Tesis sobre el tema "Er luminescence"
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Chen, Thomas D. (Thomas Duhwa). "Energy transfer and luminescence enhancement in Er-doped silicon". Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9536.
Texto completoAlso issued in pages.
Includes bibliographical references (leaves 143-152).
Er-doped silicon (Si:Er) is a promising light emitting material for silicon microphotonics. A study of Si:Er excitation/de-excitation mechanisms and luminescence enchancement is presented in this thesis. A model based on impurity Auger and nonradiative nmltiphonon transitions (NRl\·IPT) is shown to describe the temperature quenching of the photoluminescence (PL) intensity from 4K to 300K This model asserts that the nonradiative Auger process is mainly responsible for the temperature quenching below lOOK, and NRMPT backtransfer process is mainly responsible for the temperature quenching above lOOK. Junction photocufrei1t · spectmscopy (JPCS) measurements confirmed the existence of a backtransfer mechanism that grows with temperature in accordance to the model. In order to circumvent the onset of nonradiative transitions at higher temperatures, spontaneous emission enhancement in nrnltilayer Si/Si02 microcavities was explored as a means to increase the PL intensity. Because multilayer microcavity structures cannot be constructed using single crystal silicon, Er-doped polysilicon (poly-Si:Er) was developed as a light emitting material for these microcavities. The poly-Si:Er material exhibited a luminescence very similar to that of Er in single crystal silicon. By crystallizing poly-Si:Er from amorphous material and performing a post-anneal hydrogenation, a reasonably high PL intensity, which was limited by the excitation power, was attained. Microacavities with poly-Si:Er were fabricated and measured for the first time. Cavity quality factors of -60-300 were measured, and an Er enhancement of -20x was observed. A -lOx enhancement of a small background emission from the polysilicon was also observed. The observed enhancement factors match well with computed enhancement factors derived from electric field intensity distribution within the microcavity structure. Exploratory work in optical gain from Si:Er waveguides and vertically coupled ring resonntors was conducted. A fiber coupling technique for low temperature waveguide transmission experiments was developed for the gain experiments. The transmission spectrum of a 3-cm long waveguide was measured at temperatures down to 125K. Because the temperature could not be lowered without debonding the fiber, a net gain could not be observed in this particular waveguide. The application of stimulated emission in Si:Er devices is analyzed and discussed.
by Thomas Duhwa Chen.
Ph.D.
ROGARD, STEPHANIE. "Contribution a l'etude de verres fluores dopes a l'erbium : dosage de er#3#+ dans des fibres optiques actives en zblan, mise en evidence de contraintes dans des pzg : er#3#+ evapores". Le Mans, 1997. http://www.theses.fr/1997LEMA1010.
Texto completoChen, Kevin M. (Kevin Ming) 1974. "Electrical breakdown and luminescence from erbium oxide and Er-doped silicon thin films". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9816.
Texto completoHussain, Syed Sajjad. "Elaboration, caractérisation structurale et luminescence de dépots AIN dopés Er obenus par PVD magnétron RF". Thesis, Nancy 1, 2010. http://www.theses.fr/2010NAN10060/document.
Texto completoThe work presented here is a contribution to the study of the photoluminescence (PL) properties of a rare earth ions (Erbium) inserted inside wide gap matrices (AlN) of different morphologies and deposited as thin films. A physical vapour deposition magnetron rf technique has been used to obtain thin layers of aluminium nitride whose crystalline morphologies are ranging from the classical columnar morphology to the nanocrystalline state or amorphous. One shows how, the higher the magnetron power, the larger are the columnar crystallites and how the use of a negative polarization on the silicon substrates allows obtaining nano crystallized layers. Different doping rates (from 0.1 to 6 at. %) have been achieved using a Al+Er composite target.The PL of the Er atom at 1.54 [micro]m has been studied versus the process parameters and so as a function of the different AlN morphologies. It was shown that the maximum of PL emission is achieved for a rate of 1 atomic %. PL intensity was shown to increase with the magnetron power and decrease with the polarization intensity of the substrates. These two results demonstrate that PL intensity is strongly correlated to the matrix morphology. The larger the crystallites, the most efficient are the PL emission allows evidencing the role of the non radiative defects crystalline fields in the crystallites. The role of the defects was confirmed by time resolved photoluminescence measurements and by PL measurements performed on annealed samples or at low temperature. The decrease of PL with temperature is very weak, making this way the material very promising for optoelectronic and photonic applications
LHOMER, CHRISTOPHE. "Proprietes electriques et optiques de terres rares (yb, er) dans les semiconducteurs iii-v. Mecanisme d'excitation de la luminescence". Rennes, INSA, 1991. http://www.theses.fr/1991ISAR0006.
