Skapandet av en goboarmatur för hemmiljö med en energieffektiv ljuskälla som LED.

To cope with the global trend of energy conservation, LED lighting industry has become a new generation of the mainstream market. With the features of low energy consumption and pretty looks, LED lighting will replace the traditional lighting market. According to the institute study, it is estimated that the global lighting market will grow to 94 billion U.S. dollars by 2010. In order to identify the key elements of Taiwan's Lighting industry development, Michael Porter's five forces Model and SWOT analysis has been adopted in this paper. A domestic LED lighting manufacturer-D Co, Ltd. was interviewed as a case study in this paper. The results indicated that the advantage of Taiwan¡¦s lighting industry development advantage lies in the well industrial chain integrity, professional and technical research and development staff. On the other hand, the disadvantage is that LED lighting products are priced too high. If the production can not achieve economies of scale, it is difficult to promote products. The paper proposes from both marketing and production operations to improve in marketing. To formulate business strategy and understand the market needs of customers and how to achieve customized marketing for D Company is the urgent need to address. For the aspect of production, the performance measurement systems must be established to strengthen research and development and technical staff production performance. In addition, it must have a sound accounting system and management information system to enable the overall operation of D Company and to improve the allocation of production resources for maximum effectiveness.

Le domaine des écrans est en pleine mutation. De nouvelles technologies d’écrans (principalement LCD et OLED) ont remplacé l’écran à tube cathodique du XXème siècle et ouvrent la voie vers de nouvelles fonctionnalités (écran 3D, flexible, transparent). Depuis quelques années, un genre particulier d’écran fait l’objet de nombreuses recherches, notamment pour adresser de nouveaux marchés tels que la réalité augmentée : les micro-écrans. Pour cela, les contraintes technologiques sont fortes. L’écran doit être miniature (quelques millimètres de diagonale) tout en permettant une qualité d’image semblable aux écrans traditionnels. Il doit aussi être compact, économe en énergie et très lumineux. Une nouvelle technologie d’écran est à l’étude depuis quelques années et doit permettre d’atteindre ses spécifications. Il s’agit des micro-écrans LED, constitués d’un réseau de LED micrométriques, dans lequel chaque diode constitue un pixel de l’image. L’objectif de cette thèse est d’étudier les spécificités des matrices de LED en nitrure de gallium (GaN) en vue de leur utilisation dans des micro-écrans.Les recherches menées au cours de cette thèse portent sur trois axes d’étude. Le premier concerne l’optimisation du rendement à travers l’étude du procédé de matriçage d’une épitaxie LED. L’amélioration de la métallisation P et de l’intégrité électrique du P-GaN a permis d’augmenter le rendement d’un facteur 10 sur les micro-LED. Le deuxième axe de travail concerne l’étude des effets de taille. La réduction de la taille des LED entraine une forte baisse du rendement maximum. Les études menées ont permis l’attribuer principalement à des recombinaisons non-radiatives sur les bords de pixel. Le troisième axe de recherche porte sur l’étude des micro-LED en tant que réseau bidimensionnel permettant la formation d’images. Les principales sources d’inhomogénéité et de dispersion ont été étudiées. Des solutions ont été proposées pour éliminer le cross-talk optique et améliorer l’extraction lumineuse, principal frein au rendement de nos micro-LED. Enfin, des micro-écrans LED fonctionnels, bleus et verts, à l’état de l’art mondial ont été obtenus et caractérisés au cours de cette thèse / The display industry is facing a fast transformation. New technologies (mainly LCD and OLED) have faded-out the cathode ray tube of the 20th century and lead to new applications (3D, flexible and transparent displays). A very particular type of display has recently emerged to address new markets, such as augmented reality: micro-displays. They can be defined as having a diagonal of around 1 inch or less. One important goal of these micro-displays is to deliver the same image quality as conventional, larger-size displays. Strong challenges arise in terms of definition, compactness, consumption and brightness. To address these, LED micro-displays are currently being studied. In a LED micro-display, a 2D-array of micro-LEDs is fabricated, where each LED acts as a single pixel of a whole image. The main objective of this thesis work is to study the specifics of Gallium Nitride (GaN) micro-LEDs arrays for micro-display applications.Our investigations have been carried out focusing on three major areas of study. Increasing LED efficiency through the study of our fabrication process was the first goal. By improving P metal and enhancing P-GaN electrical performances, we were able to increase efficiency of micro-LED by a factor of 10.The influence of size-reduction on the performances of LEDs have then been thoroughly investigated. As LED size decreases, its maximum efficiency drops. Non-radiative recombinations occurring at the edges of the LED were found to be the main origin. We have then studied LEDs, not as a single diode, but as a dense 2D array of micro-LEDs allowing image display, and optical and electrical spread have been investigated. Furthermore, optical cross-talk has been studied and fabrication was changed to address this issue. New structures have also been suggested to improve light extraction efficiency, which is one of the main hindrance towards high-efficiency micro-LEDs. Finally, state-of-the-art, blue and green, active matrix micro-LED displays have been obtained and characterized during the course of this thesis work.

