Les puits quantiques InGaN/GaN montrent la plus grande efficacité connue dans le bleu-UV et le défi actuel dans ce type de matériau est de pousser leur émission vers les grandes longueurs d’ondes. Ceci serait possible en augmentant la composition en indium, mais il faut alors gérer les contraintes résultantes. Ce travail a mis en œuvre la microscopie électronique en transmission et la diffraction des rayons X pour déterminer la composition chimique à l’intérieur des couches InGaN, le taux de relaxation et le type de défauts présents. Les résultats montrent qu’il n’y a pas de fluctuations de composition en indium dans les couches d’InGaN étudiées avec des taux d’indium de l’ordre de 20%. Ainsi, la différence d’émission des échantillons pourrait s’expliquer par la variation d’épaisseur des puits quantiques InGaN et laprésence de défauts. En effet, plusieurs types de défauts ont été observés et caractérisés tels que les pinholes ou des domaines de défauts plans selon leur origine. Dans les multicouches InGaN/GaN avec couches AlGaN compensatrices de contrainte,la diffraction des rayons X a montré que lorsque l’épaisseur des couches d’AlGaN augmente en gardant constante l’épaisseur entre les couches actives d’InGaN (avec une valeur d’environ 16-17 nm), les puits quantiques sont totalement contraints dans le plan de croissance et en dehors. Par microscopie électronique, nous montrons queleur relaxation se fait par formation aussi bien de défauts en domaines plans que de dislocation de type a. Ces dislocations se propagent des pits quantiques vers la surface, et la densité des défauts augmente avec l’épaisseur des couches d’AlGaN. / InGaN/GaN quantum wells show the highest known emission efficiency in UV-blue and the current challenge is to push to longer wavelengths. This would be possible by increasing the indium composition but the challenge becomes how to handle the resulting strains. This work has combined transmission electron microscopy and Xray diffraction in order to determine the relaxation rates, the local chemical composition and defects formation in these systems. The results show that there are no composition fluctuations in these InGaN layers where the indium content was around 20%. Therefore, the differences in emission may be explained by the changes in quantum wells thicknesses and/or the presence of defects. Indeed, several types of defects have been observed and characterized, such as pinholes or planar defect domains. For InGaN/GaN quantum wells with strain compensating AlGaN layers, Xray diffraction showed that, when the AlGaN layer thickness increases, keeping constant the spacing between InGaN layers (around 16-17 nm), the quantum wellsare totally strained in and out the growth plan. Using transmission electron microscopy, it is shown that the relaxation occurs through the formation of domains as well as a type dislocations. The dislocations propagate from the quantum well tothe surface and the density of the defects increases with the thickness of the AlGaN layers.

This thesis examines the integration of adolescents of Vietnamese origin in the Ústí nad Labem region. For my research I chose a region with high unemployment, in which there are large Vietnamese and Roma minorities. The aim of the research is to establish how the Vietnamese young people are integrated alongside the Roma youth in the region, to get to know these two different minorities, to assess, on the basis of a comparison, the degree of integration of the Vietnamese youth, and to determine what impact the aggravating factors in the place where they live has on these adolescents. The general part of the thesis deals with the arrival of the Vietnamese minority in the Czech Republic in the past and the present, and with the coexistence of this minority with the original inhabitants in our country and the neighbouring countries of Central Europe. It presents the organisations that help this specific group and other supportive networks that newcomers to the Czech Republic can make use of. A further section is devoted to the Roma minority in the Ústí nad Labem region. It thus compares two different types of integration of minorities. The practical part examines the opinions of the adolescents themselves. I investigated how these young people view the fact that they are different, what they know...

Straková, P. Quality and customer satisfaction in the hotel industry. Diploma thesis. Brno: Mendel University, 2017. Diploma thesis is about the quality of services in the hotel industry from customers' views and a partial view of the service provider. Work includes analysis of current customer satisfaction with the services provided in Texas and the Czech Republic. Recommendations are made on the basis of customer satisfaction surveys for service providers. The theoretical part of this thesis contains findings from the scientific world literature focusing on quality and hotel industry. The practical part is based on analysis of current situation, questionnaire surveys, and evaluation of the results from the questionnaire survey, statistical investigation and final discussion.