Texto completoNascimento, Cristiane. "Propriétés structurales et optiques de verres et couches minces borates des systèmes TR : Y2O3-Al2O3-B2O3 ET TR:Y2O3-CaO-B2O3 (TR=Nd, Er)". Université Joseph Fourier (Grenoble), 2007. http://www.theses.fr/2007GRE10101.
Texto completoLn this work, we studied the structural and luminescent properties of rare earth (RE) doped amorphous borate materials containing yttrium, where RE = Nd'+, Er'+. For this purpose, bulk glasses and amorphous thin films ofthe systems Y,O, - Al,O, - B,O, (Y ALB) and Y,O, - CaO - B,O, (YCAB) were produced and their properties were investigated by thermal analysis (OTA, OSC, TG), x-ray diffraction, vibration al spectroscopy measurements (Raman and infrared reflectance), photoluminescence and m-lines spectroscopy. The bulk samples were synthesized by the conventional melting/molding method and the multilayer thin films were obtained by spin-coating sol-gel solutions. The Y ALB g1asses exhibited a higher glass transition temperature (Tg) than the YCAB glasses, 707 - 717°C and 613 - 649°C, respectively. The YALB xerogels obtained from the sol-gel solutions also presented a Tg, between 713-716°e. The glasses and thin films presented a complex borate structure, composed by a variety of superstructural units, such as metaborate rings and chains, pyroborate and orthoborate units. We found that the erbium doped glas ses and thin films presented a broad band emission of about 54 - 66 nm for the 411312 , > 4115/2 transition (1530 - 1535 nm). A maximum radiative lifetime of 425 Jls was obtained for the less doped glass samples (0,1 mol%). The neodymium doped glasses also presented a large bandwidth (38 nm), larger than values found for phosphate glasses (21-25 nm). The m-lines spectroscopy showed that the erbium glassy thin films behave as planar monomode waveguides when deposited on silica substrates, and the obtained refraction indices were about 1,59 - 1,65
Ma, Lidong. "Investigation of multicolored and white light emission from IR-excited nano-particles:". Thesis, Boston College, 2021. http://hdl.handle.net/2345/bc-ir:109229.
Texto completoThesis advisor: Pradip Bakshi
The search for multicolored light produced by some IR laser-excited luminescent nano-powders has revealed, for laser power exceeding a threshold value, the emission of white light (WL) with black-body characteristics. I am directing my research to the study of the physical parameters that may influence the threshold power of the laser and the efficiency of the WL emission. A typical compound that I will investigate will consist of nano-powders of SrZrO3 doped with Yb. The parameters of relevance may include Yb concentration, pressure, temperature, size of nano-crystals, exciting power and wavelength of the laser, dynamical parameters such as decay and build-up patterns. The aim of my research will be both theoretical and experimental: theoretical for I will try to uncover the mechanism of the WL production and experimental for the possible application as efficient light sources of systems similar to the ones that I will investigate (oxide nano-powders doped with lanthanide or transition metal ions). The “new” light sources in the market (fluorescence lights sources, and LED lamps) beat the Edison bulbs in efficiency, but they do not produce the black-body emission of the Edison bulbs that is most pleasing to the eye. The search for efficient black-body type of sources is still on and we want to be a part of it
Thesis (PhD) — Boston College, 2021
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Physics
Milori, Debora Marcondes Bastos Pereira. "Caracterização do LiNbO3:Er+3 como meio ativo para lasers de estado sólido através dos espectros de absorção/emissão polarizada e medida dos tempos de vida de luminescência". Universidade de São Paulo, 1989. http://www.teses.usp.br/teses/disponiveis/54/54131/tde-19052009-104534/.
