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O gênero Streptomyces constitui-se em um grupo diferenciado de procariotos fitopatogênicos, por serem morfologicamente similares aos fungos e produzirem diversos importantes metabólitos secundários. A sarna comum da batata é principal doença causada pelo gênero. O principal agente causal da doença, Streptomyces scabies, produz fitotoxinas denominadas concanamicinas, porém, não foi comprovada a importância da produção das mesmas na agressividade dos isolados de S. scabies. Dessa forma, neste trabalho procurouse avaliar a reação dos cultivares mais plantados no Brasil a isolados de S. scabies exibindo diferentes níveis de produção de concanamicinas. O nível de produção de concanamicinas A e B de dez isolados de Streptomyces spp. foi avaliado por cromatografia líquida de alta pressão (HPLC) e dois isolados (produtor de alto nível da toxina; baixo produtor) foram selecionados e utilizados na avaliação da resistência de seis cultivares de batata em casa de vegetação. Vasos contendo o substrato esterilizado receberam a suspensão de esporos bacterianos junto com os tubérculos sadios no momento do plantio e após quatro meses, a severidade da doença foi avaliada. Os resultados demonstraram aumento na agressividade do isolado produtor de elevadas quantidades de concanamicinas apenas sobre os cultivares Mondial, Monalisa e Asterix. Por sua vez, os resultados da avaliação do nível de resistência ao patógeno demonstraram que os cultivares Monalisa, Ágata, Asterix e Cupido são suscetíveis e os cultivares Atlantic e Mondial mostraram-se resistentes aos dois isolados de Streptomyces spp. avaliados. Por outro lado, a fitotoxina taxtomina A é a toxina mais frequentemente produzida pelas espécies fitopatogênicas de Streptomyces spp. O estudo do mecanismo de ação desta fitotoxina poderá auxiliar no entendimento de sua contribuição no desenvolvimento da doença. A taxtomina A é uma fitotoxina não específica e causa efeitos semelhantes em plantas de diferentes famílias botânicas. Desta forma, modificações citológicas, ultraestruturais e bioquímicas induzidas pela taxtomina A foram analisadas em plântulas de sorgo. Os tecidos foram tratados com taxtomina A e avaliados após sete dias do tratamento. Observou-se desorganização em todas as células dos tecidos tratados com a taxtomina A. A membrana plasmática das células do mesofilo foliar foi retraída e destacada da parede celular em diversos pontos. Entretanto, o plasmalema não pareceu rompido. O efeito sobre a permeabilidade seletiva da membrana plasmática também foi avaliado bioquimicamente, onde foi observado aumentos na saída de eletrólitos. Os cloroplastos apresentaram deformações na superfície e perda de turgidez. Estas deformações provavelmente contribuíram para a redução do teor de clorofilas A e B. As plântulas também apresentaram elevado acúmulo de fitoalexinas do tipo deoxiantocianidinas. Desta forma, conclui-se que a taxtomina A age principalmente sobre a membrana plasmática e organelas membranosas. Em contrapartida, o acúmulo de fitoalexinas evidencia que concentrações mínimas desta toxina podem ser exploradas como eliciador da resposta de defesa em plantas. / The genus Streptomyces is a different prokaryote phytopathogen group, being morphologically similar to fungi and able to produce several important secondary metabolites. The potato common scabies is the main plant disease caused by the members of the genus. The main causal agent of the plant disease, Streptomyces scabies, is able to produce the phytoxins concanamycins. However, the importance of these toxins in the aggressiveness of S. scabies strains was not proven. This research aimed to evaluate the reaction of main potato cultivars used in Brazil to Streptomyces spp. strains, exhibiting different levels of concanamycins production. The toxin production by several strains was quantified by high performance liquid chromatography (HPLC) and two strains (higher and lower producers) were chosen and used for resistance evaluation of six potato cultivars under greenhouse. Pots containing sterile substratum received a suspension of bacterial spores and the healthy seed tubers at the same time. After four months, the level of disease was evaluated and the results showed increasing in aggressiveness for the higher concanamycins producer only in the Mondial, Monalisa and Asterix cultivars. For the two strains, the cultivars Atlantic and Mondial were resistant and the cultivars Monalisa, Cupido, Ágata and Asterix were susceptible. On the other hand, the thaxtomin A is the main phytotoxin of plant pathogenic Streptomyces spp. Therefore, the study of the thaxtomin A action mechanism is important to explain its contribution to disease development. The thaxtomin A is not a specific toxin and causes similar effect in several plants of different botanical families. Thus, the cytological, ultrastructural and biochemical modifications induced by thaxtomin A were evaluated in sorghum seedlings. Leaf tissues of seedlings were treated with high levels of thaxtomin A and evaluated 7 days after treatment. Cytological disorganization was observed in all treated cells. The plasmma membrane of the cells of immature leaves was detached from the wall in several places. However, plasmmalema did not seem degraded. The chloroplasts had showed significant deformations in the surface and volume reduction. Theses changes in chloroplasts probably contributed for the reduction of chlorophylls A and B levels. The sorghum seedlings also showed high phytoalexin accumulation (deoxiantocianydins) in response to thaxtomin A treatment. Thus, the thaxtomin A acts mainly on plasmma membrane and membranous organelles, causing plasmolises, cell disorganization, deformations in chloroplasts and chlorophyll reduction in sorghum seedlings. Finally, the accumulation of phytoalexins in response to thaxtomin A treatment points out it potential to induce resistance in plants.