This thesis is focused on how much are the adolescent people who belong to Vietnamese minority integrated in region Ústí. I have chosen this region because I wanted to define one place to be more exact, and also because this region is interesting for its high number of unemployed people and the people belonging to the Roma minority. That was the reason which made my task more interesting because I wanted to see how these factors affected the integration of another minority. In the practical part the thesis focuses on the approach of the Vietnamese people living in the Czech Republic in the past and nowadays. It also maps the coexistence of these specific minorities in the states of Central Europe with people living in these states. The thesis also acquaints the information about the organization and network which can be used for help and which are focused on the Vietnamese people. Practical part presents the opinions of adolescent people. I was asking them how they feel like a minority in interview. I chose ten respondents. This number was relevant for this task. Practical part is also based on observation on the high school where these respondents study. The main question is to where the youth born in one country with the different origin belong. How important it is what other people think of them.

This dissertation seeks to answer the question of whether and to what extent principles of natural law have figured in Supreme Court jurisprudence in the last two centuries. In the last quarter-century, scholars and judicial analysts have displayed a renewed interest in natural law reasoning and whether justices do or should take cognizance of natural law considerations. The issue became prominent during the 1991 confirmation hearings of Clarence Thomas, who had written and spoken favorably of natural law as a guiding principle in constitutional adjudication. Two cases and their progeny figure herein. In Calder v. Bull (1798), Supreme Court Justices Samuel Chase and James Iredell discussed whether principles of natural justice placed limits on legislatures beyond which they could not go, or whether judges could rely only on specific constitutional restraints in evaluating legislative acts. In Corfield v. Coryell (1823), Justice Bushrod Washington explained that the Constitution’s Privileges and Immunities Clause protects those rights that are “fundamental,” and many subsequent commentators and courts have given this statement a natural rights gloss. This work contributes to existing Supreme Court literature by tracing the entire history of Calder and Corfield, the two cases most frequently cited for potentially having natural law implications. The paper considers each citation as it is relevant to the natural law debate; cases are excluded only because they are cited for another point. For example, cases that cite Calder for its holding that the Constitution’s Ex Post Facto clause only applies to criminal cases are not considered. The paper concludes that natural law considerations now figure in Supreme Court jurisprudence only in a mediated sense. While several Eighteenth and Nineteenth Century opinions, including Corfield itself, accept natural law principles as interpretative guides, natural law as a free-standing source of adjudication has faded from Supreme Court jurisprudence. Concomitantly, the Privileges and Immunities Clause as a source of rights has been largely discarded in favor of a substantive due-process jurisprudence, with the Court adopting a gradual, common-law type of approach in determining the constitutional limits of government interference with Americans’ rights.

Bien que les nanofils III-V soient reconnus comme des candidats prometteurs pour le développement de cellules solaires de nouvelle génération pour leurs propriétés optiques très attractives, l'amélioration des performances attendue par rapport à leurs homologues 2D n'a pas encore été démontrée. L’investigation à l’échelle nanométrique est essentielle pour comprendre l'origine de l'écart existant entre les prédictions théoriques et les démonstrations expérimentales. L’analyse des nanofils uniques devrait permettre d'élucider les facteurs limitants (liés par exemple aux propriétés électriques des jonctions p-n internes, à l'homogénéité fil-à-fil et aux éventuelles défaillances) et de proposer des solutions pour améliorer les performances des dispositifs photovoltaïques à nanofils.Cette thèse explore l’utilisation des techniques de caractérisation par faisceau d’électrons pour extraire les paramètres fondamentaux pour la conversion photovoltaïque afin d’optimiser les propriétés de nanofils III-V crus sur Si.L’étude à l’échelle nanométrique porte tout d’abord sur des nanofils de GaAs et AlGaAs avec une jonction radiale. A la suite de cette étude, la structure interne de nanofils a pu être améliorée. La caractérisation de dispositifs de taille millimétrique confirme l’amélioration des performances à l’échelle macroscopique.Des nanofils InGaP crus par une nouvelle méthode (Template Assisted Selective Epitaxy où TASE) ont aussi été étudiés et le niveau de dopage a été estimé par la microscopie EBIC. De plus, la réponse photovoltaïque de ces structures été observée pour la premier fois. Les propriétés électriques des nanofils GaAs avec une jonction axiale crus par la même technique ont aussi été caractérisées.Enfin, des nanofils avec deux jonctions InP/InGaP sont été étudiés comme première tentative pour fabriquer une cellule solaire tandem entièrement à nanofils. L’activité électrique des deux jonctions été observée et caractérisée. En revanche, le fonctionnement de la structure tandem s’est trouvé limité par la jonction tunnel qui connecte électriquement les deux jonctions. / Although III-V nanowires (NWs) are recognized as promising candidates for the development of new generation solar cells thanks to their very attractive optical properties, the expected performance improvement over their 2D counterparts has not yet been demonstrated. Nanoscale analyses by electron beam-based techniques (EBIC,CL) are expected to elucidate the limiting factors and to propose solutions for enhancing the performance of NW photovoltaic (PV) devices.This PhD thesis applies the electron beam probe techniques to get access to the key parameters governing the PV conversion at a single NW level in order to further optimize the properties of III-V NWs grown on Si.First, GaAs and AlGaAs NWs containing a radial junction are investigated at the nanoscale and their internal structure is optimized. The characterization of mm-sized devices confirms the improvement of the device performance at the macroscopic level.Then InGaP and GaAs NWs grown by a novel Template Assisted Selective Epitaxy (TASE) method containing an axial junction are studied. The doping level in the ternary alloy is estimated by EBIC and the photovoltaic response of these structures is demonstrated for the first time.Finally, InP/InGaP dual junction NWs are characterized. Although both top and bottom junctions are electrically active under excitation, the performance of the tandem structure is limited by the connecting tunnel junction

