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Resource and thermal management in 3D-stacked multi-/many-core systemsZhang, Tiansheng 10 March 2017 (has links)
Continuous semiconductor technology scaling and the rapid increase in computational needs have stimulated the emergence of multi-/many-core processors. While up to hundreds of cores can be placed on a single chip, the performance capacity of the cores cannot be fully exploited due to high latencies of interconnects and memory, high power consumption, and low manufacturing yield in traditional (2D) chips. 3D stacking is an emerging technology that aims to overcome these limitations of 2D designs by stacking processor dies over each other and using through-silicon-vias (TSVs) for on-chip communication, and thus, provides a large amount of on-chip resources and shortens communication latency. These benefits, however, are limited by challenges in high power densities and temperatures.
3D stacking also enables integrating heterogeneous technologies into a single chip. One example of heterogeneous integration is building many-core systems with silicon-photonic network-on-chip (PNoC), which reduces on-chip communication latency significantly and provides higher bandwidth compared to electrical links. However, silicon-photonic links are vulnerable to on-chip thermal and process variations. These variations can be countered by actively tuning the temperatures of optical devices through micro-heaters, but at the cost of substantial power overhead.
This thesis claims that unearthing the energy efficiency potential of 3D-stacked systems requires intelligent and application-aware resource management. Specifically, the thesis improves energy efficiency of 3D-stacked systems via three major components of computing systems: cache, memory, and on-chip communication. We analyze characteristics of workloads in computation, memory usage, and communication, and present techniques that leverage these characteristics for energy-efficient computing.
This thesis introduces 3D cache resource pooling, a cache design that allows for flexible heterogeneity in cache configuration across a 3D-stacked system and improves cache utilization and system energy efficiency. We also demonstrate the impact of resource pooling on a real prototype 3D system with scratchpad memory.
At the main memory level, we claim that utilizing heterogeneous memory modules and memory object level management significantly helps with energy efficiency. This thesis proposes a memory management scheme at a finer granularity: memory object level, and a page allocation policy to leverage the heterogeneity of available memory modules and cater to the diverse memory requirements of workloads.
On the on-chip communication side, we introduce an approach to limit the power overhead of PNoC in (3D) many-core systems through cross-layer thermal management. Our proposed thermally-aware workload allocation policies coupled with an adaptive thermal tuning policy minimize the required thermal tuning power for PNoC, and in this way, help broader integration of PNoC. The thesis also introduces techniques in placement and floorplanning of optical devices to reduce optical loss and, thus, laser source power consumption. / 2018-03-09T00:00:00Z
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All-optical manipulation of photonic membranesKirkpatrick, Blair Connell January 2017 (has links)
Optical tweezers have allowed us to harness the momentum of light to trap, move, and manipulate microscopic particles with Angstrom-level precision. Position and force feedback systems grant us the ability to feel the microscopic world. As a tool, optical tweezers have allowed us to study a variety of biological systems, from the mechanical properties of red blood cells to the quantised motion of motor-molecules such as kinesin. They have been applied, with similar impact, to the manipulation of gases, atoms, and Bose-Einstein condensates. There are, however, limits to their applicability. Historically speaking, optical tweezers have only been used to trap relatively simple structures such as spheres or cylinders. This thesis is concerned with the development of a fabricational and optical manipulation protocol that allows holographical optical tweezers to trap photonic membranes. Photonic membranes are thin, flexible membranes, that are capable of supporting nanoplasmonic features. These features can be patterned to function as metamaterials, granting the photonic membrane the ability to function as almost any optical device. It is highly desirable to take advantage of these tools in a microfluidic environment, however, their extreme aspect ratios mean that they are not traditionally compatible with the primary technology of microfluidic manipulation: optical tweezers. In line with recent developments in optical manipulation, an holistic approach to optical trapping is used to overcome these limitations. Full six-degree-of-freedom control over a photonic membrane is demonstrated through the use of holographical optical tweezers. Furthermore, a photonic membrane (PM)-based surface-enhanced Raman spectroscopy sensor is presented which is capable of detecting rhodamine dye from a topologically undulating sample. This work moves towards marrying these technologies such that photonic membranes, designed for bespoke applications, can be readily deployed into a microfluidic environment. Extending the range of tools available in the microfluidic setting helps pave the way toward the next set of advances in the field of optical manipulation.