The dissertation presents theoretical and experimental studies on the physical origin of the signal in photothermal microscopy of single particles. This noninvasive optical far field microscopy scheme allows the imaging and detection of single absorbing nanoparticles. Based on a heat-induced pertur- bation in the refractive index in the embedding medium of the nanoscopic absorber, a corresponding probe beam modification is measured and quantified. The method is well established and has been applied since its first demonstration in 2002 to the imaging and characterization of various absorbing particle species, such as quantum dots, single molecules and nanoparticles of different shapes. The extensive theoretical developments presented in this thesis provide the first quantitative assess- ment of the signal and at the same time enlarge its phenomenology and thereby its potential. On the basis of several approximation schemes to the Maxwell equations, which fundamentally gov- ern the interaction of light with inhomogeneities, several complementing models are devised which describe the photothermal signal both qualitatively and quantitatively. In succession an interdepen- dent and self-consistent set of theoretical descriptions is given and allows important experimental consequences to be drawn. In consequence, the photothermal signal is shown to correspond to the action of a nanoscopic (thermal) lens, represented by the spherically symmetric refractive index pro- file n(r) which accompanies the thermal expansion of the absorber’s environment. The achieved quantification allows the direct measurement of absorption cross-sections of nanoparticles. Further, a qualitatively new phenomenology of the signal is unraveled and experimentally demonstrated. The separate roles of the probing and the heating beams in photothermal microscopy is dismantled and the influence of their relative alignment shown to allow for a controlled adjustment of the effective detection volume. For the first time, both positive and negative signals are demonstrated to occur and to be the characteristic signature of the lens-like action on the probe beam. The detection of the probe beam’s modification is also shown to sensitively depend on the aperture used in the detection chan- nel, and a signal optimization is shown to be feasible. Also, a generalization of the detectable signal via the use of a quadrant photodiode is achieved. Specifically, measuring the far field beam deflec- tion the result of the beam passing the lens off-center manifests in a laterally split detection volume. Hereby, finally each classical photothermal spectroscopic techniques has been shown to possess its microscopic counterpart. Central to the understanding of this generalized and new phenomenology is a scalar wave-optical model which draws an analogy between the scattering of a massive particle wave-packet by a Coulomb potential and the deflection of a focused beam by a photonic potential connected with the thermal lens. The significance of the findings is demonstrated by its methodological implications on photother- mal correlation spectroscopy in which the diffusion dynamics of absorbing colloidal particles can be studied. The unique split focal detection volumes are shown to allow the sensitive measurement of a deterministic velocity field. Finally, the method is supplemented by a newly introduced sta- tistical analysis method which is capable of characterizing samples containing a heterogeneous size distribution.

