Ce travail de thèse, effectué en collaboration avec la société PHOTONIS, un des leaders mondiaux dans la conception de tubes intensificateur de lumière, et l'Institut d'Électronique du Sud de l'Université de Montpellier, a pour but l'optimisation des photocathodes de 3e génération à base d'(In)GaAs pour lunettes de vision nocturne. Après avoir décrit le principe d'un tube intensificateur de lumière et présenté les performances atteintes par ces différentes générations de dispositifs, le cas plus spécifique de la photocathode est abordé. Par la simulation des performances, deux structures photocathodes sont proposées. L'une pour la détection des faibles niveaux de lumière résiduelle dans le visible, l'autre pour l'extension de la réponse spectrale vers le domaine du proche infrarouge (λ=1,06µm). Le processus technologique pour la fabrication de photocathodes de hautes performances est décrit étape par étape puis les caractérisations électro-optiques, associées aux composants réalisés, sont présentées. Les résultats obtenus montrent des performances en termes de réponse spectrale qui dépassent régulièrement les 1600µA/lm. / This thesis reports on the optimization of 3rd generation photocathode based on (In)GaAs materialfor night vision google. It is realized in collaboration between the PHOTONIS Company, one of the world leaders in conception of image intensifier and the Institut d'Électronique du Sud from Montpellier University. After a description of an image intensifier operation and a presentation of the state of the art of the image intensifier devices, the more specific case of the photocathode is described. Two photocathodes structures are deduced from simulation of performances, one for detection of low levels of visible residual light and the other for infrared extension of spectral response (λ=1.06µm). The different steps of the technological process for the manufacturing of high efficiencies photocathodes are described and the electro-optical characterizations made are presented. The results show performances as hight as 1600$µA/lm.

The beginning of the space-age in the 1950s led to interest in the effects of radiation on semiconductors. The systematic investigation of defect centres in semiconductors began in earnest over 30 years ago. In addition to defect identification, information was also obtained on energy-level structures and defect migration properties. When designing electronic systems for operation in a radiation environment, ~tis imperative to know the effect of radiation on the properties of electronic components and materials comprising these systems. In some instances, the effects of irradiating electronic materials can be used to obtain desired material properties (mesa isolation, implantation, etc.). However, when electronic devices are exposed to radiation, defects may be introduced into the material. Depending on the application, these defects may have a detrimental effect on the performance of such a device. For this study, the semiconductor gallium arsenide (GaAs) was used and the defects were introduced by electrons, alpha-particles, protons, neutrons and argon sputtering. These particles were generated using radio-nuclides, a high-energy neutron source, a 2.5 MV Van de Graaff accelerator and a sputter gun. The influence of particle irradiation on the device properties of Schottky barrier diodes (SBDs) fabricated on GaAs is presented. These device properties were monitored using a variable temperature current-voltage (I-V) and capacitance-voltage (C-V) apparatus. In order to have an understanding of the change in electrical properties of these contacts after irradiation, it is necessary to characterize the radiation-induced defects. Deep level transient spectroscopy (DLTS) was used to characterise the defects in terms of their DLTS "signature", defect concentration, field enhanced emission, and thermodynamic properties. / Thesis (PhD)--University of Pretoria, 1994. / gm2014 / Physics / unrestricted

Inhalt der Arbeit waren die Überprüfung der Leistungsfähigkeit der beiden Verfahren Mikrowellendetektierte Photoleitung (MD-PL) und Mikrowellendetektierte Photo Induced Current Transient Spectroscopy (MD-PICTS) sowie ihre praktische Anwendung auf den Halbleiter GaAs. Zerstörungsfreie Photoleitungs-Wafertopogramme geben Auskunft über die Verteilung des Defekts EL20 bzw. über Widerstand und Ladungsträgerlebensdauer im Volumen eines Wafers bzw. seiner Oberfläche. MD-PICTS-Topographie weiterer Defekte ist möglich. Die Verfahren brachten ein neues Verständnis der bei PICTS ablaufenden Prozesse - die Peakhöhe ist nicht für alle Defekte unmittelbar proportional zur Defektkonzentration. Für die Erklärung positiver und negativer EL2- und EL3-PICTS- Peaks wurde ein Modell entwickelt, nach dem es sich bei diesen Defekten um Rekombinationszentren handelt. Das Modell wurde durch Simulationsrechnungen bestätigt. Ferner entstanden Ergebnisse zum Defekt EL6, an getemperten Wafern und an Epitaxieschichten.

Cloud gaming, also known as Gaming as a Service or GaaS is a quickly developing service with significant economic potential. Author follows this trend and focuses on the topic of providing videogames as a service through cloud environment. The goal of this work was to analyse and describe legal relations between authors of videogames, providers, and users of GaaS in the context of Czech copyright and to present practical consequences of these relations, mainly in contrast to SaaS. Firstly, the reader is acquainted with basic aspects of videogames with emphasis on classification and description of videogames and its parts, i.e. computer program and other elements, as a work of authorship. Author describes possible theoretical views on the protection of audio-visual components of videogames. It is then pointed out that no satisfactory classification of video game as a singular work of authorship can be provided under the Czech Copyright Act. Videogame legislation is also proposed. Subject of the second section of this thesis is cloud gaming technology. This segment is written as to be understandable even for non-experts in the field. At first basic types of cloud services are presented. Then, the technology behind cloud gaming is described, along with business models one can come across nowadays....

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