abstract: A novel integrated constant current LED driver design on a single chip is developed in this dissertation. The entire design consists of two sections. The first section is a DC-DC switching regulator (boost regulator) as the frontend power supply; the second section is the constant current LED driver system. In the first section, a pulse width modulated (PWM) peak current mode boost regulator is utilized. The overall boost regulator system and its related sub-cells are explained. Among them, an original error amplifier design, a current sensing circuit and slope compensation circuit are presented. In the second section – the focus of this dissertation – a highly accurate constant current LED driver system design is unveiled. The detailed description of this highly accurate LED driver system and its related sub-cells are presented. A hybrid PWM and linear current modulation scheme to adjust the LED driver output currents is explained. The novel design ideas to improve the LED current accuracy and channel-to-channel output current mismatch are also explained in detail. These ideas include a novel LED driver system architecture utilizing 1) a dynamic current mirror structure and 2) a closed loop structure to keep the feedback loop of the LED driver active all the time during both PWM on-duty and PWM off-duty periods. Inside the LED driver structure, the driving amplifier with a novel slew rate enhancement circuit to dramatically accelerate its response time is also presented. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2016

Dentre os vários compostos utilizados na pesquisa e na terapia de doenças osteo-degenerativas, a fototerapia com laseres de baixa potência (LLLT) e os diodos emissores de luz (LEDs) vem sendo investigada com o intuito de avaliar seus efeitos no metabolismo ósseo. Estes, que possuem comprimentos de ondas específicos, atuam na biomodulação das células, funcionando como um agente terapêutico, reequilibrando e normalizando a sua atividade. No entanto, pouco se sabe sobre o efeito dos diferentes espectros na proliferação e diferenciação de osteoblastos humanos, bem como seus efeitos no metabolismo celular como a síntese e a ativação de proteínas sinalizadoras envolvidas nesses processos. Diante disso, o objetivo deste trabalho foi avaliar, comparativamente, a influência da fototerapia com LLLT e LED na proliferação e diferenciação de osteoblastos humanos. Além disso, investigamos o envolvimento da ativação da via de sinalização ERK1,2 nestas respostas, utilizando o seu inibidor específico e/ou avaliando a sua ativação durante a proliferação e após fototerapia. Para esse estudo, osteoblastos humanos (HOAL) foram cultivados em meio de cultura DMEM suplementado com 10% de soro fetal bovino (SFB) e incubados em estufa de CO2. As células foram irradiadas pontualmente com os laseres vermelho (660nm), infravermelho (780nm) e LED (637nm), nas doses de 10, 20 e 50 J/cm2 na potência de 40mW, após adesão celular. Após 24, 48, e 72 horas foram realizados os ensaios de redução do MTT (brometo de 3-(4,5-dimetiltiazol-2-yl)-2,5- difeniltetrazólio) e cristal violeta (CV) para avaliar a viabilidade das células e após 72 horas foi realizada a análise da proliferação por citometria de fluxo nos quais os resultados sugerem aumento de células viáveis ou proliferação quando estimuladas pelos diferentes espectros. Após a verificação do efeito positivo dos laseres e LED na viabilidade e/ou proliferação, foi realizada a análise da ativação da proteína intracelular ERK por western blotting usando anticorpo específico após 10 minutos da irradiação pontual. Mostramos que a irradiação das células HOAL com LLLT, na dose de 10 J/cm2, aumentou significativamente a fosforilação da ERK1/2 em relação ao controle. Para os ensaios de diferenciação, as células receberam