O gênero Streptomyces constitui-se em um grupo diferenciado de procariotos fitopatogênicos, por serem morfologicamente similares aos fungos e produzirem diversos importantes metabólitos secundários. A sarna comum da batata é principal doença causada pelo gênero. O principal agente causal da doença, Streptomyces scabies, produz fitotoxinas denominadas concanamicinas, porém, não foi comprovada a importância da produção das mesmas na agressividade dos isolados de S. scabies. Dessa forma, neste trabalho procurouse avaliar a reação dos cultivares mais plantados no Brasil a isolados de S. scabies exibindo diferentes níveis de produção de concanamicinas. O nível de produção de concanamicinas A e B de dez isolados de Streptomyces spp. foi avaliado por cromatografia líquida de alta pressão (HPLC) e dois isolados (produtor de alto nível da toxina; baixo produtor) foram selecionados e utilizados na avaliação da resistência de seis cultivares de batata em casa de vegetação. Vasos contendo o substrato esterilizado receberam a suspensão de esporos bacterianos junto com os tubérculos sadios no momento do plantio e após quatro meses, a severidade da doença foi avaliada. Os resultados demonstraram aumento na agressividade do isolado produtor de elevadas quantidades de concanamicinas apenas sobre os cultivares Mondial, Monalisa e Asterix. Por sua vez, os resultados da avaliação do nível de resistência ao patógeno demonstraram que os cultivares Monalisa, Ágata, Asterix e Cupido são suscetíveis e os cultivares Atlantic e Mondial mostraram-se resistentes aos dois isolados de Streptomyces spp. avaliados. Por outro lado, a fitotoxina taxtomina A é a toxina mais frequentemente produzida pelas espécies fitopatogênicas de Streptomyces spp. O estudo do mecanismo de ação desta fitotoxina poderá auxiliar no entendimento de sua contribuição no desenvolvimento da doença. A taxtomina A é uma fitotoxina não específica e causa efeitos semelhantes em plantas de diferentes famílias botânicas. Desta forma, modificações citológicas, ultraestruturais e bioquímicas induzidas pela taxtomina A foram analisadas em plântulas de sorgo. Os tecidos foram tratados com taxtomina A e avaliados após sete dias do tratamento. Observou-se desorganização em todas as células dos tecidos tratados com a taxtomina A. A membrana plasmática das células do mesofilo foliar foi retraída e destacada da parede celular em diversos pontos. Entretanto, o plasmalema não pareceu rompido. O efeito sobre a permeabilidade seletiva da membrana plasmática também foi avaliado bioquimicamente, onde foi observado aumentos na saída de eletrólitos. Os cloroplastos apresentaram deformações na superfície e perda de turgidez. Estas deformações provavelmente contribuíram para a redução do teor de clorofilas A e B. As plântulas também apresentaram elevado acúmulo de fitoalexinas do tipo deoxiantocianidinas. Desta forma, conclui-se que a taxtomina A age principalmente sobre a membrana plasmática e organelas membranosas. Em contrapartida, o acúmulo de fitoalexinas evidencia que concentrações mínimas desta toxina podem ser exploradas como eliciador da resposta de defesa em plantas. / The genus Streptomyces is a different prokaryote phytopathogen group, being morphologically similar to fungi and able to produce several important secondary metabolites. The potato common scabies is the main plant disease caused by the members of the genus. The main causal agent of the plant disease, Streptomyces scabies, is able to produce the phytoxins concanamycins. However, the importance of these toxins in the aggressiveness of S. scabies strains was not proven. This research aimed to evaluate the reaction of main potato cultivars used in Brazil to Streptomyces spp. strains, exhibiting different levels of concanamycins production. The toxin production by several strains was quantified by high performance liquid chromatography (HPLC) and two strains (higher and lower producers) were chosen and used for resistance evaluation of six potato cultivars under greenhouse. Pots containing sterile substratum received a suspension of bacterial spores and the healthy seed tubers at the same time. After four months, the level of disease was evaluated and the results showed increasing in aggressiveness for the higher concanamycins producer only in the Mondial, Monalisa and Asterix cultivars. For the two strains, the cultivars Atlantic and Mondial were resistant and the cultivars Monalisa, Cupido, Ágata and Asterix were susceptible. On the other hand, the thaxtomin A is the main phytotoxin of plant pathogenic Streptomyces spp. Therefore, the study of the thaxtomin A action mechanism is important to explain its contribution to disease development. The thaxtomin A is not a specific toxin and causes similar effect in several plants of different botanical families. Thus, the cytological, ultrastructural and biochemical modifications induced by thaxtomin A were evaluated in sorghum seedlings. Leaf tissues of seedlings were treated with high levels of thaxtomin A and evaluated 7 days after treatment. Cytological disorganization was observed in all treated cells. The plasmma membrane of the cells of immature leaves was detached from the wall in several places. However, plasmmalema did not seem degraded. The chloroplasts had showed significant deformations in the surface and volume reduction. Theses changes in chloroplasts probably contributed for the reduction of chlorophylls A and B levels. The sorghum seedlings also showed high phytoalexin accumulation (deoxiantocianydins) in response to thaxtomin A treatment. Thus, the thaxtomin A acts mainly on plasmma membrane and membranous organelles, causing plasmolises, cell disorganization, deformations in chloroplasts and chlorophyll reduction in sorghum seedlings. Finally, the accumulation of phytoalexins in response to thaxtomin A treatment points out it potential to induce resistance in plants.