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Filmes finos híbridos orgânicos-inorgânicos para fotônicaOliveira, Daniela Coelho de [UNESP] 16 June 2006 (has links) (PDF)
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oliveira_dc_dr_araiq.pdf: 3933489 bytes, checksum: a5dad8dc37a7fbb9d8a4df2c0eb00150 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O material estudado neste trabalho é um híbrido orgânico-inorgânico denominado di-ureasil formado por uma cadeia tipo poliéter unida em ambas extremidades a um grupo siloxano por pontes de uréia. As curvas de SAXS mostram um pico de interferência característico, atribuído a uma correlação espacial existente entre as partículas de siloxanos. Um complexo formado entre zircônio e ácido metacrílico foi adicionado ao material base e o aumento do teor deste complexo leva a um alargamento das bandas e um deslocamento de q para valores maiores. O alargamento é devido ao aumento na dispersão das distâncias interpartículas e o deslocamento pode ser devido a interação do zicônio com a região polimérica levando a uma diminuição das distâncias entre as partículas de siloxanos. As mesmas informações podem ser obtidas a partir das curvas de difração de raios X. A desconvolução gaussiana das curvas experimentais indica a formação de nanodomínios de óxido de zircônio. As curvas de transmissão na região do infravermelho mostram a interação dessas espécies de zircônio com a região polimérica da matriz híbrida. Entretanto, a competição pela água do meio reacional entre espécies de Zr e Si levam a uma diminuiçào no grau de condensação das espécies de siloxano evidenciada pelo aparecimento de bandas relativas a silanóis residuais apenas para amostras com alta concentração de zircônio. Este fato é confirmado pelas análises de RMN de 29Si. As propriedades ópticas dos di-ureasis também foram estudadas. Uma banda larga de emissão que cobre a parte do visível do espectro eletromagnético é devida à combinação de duas componentes atribuídas à processos de recombinação doador-aceptor, que ocorre entre grupos NH das ligações uréia e nos centros de siloxanos. / The base material studied is the organic-inorganic host termed di-ureasil formed by poly(ether)-based chains grafted at both ends to a siloxone backbone through urea cross linkages. SAXS curves display a characteristic interference peak attributed to the spatial correlation between siloxane nanoparticles. A methacrylate modified zirconium alcoxide (Zr- AMA) was added to this base host and the increasing addition leads to broadening and q shift to higher values. Broadening is due to increasing dispersion in the interparticle distances and the shift could be due to zirconium interaction with the polymeric part leading decreasing distances between siloxane particles. Essentially the same information is obtained from XRD curves. Gaussian deconvolution of the experimental curves indicate the formation of zirconium oxide based nanodomains. FT-IR spectra analysis have shown the interaction of the zirconium based species with the polymeric part of the hybrid host. Moreover competition for water between Si and Zr species lead to decrease on the condensation degree of siloxane species as evidenced by the appearence of characteristic silanol bands only for higher Zr content. This fact is confirmed by 29Si NMR. The optical properties of the di-ureasils were also studied. A broad emission band covering the visible part of the electromagnetic spectrum is attributed to the convolution of two components assigned to radiative recombination processes typical of donor-acceptor pairs occurring in the NH groups of the urea cross-links and in the siliceous nanodomains. With the addition of Zr-AMA broadening is observed. Luminescence spectroscopy shows that the addition of highly emitting Eu3+ â -diketonate complex [Eu(tta)3(H2O)2] (where tta stands for thenoiltrifluoribetadiketonate) to the di-ureasil host has lead to interesting features.