pontualmente o estimulo a cada 6 dias e após os períodos de 07, 14, 21 e 28 dias foram realizados os ensaios da atividade de fosfatase alcalina (ALP), expressão gênica do colágeno I (COL1A1) e SPARC (osteonectina) por RT-PCR em tempo real e ensaio de mineralização com vermelho de alizarina. De um modo geral, não foram observados diferenças na atividade da ALP entre os grupos tratados em relação ao controle. A expressão gênica do COL1A1 e SPARC foi aumentada, no qual o LED em ambas doses apresentou maior eficácia em aumentar a expressão desses genes. No que se refere à mineralização, foram observadas pequenas diferenças quanto a deposição de cálcio. Dessa forma, a LLLT e LED, nesse regime de aplicação modulou positivamente o metabolismo dos osteoblastos humanos em relação à viabilidade, porém, no processo de mineralização foram observadas poucas diferenças. / Among the various compounds used in research and bone degenerative diseases therapy, phototherapy with low level laser (LLLT) and light emitting diodes (LEDs) has been investigated in order to evaluate its effects on bone metabolism. Those, who have specific wavelengths, act in biomodulation cells functioning as a therapeutic agent, rebalancing and normalizing their activity. However, little is known about the effect of the different spectra in the proliferation and differentiation of human osteoblasts and their effects on cellular metabolism as well as the synthesis and activation of signaling proteins involved in these processes. Therefore, the aim of this study was to compare the influence of LLLT and LED phototherapy in the proliferation and differentiation of human osteoblasts. In addition, we investigated the involvement of activation of ERK1,2 signaling pathway these responses using its specific inhibitor and/or evaluating their activation during the proliferation and after phototherapy. For this study, human osteoblasts (HOAL) were cultured in DMEM culture medium supplemented with 10 % fetal bovine serum (FBS) and incubated in CO2 incubator . Cells were irradiated with punctual red lasers (660nm), infrared (780nm) and LED (637nm) at doses of 10, 20 and 50 J/cm2 in power 40mW, after cell adhesion. After 24, 48, and 72 hours, MTT assay (- (4,5- dimethylthiazol-2- yl) -2,5 - diphenyltetrazolium bromide 3 ) and violet crystal (CV) were performed to assess the viability of cells and after 72 hours, was performed of proliferation analysis by flow cytometry. The results suggest an increase in viable and proliferation of cells when stimulated by different spectra. After checking the positive effect of lasers and LED viability and/or proliferation, analysis of ERK activation of intracellular protein by western blotting using a specific antibody was performed 10 minutes after the spot irradiation. We show that irradiation of HOAL cells with LLLT at a dose of 10 J/cm2, significantly increased the phosphorylation of ERK1/2 compared to control. For differentiation assays, cells promptly received stimulation every 6 days and after periods of 07, 14, 21 and 28 days testing the activity of alkaline phosphatase (ALP), gene expression of type I collagen (COL1A1) and SPARC (osteonectin) were performed by Real Time RT-PCR and mineralization experiment with alizarine red. In general, no differences in the activity of ALP between the treated groups compared to the control were observed. The gene expression was increased, and SPARC COL1A1, where in the LED in both doses showed greater effectiveness in increasing the expression of these genes. With respect to mineralization, small differences in the deposition of calcium were observed. Thus, LLLT and LED, this enforcement regime, positively modulated the metabolism of human osteoblasts during the cell viability, but in the process of mineralization few differences were observed.