La limite théorique d’efficacité d’une cellule solaire simple jonction est de ~29 %. Afin de dépasser cette limite, une des moyens les plus prometteurs est de combiner le silicium avec des matériaux III-V. Alors que la plupart des solutions proposées dans la littérature proposent de faire croître directement le matériau III-V sur substrat silicium, ce travail présente une approche innovante de fabriquer ces cellules solaires tandem. Nous proposons une approche inverse métamorphique, où le silicium cristallin ou SiGe est cru directement sur le matériau III-V par PECVD. La faible température de dépôt (< 200 °C) diminue les problèmes de différence de dilatation thermique, et le fait de croître le matériau IV sur le matériau III-V élimine les problèmes de polarité.La réalisation de la cellule tandem finale en SiGe/AlGaAs passe par le développement et l’optimisation de plusieurs briques technologiques. Tout d’abord, nous développons l’épitaxie à 175 °C de Si(Ge) sur des substrats de Si (100) dans un réacteur de RF-PECVD industriel. La réalisation de cellules solaires à hétérojonction à partir de ce matériau Si(Ge) crû par PECVD montre que ses performances électriques s’avèrent prometteuses. Nous obtenons pour un absorbeur de 1.5 µm des Voc qui atteignent 0.57 V. L’incorporation de Ge permet d’augmenter le JSC de 15.4 % jusqu’à 16.6 A/cm2 pour Si0.72Ge0.28.En parallèle, la croissance de cellules solaires AlGaAs a été développée, ainsi que sa fabrication technologique. Nous obtenons une efficacité de 17.6 % pour une cellule simple en Al0.22Ga0.78As. Nous développons aussi des jonctions tunnel, parties essentielles d’une cellule tandem dans une configuration à deux terminaux. Nous développons notamment le dopage n du GaAs en utilisant le précurseur DIPTe, et obtenons des jonctions tunnel ayant des courants pic atteignant jusqu’à 3000 A/cm2, rejoignant ainsi les résultats de l’état de l’art.Ensuite, nous étudions l’hétéro-épitaxie de Si sur GaAs par PECVD. Le c-Si montre d’excellentes propriétés structurales. Les premiers stades de croissance sont étudiés par diffraction des rayons X avec rayonnement synchrotron. Nous trouvons un comportement inattendu : le Si est relâché dès les premiers nanomètres, mais sa maille est tétragonale. Alors que le GaAs a un paramètre de maille plus grand que le Si, le paramètre hors du plan (a⏊) du Si est plus élevé que son paramètre dans le plan (a//). Nous trouvons une forte corrélation entre cette tétragonalité et la présence d’hydrogène dans la couche de silicium. D’autre part, nous montrons que le plasma d’hydrogène présent lors du dépôt PECVD affecte les propriétés du GaAs : son dopage diminue d’environ un ordre de grandeur lorsque le GaAs est exposé au plasma H2, dû à la formation de complexes entre le H et le dopant (C, Te ou Si). Le dopage initial peut être retrouvé après un recuit à 350 °C.Enfin, nous étudions la dernière étape de fabrication de la cellule tandem : le collage. Nous avons pu reporter une cellule simple inversée en AlGaAs sur un substrat hôte (en Si), retirer le substrat GaAs et effectuer les étapes de microfabrication sur un substrat 2 pouces. Des couches épaisses de Si (>1 µm) ont été crues avec succès sur une cellule AlGaAs inversée suivie d’une jonction tunnel. Le collage de cette cellule tandem, et la processus de fabrication technologique du dispositif final sont ensuite étudiés, afin de pouvoir caractériser électriquement la première cellule solaire tandem fabriquée par croissance inverse métamorphique de Si sur III-V. / Combining Silicon with III-V materials represents a promising pathway to overcome the ≈29% efficiency limit of a single c-Si solar cell. While the standard approach is to grow III-V materials on Si, this work deals with an innovative way of fabricating tandem solar cells. We use an inverted metamorphic approach in which crystalline silicon or SiGe is directly grown on III-V materials by PECVD. The low temperature of this process (<200 °C) reduces the usual thermal expansion problems, and growing the group IV material on the III-V prevents polarity issues.The realization of the final tandem solar cell made of SiGe/AlGaAs requires the development and optimization of various building blocks. First, we develop the epitaxy at 175°C of Si(Ge) on (100) Si substrates in an industrial standard RF-PECVD reactor. We prove the promising electrical performances of such grown Si(Ge) by realizing PIN heterojunction solar cells with 1.5µm epitaxial absorber leading to a Voc up to 0.57 V. We show that the incorporation of Ge in the layer increases the Jsc from 15.4 up to 16.6 A/cm2 (SiGe28%).Meanwhile, we develop the growth of AlGaAs solar cells by MOVPE and its process flow. We reach an efficiency of 17.6 % for a single Al0.22GaAs solar cell. We then develop the tunnel junction (TJ), essential part of a tandem solar cell with 2-terminal integration. We develop the growth of n-doped GaAs with DIPTe precursor to fabricate TJs with peak tunneling currents up to 3000 A/cm2, reaching state-of-the art TJs.Then, the hetero-epitaxy of Si on GaAs by PECVD is studied. c-Si exhibits excellent structural properties, and the first stages of the growth are investigated by X-ray diffraction with synchrotron beam. We find an unexpected behavior: the grown Si is fully relaxed, but tetragonal. While the GaAs lattice parameter is higher than silicon one, we find a higher out-of-plane Si parameter (a⏊) than in-plane (a//), contradicting the common rules of hetero-epitaxy. We find a strong correlation between this tetragonal behavior and the presence of hydrogen in the Si layer. We furthermore show that hydrogen also plays a strong role in GaAs: the doping level of GaAs is decreased by one order of magnitude when exposed to a H2 plasma, due to the formation of complexes between H and the dopants (C, Te, Si). This behavior can be recovered after annealing at 350°C.Finally, the last step of device fabrication is studied: the bonding. We successfully bonded an inverted AlGaAs cell, removed it from its substrate, and processed a full 2” wafer. We succeeded in growing our first tandem solar cells by growing thick layers (>1 µm) of Si on an inverted AlGaAs solar cells followed by a TJ. The bonding and process of this final device is then performed, leading, as a next step, to the electrical measurement of the very first tandem solar cell grown by inverted metamorphic growth of Si on III-V.