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Intégration en technologie CMOS d'un modulateur plasmonique à effet de champ CMOS Integration of a field effect plasmonic modulator / CMOS Integration of field effect plasmonic modulatorsEmboras, Alexandros 10 May 2012 (has links)
Dans la réalisation de circuits intégrés hybrides électroniques - photoniques pour les réseaux télécom, les modulateurs intégrés plasmoniques pourront jouer un role essentiel de codage de l'information en signaux optiques. Cette thése montre la réalisation d'une approche modulateur plasmonique a effet de champ, intégrée en silicium en utilisant les technologies CMOS standards. Ce modulateur MOS plasmonique présente diverses propriétés intéressantes, a savoir un confinement optique fort, permettant une augmentation de l'interaction lumiére matiére. Ces modulateurs plasmoniques permettent aussi de réduire l'inadéquation entre la taille des dispositifs en photonique Si et celle de l' électronique, ce qui permet d'envisager une convergence de leur fabrication en technologie VLSI sur une meme puce. Le modulateur étudié dans ce mémoire repose sur l'accumulation de porteurs dans un condensateur MOS a grille cuivre integer dans un guide d'onde en silicium, nécessitant aux technologies front end et back end Cu d etre combinés de quelques nanométres l'une de l'autre. Nous présentons aussi de nouveaux designs pour injecter de la lumiére a partir de guide d'onde SOI dans un guide a nanostructure plasmonique et les mesures d'une modulation électro-optique dans les structures MOS plasmoniques / Compact and low energy consumption integrated optical modulator is urgently required for encoding information into optical signals. To that respect, the use of plasmon modes to modulate light is of particular interest when compared to the numerous references describing silicon based optical modulators. Indeed, the high field confinement properties of those modes and the increased sensitivity to small refractive index changes of the dielectric close to the metal can help decrease the characteristic length scales of the devices, towards to that of microelectronics.This thesis investigates the realization of Si field-effect plasmonic modulator integrated with a silicon-on insulator waveguide (SOI-WG) using the standard CMOS technology. The material aspects and also the technological steps required in order to realize an integrated plasmonic modulator compatible with requirements of CMOS technology were investigated. First, we demonstrate a Metal-Nitride-Oxide-Semiconductor (MNOS) stack for applications in electro-optical plasmonic devices, so that a very low optical losses and reliable operation is achieved. This objective is met thanks to a careful choice of materials: (i) copper as a metal for supporting the plasmonic mode and (ii) stoechiometric silicon nitride as an ultrathin low optical loss diffusion barrier to the copper. Final electrical reliability is above 95% for a 3 nm thick Si3N4 layer, leakage current density below 10-8 A.cm-2 and optical losses as low as 0.4 dB.μm-1 for a 13 nm thick insulator barrier, in agreement with the losses of the fundamental plasmonic mode estimated by 3D FDTD calculations, using the optical constant of Cu measured from ellipsometry. After demonstrating the MNOS as an appropriate structure for electro-optical CMOS plasmonics, we fabricate a vertical Metal-Insulator-Si-Metal (MISM) waveguide integrated with an SOI-WG, where the back metal was fabricated by flipping and molecular bonding of the original SOI wafer on a Si carrier wafer. The active device area varies from 0.5 to 3 μm2, 0.5 μm width and length varying from 1 to 6 μm.An efficient and simple way to couple light from Si-WG to vertical MISM PWG was experimentally realized by inserting a Metal-Insulator-Si-Insulator (MISI) coupling section between the two waveguides. We demonstrate that such couplers operates at 1.55 μm with the highest efficiency geometry corresponds to a compact length of 0.5 μm with coupling loss of just 2.5 dB (50 %) per facets. This value is 3 times smaller compared to the case of direct coupling (without any MISI section). High-k dielectrics are demonstrated as promising solution to reduce both the MISM absorption loss and the operation voltage. Given that interest, we experimental demonstrate an electrical reliable high-k stack for future applications to the MOS plasmonic modulators.A few μm long plasmonic modulator is experimentally investigated. Devices show leakage current below 10 fA through the copper electrodes based MOS capacitance. The accumulation capacitance (few fF) was found to scale with the surface of the device, in consistent with the expected equivalent oxide thickness of the MOS stack of our modulator. A low electro-absorption (EA) modulation showing capacitive behaviour was experimentally demonstrated in agreement with simulations. Finally, low energy consumption devices 6 fJ per bit was demonstrated.