The dissertation presents theoretical and experimental studies on the physical origin of the signal in photothermal microscopy of single particles. This noninvasive optical far field microscopy scheme allows the imaging and detection of single absorbing nanoparticles. Based on a heat-induced pertur- bation in the refractive index in the embedding medium of the nanoscopic absorber, a corresponding probe beam modification is measured and quantified. The method is well established and has been applied since its first demonstration in 2002 to the imaging and characterization of various absorbing particle species, such as quantum dots, single molecules and nanoparticles of different shapes. The extensive theoretical developments presented in this thesis provide the first quantitative assess- ment of the signal and at the same time enlarge its phenomenology and thereby its potential. On the basis of several approximation schemes to the Maxwell equations, which fundamentally gov- ern the interaction of light with inhomogeneities, several complementing models are devised which describe the photothermal signal both qualitatively and quantitatively. In succession an interdepen- dent and self-consistent set of theoretical descriptions is given and allows important experimental consequences to be drawn. In consequence, the photothermal signal is shown to correspond to the action of a nanoscopic (thermal) lens, represented by the spherically symmetric refractive index pro- file n(r) which accompanies the thermal expansion of the absorber’s environment. The achieved quantification allows the direct measurement of absorption cross-sections of nanoparticles. Further, a qualitatively new phenomenology of the signal is unraveled and experimentally demonstrated. The separate roles of the probing and the heating beams in photothermal microscopy is dismantled and the influence of their relative alignment shown to allow for a controlled adjustment of the effective detection volume. For the first time, both positive and negative signals are demonstrated to occur and to be the characteristic signature of the lens-like action on the probe beam. The detection of the probe beam’s modification is also shown to sensitively depend on the aperture used in the detection chan- nel, and a signal optimization is shown to be feasible. Also, a generalization of the detectable signal via the use of a quadrant photodiode is achieved. Specifically, measuring the far field beam deflec- tion the result of the beam passing the lens off-center manifests in a laterally split detection volume. Hereby, finally each classical photothermal spectroscopic techniques has been shown to possess its microscopic counterpart. Central to the understanding of this generalized and new phenomenology is a scalar wave-optical model which draws an analogy between the scattering of a massive particle wave-packet by a Coulomb potential and the deflection of a focused beam by a photonic potential connected with the thermal lens. The significance of the findings is demonstrated by its methodological implications on photother- mal correlation spectroscopy in which the diffusion dynamics of absorbing colloidal particles can be studied. The unique split focal detection volumes are shown to allow the sensitive measurement of a deterministic velocity field. Finally, the method is supplemented by a newly introduced sta- tistical analysis method which is capable of characterizing samples containing a heterogeneous size distribution.:Contents Bibliographic description Abbreviations 1 Introduction 2 Theoretical Background 2.1 The current literature on the subject of the photothermal signal 2.2 Thermal conduction, and the temperature field around heated nanoparticles 2.3 The linear thermo-refractive response and the thermal lens 2.4 MAXWELL equations and approximation schemes 2.4.1 The MAXWELL equations 2.4.2 HELMHOLTZ equations 2.4.3 Paraxial HELMHOLTZ equation for the field components 2.4.4 Geometrical optics and the eikonal ansatz 2.5 Diffraction and the optical resolution limit in far field microscopy 2.5.1 Transmission scanning microscopy 2.5.2 Point spread functions and aberrations 2.5.3 Scalar diffraction approximation for weakly focused beams 2.5.4 Vectorial diffraction for highly focused electromagnetic fields 2.5.5 Theoretical description of transmission signals 2.6 Elastic scattering of light 2.6.1 Overview of optical elastic scattering theory 2.6.2 The integral equation of potential scattering and the BORN approximation 2.6.3 The generalized LORENZ-MIE theory 2.6.4 The electromagnetic fields 