Texto completoThis work consists in the optical characterization of LiNbO3:Er3+ single crystals, aiming to verify the possibility of this system being an active media for laser. The absorption and emission results were satisfactory, being compatible enough with the theoretical model adopted. The luminescence lifetime of the 4S3/2 - 4I15/2 e 4F9/2 - 4I15/2 transitions was measured at the ambient and liquid nitrogen temperature, showing that they are possible candidates for laser transitions. The behavior of the undesirable OH- and Fe2+ impurities was also studied through thermal treatment. The control of these concentrations was done using the EPR and optical absorption techniques and the results showed it is possible to eliminate such impurities in a totally controlled way.
Klier, Dennis Tobias [Verfasser] y Michael Uwe [Akademischer Betreuer] Kumke. "Upconversion luminescence in Er-codoped NaYF4 nanoparticles : fundamental photophysics and optimization for life science applications / Dennis Tobias Klier ; Betreuer: Michael Uwe Kumke". Potsdam : Universität Potsdam, 2016. http://d-nb.info/1218401028/34.
Texto completoMorais, Evandro Augusto de [UNESP]. "Fotoluminescência e transporte elétrico em 'SNO IND. 2' dopado com os íons terras-raras 'ER POT. 3'/' e 'EU POT. 3'/'". Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/100909.
Texto completoCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Através do processo sol-gel, foi sintetizado o material semicondutor dióxido de estanho ('SNO IND. 2') dopado com as terras-raras 'ER' e 'EU', sendo obtidas amostras na forma de xerogéis (pós) e filmes finos, neste último caso pela técnica de emersão. A introdução das terras-raras provoca desordens estruturais no material e impede o crescimento dos cristalitos, cujo tamanho varia entre 5-20NM, devido a segregação dos terras-raras na superfície das partículas, o que está relacionado a sua baixa solubilidade em 'SNO IND. 2'. A análise das propriedades ópticas mostra emissão eficiente dos íons terras-raras 'ER POT. 3'/' e 'EU POT. 3'/' quando introduzidos nesta matriz. A emissão é confirmada tanto por excitação direta destes íons, como por processos de transferência de energia, tanto correspondente ao bandgap da matriz como a transição 'INTPOT. 2 F IND. 7/2 de íon 'YB POT. 3'/' em amostras codopadas com 'ER POT. 3'/' e 'YB POT. 3'/'. A análise por fotoluminescência permite distinguir terras-raras em sítios substitucionais a 'SN POT. 4'/' ou em centros na superfície das partículas. A investigação das propriedades elétricas mostra um aumento de resistividade de até seis ordens de magnitude em relação a filmes não dopados. Isto está relacionado com o carácter aceitador de íons 'ER POT. 3'/' e 'EU POT. 3'/' em 'SNO IND. 2', que é naturalmente tipo-N, oque acarreta alta compensação de carga e também barreiras de potencial intergranulares que diminuem a mobilidade eletrônica. Foi investidada também a captura de elétrons fotoexcitados por centros de 'ER' e 'EU' termicamente ativados. À medida que se aumenta a temperatura e a concentração de 'ER' e 'EU', maior é a taxa de captura. Do modelo proposto, foram obtidos parâmetros importantes, como de captura devido aos defeitos dominantes.
The semiconductor material tin dioxide ('SNO IND. 2') has been produced by the sol-gel process, doped with the rare-earth 'ER' and 'EU'. Samples are obtained in the from of xerogels (powder) and thin films, in this latter case by the dip-coating technique. The incorporation of rare-earth ions promotes structural disorder in the material, which avoids the crystallite growth due to segregation of rare-earth ions to the surface, which is related to the low solubility in the 'SNO IND. 2' matrix. The crystallite size is in the range 5-20NM. Analysis of optical properties shows efficient emission of rare-earth ions 'ER POT. 3'/' and 'EU POT. 3'/', whem introduced in this matrix. This emission is confirmed either by direct excitation of ions, as well as by energy transfer processes, corresponding to the matrix bandgap or to the transition 'INTPOT. 2 F IND. 7/2 of íon 'YB POT. 3'/' ion in samples codoped with 'ER POT. 3'/' and 'YB POT. 3'/'. Photoluminescence spectra allow distinguishing rare-earth ions in substitutional sites of 'SN' and particles surface located centers. Investigation of electrical properties show a resitivity increase up to 6 orders of magnitude compared to undoped films. This behavior is related with the acceptor like character of 'ER POT. 3'/' and 'EU POT. 3'/' in 'SNO IND. 2', which is naturally a N-type material, leading to a high charge compensation degree and also to intergrain potential barriers that decrease the electronic mobility. It has also been investigated the capture of photogenerated electrons by ER' and 'ER' thermally activated centers. When the temperature is raised or the ER' or 'EU' concentratin is increased the capture ratebecomes faster. From a proposed model, some very relevent parameters are obtained, scu as the capture barrier due to the dominating defect.