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Filmes finos híbridos orgânicos-inorgânicos para fotônica /Oliveira, Daniela Coelho de. January 2006 (has links)
Resumo: O material estudado neste trabalho é um híbrido orgânico-inorgânico denominado "di-ureasil" formado por uma cadeia tipo poliéter unida em ambas extremidades a um grupo siloxano por pontes de uréia. As curvas de SAXS mostram um pico de interferência característico, atribuído a uma correlação espacial existente entre as partículas de siloxanos. Um complexo formado entre zircônio e ácido metacrílico foi adicionado ao material base e o aumento do teor deste complexo leva a um alargamento das bandas e um deslocamento de q para valores maiores. O alargamento é devido ao aumento na dispersão das distâncias interpartículas e o deslocamento pode ser devido a interação do zicônio com a região polimérica levando a uma diminuição das distâncias entre as partículas de siloxanos. As mesmas informações podem ser obtidas a partir das curvas de difração de raios X. A desconvolução gaussiana das curvas experimentais indica a formação de nanodomínios de óxido de zircônio. As curvas de transmissão na região do infravermelho mostram a interação dessas espécies de zircônio com a região polimérica da matriz híbrida. Entretanto, a competição pela água do meio reacional entre espécies de Zr e Si levam a uma diminuiçào no grau de condensação das espécies de siloxano evidenciada pelo aparecimento de bandas relativas a silanóis residuais apenas para amostras com alta concentração de zircônio. Este fato é confirmado pelas análises de RMN de 29Si. As propriedades ópticas dos di-ureasis também foram estudadas. Uma banda larga de emissão que cobre a parte do visível do espectro eletromagnético é devida à combinação de duas componentes atribuídas à processos de recombinação doador-aceptor, que ocorre entre grupos NH das ligações uréia e nos centros de siloxanos. / Abstract: The base material studied is the organic-inorganic host termed "di-ureasil" formed by poly(ether)-based chains grafted at both ends to a siloxone backbone through urea cross linkages. SAXS curves display a characteristic interference peak attributed to the spatial correlation between siloxane nanoparticles. A methacrylate modified zirconium alcoxide (Zr- AMA) was added to this base host and the increasing addition leads to broadening and q shift to higher values. Broadening is due to increasing dispersion in the interparticle distances and the shift could be due to zirconium interaction with the polymeric part leading decreasing distances between siloxane particles. Essentially the same information is obtained from XRD curves. Gaussian deconvolution of the experimental curves indicate the formation of zirconium oxide based nanodomains. FT-IR spectra analysis have shown the interaction of the zirconium based species with the polymeric part of the hybrid host. Moreover competition for water between Si and Zr species lead to decrease on the condensation degree of siloxane species as evidenced by the appearence of characteristic silanol bands only for higher Zr content. This fact is confirmed by 29Si NMR. The optical properties of the di-ureasils were also studied. A broad emission band covering the visible part of the electromagnetic spectrum is attributed to the convolution of two components assigned to radiative recombination processes typical of donor-acceptor pairs occurring in the NH groups of the urea cross-links and in the siliceous nanodomains. With the addition of Zr-AMA broadening is observed. Luminescence spectroscopy shows that the addition of highly emitting Eu3+ â -diketonate complex [Eu(tta)3(H2O)2] (where tta stands for thenoiltrifluoribetadiketonate) to the di-ureasil host has lead to interesting features. / Orientador: Sidney José Lima Ribeiro / Coorientador: Jean-Michel Nunzi / Banca: Luis Antonio Ferreira Martins Dias Carlos / Banca: Cid Bartolomeu de Araujo / Banca: Alain Fort / Doutor
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Projetos de camadas fotônicas 2D e fabricação utilizando múltiplas exposições holográficas / Design of 2D photonic layers and fabrication using multiple holographic exposuresMenezes, Jacson Weber de 28 July 2006 (has links)
Orientador: Lucia Helena Deliesposte Cescato / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-08T11:13:35Z (GMT). No. of bitstreams: 1