2.6.5 Description of the incident field: beam shape coefficients 2.6.6 Multilayered scatterers 2.6.7 POYNTING vector and field decomposition 2.6.8 Energy balance & total cross-sections 2.6.9 Optical theorem & the extinction paradox 2.6.10 Small particle scattering: the RAYLEIGH-limit 2.7 Optical properties of gold nanoparticles & Surface plasmon resonances 2.7.1 Dielectric function of gold 2.7.2 Total cross-sections of plasmonic nanoparticles properties of gold nanoparticles & Surface plasmon resonances 2.8 (Hot) BROWNian motion, diffusion and their statistical analysis 2.8.1 (Hot) BROWNian motion 2.8.2 Diffusion and correlation analysis 2.8.3 Methods regarding the signal statistics of diffusing tracer particles 2.9 RUTHERFORD scattering of charged particles 2.9.1 Classical RUTHERFORD scattering 2.9.2 Quantum mechanical COULOMB scattering 3 Experimental Setup 3.1 Sample preparation 3.2 Photothermal microscopy setup 4 Photothermal Imaging: Results and Discussion 4.1 MAXWELL equations: Exact treatment of the PT signal 4.1.1 Angularly resolved powers: Fractional cross-sections 4.1.2 Incident power and background normalization 4.1.3 Fractional scattering and extinction cross-sections (off-axis) 4.1.4 Fractional scattering and extinction cross-sections (on-axis) 4.1.5 Small particle approximation(on-axis) 4.1.6 General properties of transmission scans 4.1.7 The thermal lens n(r) in the MIE-scattering framework 4.1.8 The photothermal signal F in the MIE scattering framework 4.2 Geometrical optics: Photonic RUTHERFORD scattering (ray optics) 4.2.1 FERMAT’s principle for a thermal lens medium 4.2.2 Gaussian beam transformation by a thermal lens 4.2.3 Experiments using weakly focused, i.e. nearly Gaussian beams 4.3 HELMHOLTZ equation: Photonic RUTHERFORD scattering (wave optics) 4.3.1 Plane-wave scattering 4.3.2 Focused beam scattering 4.3.3 Connection to the far field 4.3.4 Photothermal Rutherford scattering microscopy 4.3.5 Photothermal half-aperture measurements 4.4 Paraxial HELMHOLTZ equation: FRESNEL diffraction by a thermal lens 4.4.1 The diffraction integral and the phase mask for a thermal lens 4.4.2 The photothermal signal expressed via the image plane field 4.4.3 Experimental demonstration of the signal inversion 4.4.4 Connection to photothermal RUTHERFORD scattering 4.5 Plane-wave extinction & scattering by a thermal lens 4.5.1 The BORN approximation for the ideal and time-dependent thermal lens 4.5.2 The eikonal approximation for the ideal thermal lens and x>>1 4.5.3 Lessons to be learned from plane-wave scattering by thermal lenses 4.6 What is a lens? And is n(r) a lens? 5 Methodological Applications of the Results 5.1 Generalized photothermal correlation spectroscopy (incl. twin-PhoCS) 5.2 Photothermal signal distribution analysis (PhoSDA) 6 Summary and Outlook 6.1 Summary of the results 6.2 Outlook 7 Appendix 7.1 Material parameters 7.2 Calculation parameters 7.3 Interactive simulation scripts (Processing) 7.4 Vectorial scattering in the BORN-approximation 7.5 Details regarding the scattering framework 7.5.1 Connection between Gmn,TE,TM of Ref.1 and gmn,TE,TM in the GLMT 7.5.2 Off-axis BSCs including aberration (single interface) 7.5.3 Details on the incidence power Pinc 7.5.4 Details on the incidence power Pinc for arbitrary beams 7.5.5 Explicit expressions for the spherical field components of Es,i and Hs,i 7.5.6 Note on the time-dependence and the corresponding sign-conventions in M 7.5.7 Recurrence relation for Pn and tn 7.5.8 Gaussian beam shape coefficients: Off-axis 7.5.9 Multilayered Scatterer 7.5.10 POYNTING-vector and energy flow fields 7.5.11 Convergence 7.5.12 Further evaluations in the GLMT framework 7.5.13 Diffraction model: Comparison of angular PT signal pattern to the GLMT 7.6 Details on geometrical optics models 7.6.1 Geometrical optics: Exact solution r(f) for |bx|<1 7.6.2 Correspondences in photonic and partile RUTHERFORD scattering 7.6.3 On the difference in the definition of optical energy 7.6.4 Ray-opticsphotothermalsignal 7.6.5 Thick lens raytracing and the equivalent lens shape for a given aberration 7.7 Thermal lens around a wire of radius R 7.8 Twin-PhoCS: Graphic illustration of the CCF integrand Curriculum Vitae Publications Declaration Acknowledgements List of Tables List of Figures Bibliography