Morais, Evandro Augusto de. "Fotoluminescência e transporte elétrico em 'SN"O IND. 2' dopado com os íons terras-raras 'ER POT. 3'/' e 'EU POT. 3'/' /". Bauru : [s.n.], 2008. http://hdl.handle.net/11449/100909.
Texto completoBanca: Sandra Helena Pulcinelli
Banca: Giancarlo Esposito de Souza Brito
Banca: Ligia de Oliveira Ruggiero
Banca: Tomaz Catunda
O Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi da Unesp
Resumo: Através do processo sol-gel, foi sintetizado o material semicondutor dióxido de estanho ('SN"O IND. 2') dopado com as terras-raras 'ER' e 'EU', sendo obtidas amostras na forma de xerogéis (pós) e filmes finos, neste último caso pela técnica de emersão. A introdução das terras-raras provoca desordens estruturais no material e impede o crescimento dos cristalitos, cujo tamanho varia entre 5-20NM, devido a segregação dos terras-raras na superfície das partículas, o que está relacionado a sua baixa solubilidade em 'SN"O IND. 2'. A análise das propriedades ópticas mostra emissão eficiente dos íons terras-raras 'ER POT. 3'/' e 'EU POT. 3'/' quando introduzidos nesta matriz. A emissão é confirmada tanto por excitação direta destes íons, como por processos de transferência de energia, tanto correspondente ao bandgap da matriz como a transição 'INTPOT. 2 F IND. 7/2 de íon 'YB POT. 3'/' em amostras codopadas com 'ER POT. 3'/' e 'YB POT. 3'/'. A análise por fotoluminescência permite distinguir terras-raras em sítios substitucionais a 'SN POT. 4'/' ou em centros na superfície das partículas. A investigação das propriedades elétricas mostra um aumento de resistividade de até seis ordens de magnitude em relação a filmes não dopados. Isto está relacionado com o carácter aceitador de íons 'ER POT. 3'/' e 'EU POT. 3'/' em 'SN"O IND. 2', que é naturalmente tipo-N, oque acarreta alta compensação de carga e também barreiras de potencial intergranulares que diminuem a mobilidade eletrônica. Foi investidada também a captura de elétrons fotoexcitados por centros de 'ER' e 'EU' termicamente ativados. À medida que se aumenta a temperatura e a concentração de 'ER' e 'EU', maior é a taxa de captura. Do modelo proposto, foram obtidos parâmetros importantes, como de captura devido aos defeitos dominantes.
Abstract: The semiconductor material tin dioxide ('SN"O IND. 2') has been produced by the sol-gel process, doped with the rare-earth 'ER' and 'EU'. Samples are obtained in the from of xerogels (powder) and thin films, in this latter case by the dip-coating technique. The incorporation of rare-earth ions promotes structural disorder in the material, which avoids the crystallite growth due to segregation of rare-earth ions to the surface, which is related to the low solubility in the 'SN"O IND. 2' matrix. The crystallite size is in the range 5-20NM. Analysis of optical properties shows efficient emission of rare-earth ions 'ER POT. 3'/' and 'EU POT. 3'/', whem introduced in this matrix. This emission is confirmed either by direct excitation of ions, as well as by energy transfer processes, corresponding to the matrix bandgap or to the transition 'INTPOT. 2 F IND. 7/2 of íon 'YB POT. 3'/' ion in samples codoped with 'ER POT. 3'/' and 'YB POT. 3'/'. Photoluminescence spectra allow distinguishing rare-earth ions in substitutional sites of 'SN' and particles surface located centers. Investigation of electrical properties show a resitivity increase up to 6 orders of magnitude compared to undoped films. This behavior is related with the acceptor like character of 'ER POT. 3'/' and 'EU POT. 3'/' in 'SN"O IND. 2', which is naturally a N-type material, leading to a high charge compensation degree and also to intergrain potential barriers that decrease the electronic mobility. It has also been investigated the capture of photogenerated electrons by "ER' and 'ER' thermally activated centers. When the temperature is raised or the "ER' or 'EU' concentratin is increased the capture ratebecomes faster. From a proposed model, some very relevent parameters are obtained, scu as the capture barrier due to the dominating defect.