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Previous issue date: 2006 / Resumo: Nesta dissertação foi desenvolvido um novo método de gravação de estruturas bidimensionais em fotorresina, baseado na superposição de três exposições holográficas. Utilizando esta técnica, foi possível gravar estruturas de seção transversal circular. Isso resolve o problema da redução da área do gap fotonico que ocorre com as estruturas cilíndricas de seção transversal elíptica, obtida quando são utilizadas apenas duas exposições. Controlando-se a fase entre a terceira exposição e as duas anteriores é possível também gerar padrões hexagonais com diferentes formas de cilindros, que correspondem aos "átomos" do cristal fotonico, que podem apresentar novas propriedades fotonicas. Para projetar cristais fotonicos que apresentam gap fotonico na região de interesse do espectro eletromagnético, foi utilizado um programa baseado no método dos elementos finitos. Nestes projetos foram consideradas as dimensões e formas que podem ser fabricadas utilizando a técnica de dupla exposição holográfica assim como foi utilizada a aproximação de índice de refração equivalente para levar em conta a espessura da camada fotonica. Utilizando a superposição de duas exposições holográficas, associadas à litografia por corrosão por íon reativo, foram feitas tentativas de fabricação das camadas fotonicas projetadas em três materiais diferentes: silício policristalino, silício amorfo hidrogenado e silício cristalino / Abstract: In this work, it was developed a new recording method of the 2D structures in photoresist, based on the superimposition of three holographic expositions. This technique solves the problem of asymmetry of hexagonal structures, arising from the superimposition of only two expositions, which causes a strong reduction of the photonic band gap area. By controlling the phase-shift between the third exposition and the former two exposures, it is possible to generate new hexagonal patterns that can present different properties. In the design of the 2D photonic layers that present Photonic Band Gaps in the near infra-red region of the electromagnetic spectrum, it was used a software based on finite elements method. To consider the thickness of the photonic layer it was used the approach of equivalent refractive index. In the design we take into account the dimensions and shapes that can be fabricated using the technique of holographic lithography associated with RIE (Reactive Ion Etching). For fabrication of the structures we used double holographic exposures followed by RIE lithography in three different materials: poly-silicon, amorphous silicon and crystalline silicon / Mestrado / Física da Matéria Condensada / Mestre em Física
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[en] DEVELOPMENT AND CHARACTERIZATION OF PHOTONIC DEVICES / [pt] DESENVOLVIMENTO E CARACTERIZAÇÃO DE DISPOSITIVOS FOTÔNICOS UTILIZANDO POLÍMEROSLUCIENE DA SILVA DEMENICIS 17 August 2006 (has links)
[pt] Polimeros orgânicos de natureza conjugada têm despertado
bastante interessante como materiais ópticos não-lineares
por serem extremamente promissores para o desenvolvimento
de dispositivos fotônicos, como por exemplo dispositivos
de comunicações. Além de possuírem resposta óptica não -
linear intensa e rápida, seu modo de preparação e sua
forma final apresentam grande flexibilidade. Do ponto de
vista de aplicação, os parâmetros do material mais
importantes são : a susceptibilidade não-linear de
terceira ordem (x (3)) cuja parte real está relacionada
com o índice de refração não-linear e a parte imaginária
relacionada com o coeficiente de absorção não-linear; o
tempo de resposta; o coeficiente de absorção linear no
comprimento de onda de operação (alfa L); a capacidade de
processamento; o limiar de dano e a estabilidade térmica.
Dentre os polímeros conjugados, destaca-se a família dos
politiofenos, compostos heterocíclicos de elevada
estabilidade, que exibem interessantes propriedades de
transporte e acentuada não-linearidade de terceira ordem.
Neste trabalho as propriedades ópticas do politiofeno: X
(3), partes real e imaginária; alfaL; e tempo de resposta,
foram investigadas experimentalmente.
A técnica utilizada para medida dos efeitos não-lineares
de terceira ordem foi a técnica de Z-scan convencional. Os
valores absolutos e s sinais do índice de refração não -
linear e do coeficiente de absorção não-linear foram
encontrados como sendo da ordem de - 10 -12 cm 2/W e - 10 -
8 cm/W, respectivamente. Para analisar os resultados
experimentais foi necessário utilizar um tratamento
teórico relativamente novo. Esta abordagem teórica é
diferente da convencional e fornece resultados
satisfatórios que descrevem bem os resultados
experimentais. O tempo de resposta da não-linearidade do
politiofeno foi obtido com a técnica de Z-scan resolvida
no tempo, utilizando um único comprimento de onda e
polarizações cruzadas. O valor obtido foi inferior à 100
os.