Depuis l'invention du transistor MOS à effet de champ dans les années 60, l'exploitation de cette brique élémentaire a permis une évolution exponentielle du domaine de la microélectronique, avec une course effrénée vers la miniaturisation des dispositifs électroniques CMOS. Dans ce contexte, l'introduction des oxydes "high-κ" (notamment HfO2) a permis de franchir la barrière sub-nanométrique de l'EOT (Equivalent Oxide Thickness) pour l’oxyde de grille. Les travaux actuels concernent notamment la recherche de matériaux "high-κ" et de procédés qui permettraient d'avoir une interface abrupte, thermodynamiquement stable avec le silicium, pouvant conduire à des EOTs de l'ordre de 5Å. L’objectif de cette thèse, était d’explorer le potentiel de l’oxyde LaAlO3 amorphe déposé sur silicium par des techniques d’Épitaxie par Jets Moléculaires, en combinant des études sur les propriétés physico-chimiques et électriques de ce système. Le travail de thèse a d’abord consisté à définir des procédures d'élaboration sur Si de couches très minces (≈4nm), robustes et reproductibles, afin de fiabiliser les mesures électriques, puis à optimiser la qualité électrique des hétérostructures en ajustant les paramètres de dépôt à partir de corrélations entre résultats électriques et propriétés physico-chimiques (densité, stœchiométrie, environnement chimique…) et enfin à valider un procédé d'intégration du matériau dans la réalisation de MOSFET. La stabilité et la reproductibilité des mesures ont été atteintes grâce à une préparation de surface du substrat adaptée et grâce à l'introduction d'oxygène atomique pendant le dépôt de LaAlO3, permettant ainsi une homogénéisation des couches et une réduction des courants de fuite. Après optimisation des paramètres de dépôt, les meilleures structures présentent des EOTs de 8-9Å, une constante diélectrique de 16 et des courants de fuite de l'ordre de 10-2A/cm². Les caractérisations physico-chimiques fines des couches par XPS ont révélé des inhomogénéités de composition qui peuvent expliquer que le κ mesuré soit inférieur aux valeurs de LaAlO3 cristallin (20-25). Bien que les interfaces LAO/Si soient abruptes après le dépôt et que LaAlO3 soit thermodynamiquement stable vis-à-vis du silicium, le système LAO amorphe /Si s’est révélé instable pour des recuits post-dépôt effectués à des températures supérieures à 700°C. Un procédé de fabrication de MOSFETs aux dimensions relâchées a été défini pour tester les filières high-κ. Les premières étapes du procédé ont été validées pour LaAlO3. / Since MOS Field Effect Transistor invention in the 60's, the exploitation of this elementary piece of technology allowed an exponential evolution in the microelectronic field, with a frantic race towards miniaturization of CMOS electronic devices. In this context, the introduction of "high-κ" oxides (notably HfO2) allowed to cross the sub-nanometer barrier of EOT (Equivalent Oxide Thickness) for the gate oxide. Current work are notably related to "high-κ" research materials and processes that would allow an abrupt and thermodynamically stable interface with respect to silicon, that may lead to EOTs of about 5Å. The purpose of this thesis was to explore the potential of amorphous oxide LaAlO3 deposited on silicon by techniques of molecular beam epitaxy, combining studies of the physicochemical and electrical properties of this system. The thesis work has first consisted in defining procedures for the preparation of very thin (≈ 4 nm), robust and reproducible layers on Si in order to allow reliable electrical measurements then to optimize the electrical quality of the hetero-structures by adjusting deposition parameters from correlations between electrical results and physicochemical properties (density, stoichiometry, chemical environment...) and finally to validate a method for integrating the material in the realization of MOSFET. The stability and reproducibility of the measurements were achieved thanks to an adapted surface preparation of the substrate and by the introduction of atomic oxygen during the LaAlO3 deposition, thus allowing homogenization of layers and reducing leakage currents. After optimizing the deposition parameters, the best structures exhibit EOTs of 8-9 A, a dielectric constant of 16 and leakage currents in the range of 10-2 A/cm². Accurate physico-chemical characterizations of thin layers by XPS revealed composition inhomogeneities that can explain why the measured κ is less than values of crystalline LaAlO3 (20-25). Although the LAO/Si interfaces are steep after deposition and LaAlO3 is thermodynamically stable with respect to the silicon, amorphous system LAO/Si has proven unstable during post-deposition annealing carried out at temperatures above 700 ° C. A process for producing MOSFETs with released dimensions was defined to test high-κ field. The first stages of the process have been validated for LaAlO3.