Em uma viagem de avião os passageiros ficam de 1 a 12 horas em determinada localização, na maior parte do tempo sentados, com limitações nos ajustes de seus assentos, expostos a ruídos, vibrações mecânicas, temperaturas desconfortáveis, condições que podem levá-los a um processo de estresse em função do desconforto a que estão sujeitos. Outro fator importante para a sensação de desconforto é a qualidade e a cor da iluminação do interior da aeronave. A cor de uma iluminação tem influência no estado de humor das pessoas, que pode afetar de maneira positiva ou negativa o seu estado emocional. Com o avanço tecnológico e a invenção LED (Light Emitting Diode, Diodo Emissor de Luz) pode-se criar uma iluminação no interior da cabine, com cores que podem ser alteradas facilmente e dessa maneira influenciar o estado emocional dos passageiros. O objetivo da presente pesquisa é determinar a sensação de conforto/desconforto causada pela cor da iluminação em uma cabine de aeronave. Foi realizada uma pesquisa bibliográfica para se obter dados sobre a influência das cores no estado emocional das pessoas. Também foi pesquisado o mecanismo de funcionamento do sistema visual humano e como percebemos as informações visuais. A pesquisa foi realizada com uma população representativa de passageiros de aeronaves. Fez-se um levantamento quantitativo de aspectos subjetivos da percepção da qualidade do ambiente em função da cor da iluminação, por meio da aplicação da técnica do diferencial semântico. O ambiente de estudo desta investigação foi um mockup que reproduz o interior de uma cabine de aeronave em condições semelhantes a uma viagem de avião. Avaliou-se a influência de algumas características físicas dos passageiros, tais como gênero, cor dos olhos e Índice de Massa Corporal (IMC), na percepção da qualidade do ambiente em função da cor da iluminação. Os resultados das análises mostraram que as sensações percebidas do ambiente são afetadas pelas características físicas dos indivíduos, com diferenças significativas de percepção da qualidade do ambiente entre o sexo masculino e o feminino, entre IMC>25 e IMC<25, e entre olhos claros e olhos escuros. Pela análise dos resultados também se determinou cores mais adequadas para reduzir o estresse de uma viagem de avião e para cada fase do voo. O resultado encontrado apresentou um grau de incerteza elevado, com desvio padrão de 20 pontos em uma amplitude de valores de 0 a 100, o que evidencia a subjetividade das percepções. Este resultado revela que o ideal, em termos de conforto da cor da iluminação, é individualizar a iluminação. Além das possibilidades práticas de aplicação em cabines de aeronave, o resultado obtido poderá se estender a outras aplicações, em que se busca o bem estar propiciado por uma cor de iluminação adequada. / On a plane trip passengers could stay from 1 to 12 hours in a specific location, most of the time sitting with limitations related to the settings of their seats, subjected to noise, vibration, uncomfortable temperatures, conditions that can lead them to a stress due to the discomfort process that they are exposed. Another important factor for the discomfort factor is the quality and color of aircraft interior illumination. The color of illumination influences the people´s mood, which can positively or negatively affect their emotional state. With technological advancement and invention of LED (Light Emitting Diode) it is possible to create a lighting inside the cabin with colors that can be changed easily and thus influence the passengers´ emotional state. The aim of this research is to determine the sense of comfort / discomfort caused by the lighting color in an aircraft cabin. A literature survey was conducted to obtain data about the influence of colors on people´s emotional state. It was also investigated the mechanism of functioning of the human visual system and how we perceive visual information. The survey was conducted with a representative sample of passenger aircraft. It was made a data collection about subjective aspects of the environment perception due to the illumination color by applying the technique of semantic differential. The study environment of this research was a mockup that reproduced the interior of an aircraft cabin in conditions similar to a plane trip. It was assessed the influence of some physical passengers characteristics, such as gender, eyes color and body mass index (BMI), in the perception of the environment due to the illumination color. The analysis of the results showed that the perceived sensations of the environment are affected by the physical characteristics of the persons, and that there were significant differences in perception of the environment between male and female, between BMI > 25 and BMI < 25, and between light eyes and dark eyes. Through the analysis of the results it was also determined most appropriate colors to reduce the stress of traveling by plane and for each phase of flight. The results founded showed a high degree of uncertainty, with a standard deviation of 20 points in a range of values from 0 to 100, which demonstrates the subjectivity of perceptions. This result reveals that the ideal, in terms of comfort Illumination color, is to individualize the lighting. Apart from the practical possibilities of application in aircraft cabins, the result can be extended to other applications where one seeks the well being brought by a color proper lighting is seek.