Além de caracterizar o politiofeno, foi também demonstrada
a utilização dexte polímero comoporta lógica E (AND)m
através de uma medida envolvendo chaveamento Kerr. Este
experimento mostrou que é possível realizar um chaveamento
total óptico onde um feixe de luz é controlado por um
outro feixe de luz, com duração de algumas dezenas de
picossegundos. / [en] Conjugated organic polymers are of wide interest as
nonlinear optical materials because of their potential
applications in photonic devices, such as communication
devices. They have a large and fast nonlinear optical
response, as well as a great flexibility in their
preparing method. For device applications, the most
important parameters are: third-order optical nonlinear
susceptibility X(3), which real part is related with
nonlinear refractive index and imaginary part is related
with nonlinear absorption coefficient; response time;
absorptioon at operating wavelength alfaL; processability;
damage threshold; and thermal stability.
There are many conjugated polymers, and the polythiophene
class, which includes high stabilityn heterocyclic
compunds, is one of the most impoant because of its
interesting transport properties and large third-order
nonlinearity.
In this work the optical properties of polythiophene: X
(3), real and imaginary parts; alfaL and time response,
were investigated experimentally.
The Z-scan technique was used to measure the third-order
nonlinear effects. The value and the sign of the nonlinear
refractive index and nonlinear absorption coefficient of
the polythiophene were found to be around -10 -12cm2/W
and -10-8 cm/W, respectively. To analyze the experimental
data it wass necessary to use a new theoretical approach.
This approach is different from the conventional one and
produces better fitting of the experimental results. The
nonlinear response time of the polythiophene was measured
using the time-resolved Z-scan technique, using a single
waveguide and perpendicular polarizations. The time
response is smaller than 100 ps.
Besides the polythiophene characterization, it was
demonstrated that this polymer can work like an AND
logical gate using Kerr switching. This wxperiment showed
that it is possible to make a fast (picoseconds) all-
optical switch using a light beam to control another light
beam.
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Characterisation by X-ray diffraction of naturally occurring polycrystalline diamond samples from different originsMoipolai, Tshegofatso Bridgette 12 November 2015 (has links)
M.Phil. (Energy Studies) / Non-destructive investigations of unusual natural polycrystalline diamond samples are reported. The samples originate from various international locations discovered in soils and sediments and may have been formed by di erent mechanisms which are the subject of debate. Analysis techniques include scanning electron microscopy, with energy dispersive spectroscopy and X-ray di raction. Sample composition, structure and surface stresses were investigated. The samples (two Egyptian nodules, two Brazillian carbonados, two Venetian ballas diamonds and a polycrystalline diamond compact sample consisting of a polycrystalline diamond layer sintered onto a Co-cemented tungsten carbide support) are cubic diamonds, with varying amounts of minority phases. In most cases the minority phases could not be identi ed unambiguously due to their low intensities and the overlap of Bragg peaks. The Egyptian nodule samples in particular showed a large presence of oxygen that could not be linked to speci c metal oxides. The Ballas samples had the lowest impurity content. Using a Rietveld based quanti cation analysis, the crystalline cubic diamond contents were determined respectively as 99 wt.%, 98 wt.% and 76 wt.% in the Ballas, Brazilian carbonado and Egyptian nodule samples. A signi cant result from this study is the substantial inhomogeneous peak broadening observed in the X-ray diffraction patterns of the Egyptian samples. This is indicative of the presence of nano-crystalline diamond grains in addition to substantial mechanical deformation with extensive accumulation of dislocations and crystalline defects. These observations are supportive of a recently proposed impact mechanism for their formation.
