Orientador: Newton Cesario Frateschi / Tese (doutorado) - Universidade Estaual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-23T21:02:10Z (GMT). No. of bitstreams: 1 Vallini_Felipe_D.pdf: 6501837 bytes, checksum: 9c23f9afa5633adc0e7fa246e3bcafc5 (MD5) Previous issue date: 2013 / Resumo: Neste trabalho são investigados os nanolasers de semicondutor do tipo metálico-dielétrico com injeção eletrônica. Com o uso de softwares robustos otimizamos as propriedades eletromagnéticas das cavidades propostas através da solução das equações de Maxwell em um meio material. Também resolvemos auto-consistentemente as equações de Poisson, de continuidade, de transporte e de Schroedinger para obter as propriedades eletrônicas da cavidade. Tal otimização, considerando a parte de confinamento do modo em conjunto com a parte da injeção eletrônica nunca havia sido proposta ou realizada para nanolasers. Estudamos o efeito do meio de ganho em um nanolaser desse tipo através da comparação do desempenho de um nanolaser com meio de ganho bulk e outro com meio de ganho de múltiplos poços quânticos. Essa análise foi feita inserindo um modelo de reservatório de portadores às equações de taxa convencionais para nanolasers. Fabricamos dois nanolasers, um com cada meio de ganho. Os nanolasers foram caracterizados e demonstramos que um meio de ganho bulk é mais adequado ao desenvolvimento de nanolasers de semicondutor metálico-dielétrico com bombeio eletrônico. Por fim, medimos um nanolaser com meio de ganho bulk a 77 K, o qual apresentou uma corrente de limiar da ordem de 2 mA, emissão em 1567 nm e largura de linha de 0.4 nm / Abstract: In this work we have investigated metallo-dielectric semiconductor nanolasers with electronic pumping. We have optimized the electromagnetic properties of the proposed cavities through the solution of Maxwell equations in a material media using robust software. We also solved self-consistently Poisson, continuity, transport and Schrodinger equations to obtain the electronic properties of the cavities. Such optimization, which considers the optical mode confinement together with the electronic injection, had not been proposed or realized for nanolasers yet. We have studied the effect of the gain media in this class of nanolaser comparing the performance of a nanolaser with bulk gain media and a nanolaser with multiple quantum wells gain media. This analysis was done inserting a reservoir model for carriers into conventional laser rate equations. We have fabricated two nanolasers, each one with one of the proposed gain media. The nanolasers were measured and we demonstrated that a bulk gain media is more suitable for the development of metallo-dielectric semiconductor nanolasers with electronic pumping. Finally, we have measured a bulk gain media nanolaser at 77 K, with a threshold current of 2 mA, emission at 1567 nm and a linewidth of 0.4 nm / Doutorado / Física / Doutor em Ciências

Silver (Ag) is an ideal low-loss platform for plasmonic applications, but from a materials standpoint it presents challenges. Development of plasmonic devices based on Ag thin film has been hindered both by the dificulty of fabricating such film and by its fragility out of vacuum. Silver is non-wetting on semiconducting and insulating substrates, but on certain semiconductors and insulators can adopt a metastable atomically at epitaxial film morphology if it is deposited using the "two-step" growth method. This method consists of deposition at low temperature and annealing to room temperature. However, epitaxial Ag is metastable, and dewets out of vacuum. The mechanisms of dewetting in this system remain little understood. The fragility of Ag film presents a particular problem for the engineering of plasmonic devices, which are predicted to have important industrial applications if robust low-loss platforms can be developed. This dissertation presents two sets of experiments. In the first set, scanning probe techniques and low energy electron microscopy have been used to characterize Ag(111) growth and dewetting on two orientations of silicon (Si), Si(111) and Si(100). These studies reveal that multiple mechanisms contribute to Ag film dewetting. Film stability is observed to increase with thickness, and thickness to play a decisive role in determining dewetting processes. A method has been developed to cap Ag film with germanium (Ge) to stabilize it against dewetting. The second set of experiments consists of optical studies that focus on the plasmonic properties of epitaxial Ag film. Because of the problems posed until now by epitaxial Ag growth and stabilization, research and development in the area of plasmonics has been limited to devices based on rough, thermally evaporated Ag film, which is robust and simple to produce. However, plasmonic damping in such film is higher than in epitaxial film. The optical studies presented here establish that Ag film can now be stabilized sufficiently to allow optical probing and device applications out of vacuum. Furthermore, they demonstrate the superiority of epitaxial Ag film relative to thermally evaporated film as a low-loss platform for plasmonic devices spanning the visible and infrared regimes. / text

La photonique sur silicium constitue une plateforme idéale pour transmettre et distribuer des signaux optiques au sein d'une puce et sur de longues distances sans pertes excessives. L'intégration de semiconducteurs III-V sur des circuits photonique en silicium est un projet excitant mais ambitieux, que nous avons mené en combinant le meilleur de l'optoélectronique des semiconducteurs III-V et des technologies photonique en siliicium-sur-isolant (SOI en anglais). Afin de pouvoir remplacer les interconnexions metalliques existantes par des interconnexion optiques, nous nous sommes efforcés d'utiliser les objets ayant les dimensions les plus petites et consommant les plus petites énergies comme peuvent l'être les nanocavités en Cristaux Photoniques incorporant des matériaux actifs en III-V. Cette thèse visait à conceptualiser, fabriquer et étudier expérimentalement des structures hybrides III-V/circuit photonique SOI, où une couche de III-V, reportée par collage adhésif à quelques centaines de nm du silicium, est gravée en une cavité optique de type cristal photonique " nanobeam " et résonante autour de 1.5 μm. Les principaux résultats de ce travail sont les démonstration 1) d'une efficacité de couplage entre la cavité et le guide d'onde SOI facilement ajustable, pouvant excéder 90% lorsque les conditions d'accord de phase sont remplies, 2) de l'émission laser en régime continue avec des puits quantiques via la passivation des surfaces, et 3) d'une mémoire optique de durée supérieure à 2s avec des énergies de commutations ultrafaibles (~0.4 fJ). Nous présentons aussi un modèle pour fabriquer des cavités " nanobeam " de facteurs Q très élevés, encapsulées dans un matériau bas indice.