O objetivo neste estudo foi avaliar a velocidade de movimentação dentária no fechamento dos espaços durante a fase de retração em pacientes ortodônticos, submetidos a tratamento com extração dos primeiros pré-molares. Foram selecionados 18 pacientes sendo 9 homens e 9 mulheres, com idades entre 13 e 18 anos, alocados sequencialmente em dois grupos: LED (GLED) composto por dez pacientes (5 H, 5 M) que fizeram auto aplicação com aparelho de LED, durante 10 minutos diários, durante a fase de retração ortodôntica, por um período de 12 semanas e Controle (GC), composto por oito pacientes (4 H, 4 M) que não aplicaram o LED durante a mesma fase. O fechamento dos espaços das extrações foi obtido com mecânica de deslize com arcos de aço com calibre 0.019\" x 0.025\" e molas de níquel-titânio com 200g de força, ativadas a cada 4 semanas. A mecânica escolhida permitiu-nos analizar 36 quadrantes e não 18 pacientes e isto justifica o tamanho final da nossa amostra: GLED 20 quadrantes superiores e 16 quadrantes inferiores e GC 16 quadrantes superiores e 12 quadrantes inferiores. Na arcada superior a retração foi ancorada em mini-implantes ortodônticos, e na arcada inferior sem acessórios de ancoragem e por este motivo foram avaliadas separadamente. Para avaliar o fechamento dos espaços, após calibragem, um único operador realizou dois tipos de medições: clínicas e em modelos de estudo, com compasso de ponta seca e paquímetro digital modificado, considerando quatro variáveis consistentes em distância entre os dois dentes vizinhos ao espaço da extração. Os resultados mostraram quedo início (T0) ao término do período de observação (T3) não houve diferença estatísticamente significante entre os grupos, exceto na medição dos modelos da arcada inferior, nas variáveis 1,3 e 4, com maior redução dos espaços no GLED: GLED > GC. Observou-se também diferença significante entre os grupos apenas na variável 1 do GLED na medição dos modelos da arcada inferior, no sentido de maior velocidade entre T1 e T2. Não houve diferença estatística entre os tipos de medidas realizadas clinicamente e nos modelos de estudo. Independentemente da aplicção ou não do LED obdservou-se uma significativa redução dos espaços ao longo do tempo em ambos os grupos, tanto da arcada superior, como na arcada inferior, que permitiu o sucesso do tratamento ortodôntico. Com base nos resultados pôde-se concluir que o protocolo de aplicação do LED utilizado na casuística estudada não caracterizou diferencialmente os grupos estudados. Porém, por ser um método novo na avaliação da influência sobre a movimentação dentária, sem dados na literatura para comparar os nossos, faz-se necessário a realização de estudos futuros que testem protocolos de mecânica ortodôntica e aplicação de LED. / The aim of this study was to evaluate the speed of tooth movement in space closure during the retraction stage, in orthodontic patients submitted to treatment with first premolar extractions. Eighteen (18) patients undergoing orthodontic treatment were selected, of whom 9 were men, and 9 women, age-range between 13 and 18 years, sequentially allocated to two groups. LED (GLED) composed of ten patients (5 M, 5 W) who performed self-application with a LED appliance, for 10 minutes daily, during the stage of orthodontic retraction, for a period of 12 weeks, and the Control Group (GC), composed of eight patients (4 M, 4 W) who did not apply LED during the same stage. Space closure of the extractions was obtained with sliding mechanics with steel archwires, caliber 0.019\" x 0.025\" and nickel-titanium springs with 200 g of force, activated every 4 weeks The mechanics chosen allowed the authors to analyze 36 quadrants and not 18 patients, and this justified the final size of our sample: GLED 20 maxillary quadrants and 16 mandibular quadrants; and GC 16 maxillary quadrants and 12 mandibular quadrants. In the maxillary arch, retraction was anchored on orthodontic mini-implants and in the mandibular arch, no anchorage accessories were used; and for this reason, they were evaluated separately. To evaluate space closure, after calibration a single operator performed two types of measurements: clinical, and in study models, by using a dry tip compass and modified digital pachymeter, considering four variables of distances between the two neighboring teeth, compatible with the extraction space. The