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Croissance auto-catalysée de nanofils d'InP sur silicium par épitaxie par jets moléculaires en mode vapeur-liquide-solide : application aux interconnexions optiques sur puceBarakat, Jean-Baptiste 22 October 2015 (has links)
L’intégration monolithique de matériaux semi-conducteurs III-V sur substrat de Silicium est essentielle pour le développement de la photonique sur Silicium. L’objectif est de réaliser une micro-source optique à base d’un réseau ordonné de Nanofils (NFs) III-V (InAsP/InP) placés sur un guide d’onde Si. De par leur aptitude à relaxer les contraintes, les NFs sont d’un grand intérêt. C’est dans ce contexte que s’est déroulée cette thèse axée sur la croissance autocatalysée de NFs InP sur Silicium par épitaxie directe. Nous avons ainsi montré que la croissance auto-catalysée de NFs InP denses et verticaux dépend directement de la nature de l’oxyde de surface du substrat Si. Une distribution monomodale ou bimodale de NFs ont été achevées en fonction des conditions de formation des gouttelettes d’indium ou des paramètres de croissance. Une pression critique et une température critique ont permis de délimiter des domaines favorables à la croissance. Les propriétés optiques intrinsèques des NFs ont été déterminées suffisantes pour l’objectif visé. Enfin, des résultats sur la simulation optique et la polarisation de la lumière émise dans les NFs et le guide d’onde ont permis d’établir un cahier des charges pour la croissance des NFs verticaux sur SOI pour que le couplage/partage de leurs modes optiques soit le plus efficace possible aux longueurs d’onde télécom. / Monolithic integration of III-V semiconductors materials on Si substrate is essential for the Si photonic development. We aim at achieving an optical microsource based on a regular array of III-V (InAsP/InP) nanowires (NWs) standing on top a Si waveguide. Due to their ability to be fully relaxed, nanowires growth is of deep interest. This PhD thesis has been oriented towards such context especially among self-catalyzed InP NWs growth by epitaxy. Thus we have shown that highly dense and vertical self-catalyzed InP NWs accomplishment is related to Si substrate surface oxide. A monomodal or bimodal NWs distribution have been reached through a control of indium droplets formation or growth parameters. A critical pressure and a critical temperature have been found to delimit favorable growth regime. Intrinsic optical properties have been determined to be goal sufficient. Optical simulation modeling and characterization of the polarization light state in NWs and in the Si waveguide have led us to establish functional specifications to grow vertical NWs on SOI as way that their optical modes could be coupled efficiently at telecommunications wavelength.
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Multifunctional Organic-Inorganic Hybrid Nanophotonic DevicesGarner, Brett William 05 1900 (has links)
The emergence of optical applications, such as lasers, fiber optics, and semiconductor based sources and detectors, has created a drive for smaller and more specialized devices. Nanophotonics is an emerging field of study that encompasses the disciplines of physics, engineering, chemistry, biology, applied sciences and biomedical technology. In particular, nanophotonics explores optical processes on a nanoscale. This dissertation presents nanophotonic applications that incorporate various forms of the organic polymer N-isopropylacrylamide (NIPA) with inorganic semiconductors. This includes the material characterization of NIPA, with such techniques as ellipsometry and dynamic light scattering. Two devices were constructed incorporating the NIPA hydrogel with semiconductors. The first device comprises a PNIPAM-CdTe hybrid material. The PNIPAM is a means for the control of distances between CdTe quantum dots encapsulated within the hydrogel. Controlling the distance between the quantum dots allows for the control of resonant energy transfer between neighboring quantum dots. Whereby, providing a means for controlling the temperature dependent red-shifts in photoluminescent peaks and FWHM. Further, enhancement of photoluminescent due to increased scattering in the medium is shown as a function of temperature. The second device incorporates NIPA into a 2D photonic crystal patterned on GaAs. The refractive index change of the NIPA hydrogel as it undergoes its phase change creates a controllable mechanism for adjusting the transmittance of light frequencies through a linear defect in a photonic crystal. The NIPA infiltrated photonic crystal shows greater shifts in the bandwidth per ºC than any liquid crystal methods. This dissertation demonstrates the versatile uses of hydrogel, as a means of control in nanophotonic devices, and will likely lead to development of other hybrid applications. The development of smaller light based applications will facilitate the need to augment the devices with control mechanism and will play an increasing important role in the future.
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