5.3 Formation of Silicides in 1-D Structures: Schottky Junction in NWs 5.3.1 Sample History 5.3.2 Sample Preparation 5.3.3 Results and Discussion 5.3.4 Shortcomings of The Lift-out Technique 5.4 In-situ Silicidation 5.4.1 Motivation 5.4.2 Sample Preparation 5.4.3 Experimental Procedure 5.4.4 Results and Discussions 5.4.5 Shortcoming of The Experiment 5.5 Self-assembling SiO2 Nanotubes 5.5.1 Sample Preparation 5.5.2 Experimental Process 5.5.3 Results and Discussion . 5.5.4 Post In-situ Experiment TEM Analysis 5.5.5 Conclusions CHAPTER 6: Conclusions and Outlook 6.1 Strain Analysis 6.2 Schottky Junction Studies Bibliography Acknowledgements