results showed that from the beginning (T0) up to conclusion of the observation period (T3) there was no statistically significant difference between the groups, except for the measurements of the mandibular arch models, in the variables 1,3 and 4, showing greater reduction of the spaces in GLED: GLED > GC. The authors also observed significant difference between the groups only in variable 1 of GLED, in the measurements of the mandibular arch models, showing greater velocity between T1 and T2. There was no statistical difference between the types of measurements performed clinically and those in the study models. Irrespective of the application, or no application of LED, a significant reduction was observed in the spaces over time in both groups, both in the maxillary and mandibular arches, which allowed the orthodontic treatment to be successful. Based on the results, the authors could conclude that the LED application protocol used in the casuistic studied did not characterize the groups studied in a differential manner. However, since this was a new method for evaluating the influence on tooth movement, without data in the literature to compare with those of the authors, it is necessary to conduct future studies that test the orthodontic mechanics and LED application protocols.

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2015-07-21T15:07:51Z No. of bitstreams: 1 Ana Maria de Souza.pdf: 717565 bytes, checksum: 0b6ad0f4adba71695d0147808fdc405c (MD5) / Made available in DSpace on 2015-07-21T15:07:51Z (GMT). No. of bitstreams: 1 Ana Maria de Souza.pdf: 717565 bytes, checksum: 0b6ad0f4adba71695d0147808fdc405c (MD5) Previous issue date: 2013-12-10 / The aim of the present study was to evaluate the influence of different doses of energy and uni- or multi-wave LED units on mechanical properties of composite resins. Thereunto, six experimental groups were established for each assessed resin (IPS Empress Direct - Ivoclar Vivadent , Venus - Heraeus - Kulzer , SDR - Dentsply) according to the different different amounts of energy (5J , 10J and 20J) and LED unit (bluephase 16i and bluephase G2 - Ivoclar Vivadent) . Thirty six specimens were prepared (7mm long x 2mm wide x 1mm height) from silicon matrices and were used for evaluation of mechanical properties (flexural strength and modulus of elasticity) using the three points bending test, in a universal testing machine at a speed of 0.5 mm/min until the specimens fracture. Data were tested for normality and then the two-way analysis of variance was applied and Tukey's test was used to point out differences among means, with significance level set at 5%. Thus, the results showed that the resins presented different performance by energy amounts and by the difference of the spectra of light emitted by different sources. It appears from the data presented that the factors studied in this work are directly related to the mechanical properties of resin composites. / O objetivo do presente estudo foi avaliar a influência de diferentes doses de energia e unidades LED fotoativadoras de banda estreita e com amplo espectro nas propriedades mecânicas de resinas compostas. Para isso, 6 grupos experimentais foram estabelecidos para cada resina avaliada (IPS Empress Direct – Ivoclar Vivadent, Venus – Heraeus-Kulzer, SDR - Dentsply), de acordo com as diferentes doses de energia (5J; 10J e 20J) e unidades fotoativadoras (Bluephase 16i e Bluephase G2 – Ivoclar Vivadent). Trinta e seis corpos-de-prova foram confeccionados (7mm comprimento X 2mm largura X 1mm de altura) a partir de matrizes de silicone e foram utilizados para avaliação das propriedades mecânicas (resistência à flexão e módulo de elasticidade) utilizando o teste de flexão de três pontos, em máquina de ensaio universal a uma velocidade de 0,5 mm/min até que ocorresse a fratura do corpo-de-prova. Os dados foram avaliados quanto à sua normalidade e então, aplicado a Análise de Variância a dois critérios e teste de Tukey, com nível de significância fixado em 5%. Os resultados mostraram que as resinas apresentaram comportamentos diferentes entre si tanto pelas doses de energia utilizadas quanto pela diferença dos espectros de luz emitidos pelas diferentes fontes. Conclui-se dos dados apresentados que os fatores estudados neste trabalho têm relação direta com as propriedades mecânicas dos compósitos resinosos.