Doutor
Legrand, Jérémy. "Étude de la photoluminescence de films d'AlN dopé erbium (AlN-Er) déposés par PVD magnétron RF". Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0186/document.
Texto completoDuring the last decades, rare-earth-doped III-V thin films have been the subject of growing interest and the topic of many studies. Because III-V nitrides possess a direct gap, they are suitable host matrices to allow rare-earth (RE) luminescence. Thereby, by combining the III-V and the RE characteristics, it becomes possible to consider promising applications in the optoelectronic field. In this study, erbium (Er) was chosen because of its emission both in the visible and in the infrared range. In this work, Er-doped AlN thin films were prepared in an experimental PVD sputtering magnetron radiofrequency reactor. During the deposition, an applied negative bias on the substrate allowed to obtain different kinds of crystalline morphology of the deposited layers, which were studied by several characterization techniques such as AFM, DRX, ellipsometry, MEB, MET. Luminescence properties of the films were investigated both experimentally and with an optical model by photoluminescence (light excitation) spectroscopy. Experimental measurements by cathodoluminescence (electronic excitation) spectroscopy were also performed. This thesis aimed to optimize the elaboration process and the material and to get a better understanding of the influence of AlN host matrix crystalline morphology on the erbium luminescence efficiency. The AlN:Er system stood as a model system and the obtained results could be extended to the other RE
Steveler, Émilie. "Etude des mécanismes de photoluminescence dans les nitrures et oxydes de silicium dopés aux terres rares (Er, Nd)". Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0109/document.
Texto completoThis thesis is devoted to the study of radiative transitions in rare-earth (Er, Nd) doped silicon oxide and silicon nitride thin films. The optical characterization of thin films prepared by thermal evaporation is based on photoluminescence spectroscopy. In this work, we investigate indirect excitation processes of Er3+ and Nd3+ ions in silicon based materials. In silicon nitride and silicon oxinitride, an energy transfer leading to the indirect excitation of Er3+ ions is demonstrated. For amorphous samples, the sensitization of Er3+ ions is attributed to localized electronic states in the matrix bandgap. For samples annealed at high temperature, silicon nanocrystals play a major role in the indirect excitation of erbium. In silicon oxide thin films, we evidences that both direct and indirect excitation processes of Nd3+ ions occur. For amorphous samples, indirect excitation occurs thanks to localized electronic states in the matrix bandgap. For samples annealed at temperatures above 1000 °C, silicon nanocrystals are sensitizers of Nd3+ ions. Results suggest that indirect excitation thank to localized states in the matrix bandgap could be more efficient than indirect excitation thanks to silicon nanocrystals
Câmara, Sarita Silva. "Propriedades luminescentes Upconversion do YVO4:Er,Yb aplicadas ao estudo forense de resíduo de tiro". reponame:Repositório Institucional da UnB, 2014. http://repositorio.unb.br/handle/10482/16861.