Yes / Voltage instability problems in power system are an important issue that should be taken into consideration during the planning and operation stages of modern power system networks. The system operators always need to know how far the power systems from voltage collapse in order to apply suitable action to avoid unexpected results. This paper propose a review of some static voltage stability indices found in the literature to study voltage collapse reveals that various analytical tools based on different concept to predict voltage collapse phenomena. These static voltage stability indices present reliable information about the closeness of the power system to voltage collapse and identification of the weakest bus, line and area in the power network. A number of static voltage stability indices have been proposed in the literature, but in this only four of them will be considered. The effectiveness of these indices is demonstrated through studies in IEEE 14 bus reliability test system. The results are discussed and key conclusion presented. / MSCRC

Zugl.: Köln, Universiẗat, Diss., 2003.

The goal of this thesis is to describe the effective legislation of the cooperatives. Where appropriate this thesis compares the effective legislation to the previous legislation. The thesis tries to locate the problematic areas and to find solution to the given problems. This thesis is divided into 5 main chapters. The first chapter describes the history of cooperatives, because I think that without understanding the historic development no topic can be properly understood. Also this chapter describes the cooperative at a general level. The second chapter is formed of a general description of the membership in a cooperative with comparison to the previous legislation. This chapter covers also the basic principles of the membership in cooperative, as well as the content of the membership in cooperative. The third chapter describes the individual methods of the formation of the membership in cooperative pursuant to the effective legislation and where appropriate compares it to the previous legislation. It describes formation of the membership in the moment of formation of the cooperative and the procedure that needs to be followed. Also it describes the joint membership of the spouses in the housing cooperative. The fourth chapter deals with the alteration of the membership in the cooperative, which...