The main topics of the thesis are luminaries based on LED technology and methods for driving them. The aim of theoretical part is to offer basic knowledge about LEDs, their categories, advantages and disadvantages. The basic methods for driving LED modules are also presented. Based on these facts the design of LED switching power supply for street lighting is presented. The aim is to reach high power factor. The function of the devices is presented by examining parts of the power supply.

Les nanofils nitrures présentent des propriétés optoélectroniques extraordinaires et sont considérés comme des matériaux prometteurs pour des diodes électroluminescentes (LEDs), grâce à leur haute qualité cristalline, leurs surfaces non-polaires, leur bonne flexibilité mécanique, leur rapport d’aspect élevé, etc.Cette thèse adresse la croissance, la fabrication, les caractérisations optiques et électriques et la simulation optique des dispositifs à base de nanofils nitrures, avec un accent particulier sur les LEDs à nanofils.Premièrement, cette thèse présente la croissance par épitaxie en phase vapeur aux organométalliques de nanofils nitrures cœur-coquille auto-assemblés contenant des puits quantiques InGaN/GaN sur les facettes plan m avec différentes concentrations d’In. Puis est décrite la fabrication de LEDs utilisant ces nanofils suivant deux différentes stratégies d’intégration (intégrations planaires et verticales).L’intégration planaire est basée sur des nanofils uniques dispersés horizontalement. J’ai proposé une plateforme photonique intégrée composée d’une LED à nanofil, d’un guide d’onde optimisé et d’un photodétecteur à nanofil. J’ai également développé un système d’alignement des nanofils.L’intégration verticale a pour objectif la réalisation de LEDs flexibles reposant sur une assemblée de nanofils verticaux encapsulées dans des polymères. Je montre que ceci permet la fabrication de LEDs flexibles monochromatiques, bi-couleurs ou blanches.Les nanofils épitaxiés sur des matériaux 2D par épitaxie de van de Waals sont faciles à décoller de leur substrat natif. Avec cette motivation, dans la dernière partie de cette thèse, j’ai étudié la croissance organisée des nanofils GaN sur du graphène micro et nano-structuré utilisant l’épitaxie par jets moléculaires. / Nitride nanowires exhibit outstanding opto-electronic and mechanical properties and are considered as promising materials for light-emitting diodes (LEDs), thanks to their high crystalline quality, non-polar facets, good mechanical flexibility, high aspect ratio, etc.This Ph.D. thesis addresses the growth, the device fabrication, the optical and electrical characterizations and the optical simulations of III-nitride NW devices, with a special emphasis on the LED applications.First, this thesis presents the growth of m-plane InGaN/GaN quantum wells with different In concentrations in self-assembled core-shell nanowires by metal-organic chemical vapor deposition. Then, by using these nanowires, LED devices based on two different integration strategies (namely, in-plane and vertical integration) are demonstrated.The in-plane integration is based on the horizontally dispersed single nanowires. I have proposed a basic integrated photonic platform consisting of a nanowire LED, an optimized waveguide and a nanowire photodetector. I have also developed a nanowire alignment system using dielectrophoresis.The vertical integration targets the fabrication of flexible LEDs based on vertical nanowire arrays embedded in polymer membranes. Flexible monochromatic, bi-color, white LEDs have been demonstrated. Their thermal properties have been analyzed.The nanowires grown on 2D materials by van der Waals epitaxy are easy to be lifted-off from their native substrate, which should facilitate the fabrication of flexible nanowire devices. With this motivation, in the last part of this thesis, I have investigated the selective area growth of GaN NWs on micro- and nano- scale graphene by molecular beam epitaxy.