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Este trabalho trata da avaliação da utilização do ortovanadato de ítrio dopado com Er3+ e Yb3+ como marcador luminescente upconversion para a identificação de resíduo de tiro (GSR) e codificação de munições. O YVO4: 2% Er3+,Yb3+ foi sintetizado por combustão, variando-se a concentração de itérbio entre 0,5 e 8 mol%. Este material foi caracterizado por difração de raios X de pó, microscopia eletrônica de varredura, espectroscopia por dispersão de energia e espectroscopia de fluorescência, e apresentou resultados satisfatórios para ser incorporado em munições a fim de possibilitar a identificação dos GSR e codificar munições. Os materiais sintetizados com maiores concentrações de itérbio apresentaram maiores intensidades de luminescência por upconversion, sendo possível identificar visualmente a luminescência do material tanto em processo downconversion (exc = 254 nm) quanto em processo up conversion (exc = 980 nm). A incorporação desse material nas munições e as análises dos resíduo de tiro gerados indicaram que o YVO4:Er3+,Yb3+ possui as características necessárias para serem utilizados como marcadores de GSR, tais como a alta estabilidade térmica e a elevada intensidade luminescente. Também foi possível identificar visualmente a luminescência das partículas coletadas nos resíduos de tiro (exc = 254 e 980 nm). Além das propriedades ópticas, o YVO4:Er3+,Yb3+ impõe uma assinatura química aos resíduos de tiro, permitindo a sua identificação inequívoca. Estes resultados evidenciaram que o sistema YVO4:Er3+,Yb3+ apresenta alto potencial para ser utilizado como marcador para munição, de forma isolada ou associada a outro marcador - o que permite não só a identificação dos resíduos de tiro como também a codificação de munições. ______________________________________________________________________________ ABSTRACT
This work is about the evaluation of using yttrium orthovanadate doped with Er3+ and Yb3+ as an upconverting luminescent taggant for identifying gunshot residue (GSR) and encoding ammunition. The YVO4: 2% Er3+,Yb3+ was synthesized by combustion process varying the concentration of ytterbium between 0.5 and 8 mol%. This material was characterized by X-ray diffraction powder, scanning electron microscopy, energy dispersive spectroscopy and fluorescence spectroscopy, and good results were achieved in order to incorporate this material as GSR taggants and ammunition encoders. The materials synthesized with higher concentrations of ytterbium showed higher intensities of upconversion luminescence, and it was possible to visually identify the luminescence of the material in both processes such as downconversion (exc = 254 nm) and upconversion ((exc = 980 nm). The incorporation of this material in ammunition and analysis of the gunshot residues indicated that YVO4:Er3+,Yb3+ has the characteristics necessary to be used as a GSR taggant, such as high thermal stability and high luminescence intensity. It was also possible to visually identify the luminescence of the particles collected in gunshot residue (exc = 254 e 980 nm). Besides the optical properties, the YVO4:Er3+,Yb3+ imposes a chemical signature on GSR, allowing their unequivocal identification. These results showed that the YVO4:Er3+,Yb3+ system has a high potential to be used as ammunition taggant, both isolated or associated with other taggantes. This fact allows both the identification of gunshot residue and ammunition encoding.
Ravaro, Leandro Piaggi [UNESP]. "Influência da acidez da suspensão coloidal para a geração de defeitos pontuais e emissão no infra vermelho em SnO2 dopado com Er". Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/106659.
Texto completoDióxido de estanho (snO2) é um semicondutor óxido do tipo-n, que é transparente na região do ultravioleta/visível. Possui muitas aplicações como, por exemplo, eletrodos transparente, sensores de gás, coletores e dispositivos optoeletrônicos. Quando dopado com íons terras-raras, SnO2 pode ser utilizado na confecção de dispositivos para comunicação óptica, principalmente na forma de filmes finos. A modificação do pH da suspensão coliodal, a partir do pH neutro, mostrou-se um artifício eficaz no controle das propriedades ópticas, elétricas e estruturais das amostras obtidas sem a necessidade da utilização de compostos orgânicos para a estabilização do sistema coloidal e controle do tamanho da partícula. O pH ácido favorece a formação de ligações cruzadas (Sn-O-Sn) entre as partículas, com geração de aglomerados maiores observados nas medidas de MEV/FEG e maior concentração de defeitos superficiais identificados pelos modos de vibração S1 e S2 do espectro Raman. O pH ácido também reduz a resistividade, a energia de ativação e a energia de captura dos filmes obtidos. O espectro de emissão para uma pastilha dopada com 2% de érbio, obtida com pH4, apresentou leve alteração das componentes dos níveis Stark referente aos íons Er3+ localizados na superfície desorganizada do grão. O processamento de filmes por litrografia positiva (lift-off) beneficiou a estabilidade elétrica e a reprodutividade de dados em medidas elétricas, facilitando a interferência dos resultados. Para medidas decaimento da condutividade foto-excitada com um LED de InGan (450 nm), foi possível observar valores positivo e negativo para a quantidade (Ecap-), indicando regiões distintas de temperatura com domínio da captura de elétrons por defeitos ou da mobilidade eletrônica
Tin dioxide (SnO2) is an n-type semiconductor, which is transparent in the ultraviolet/visible range. It has many applications, such as transparent electrodes, gas sensors, solar collectors and optoelectronic devices. When doped with rare-earth ions, SnO2 may be used for building optical communication devices, mainly in the form of thin films. Modification of pH of colloidad supension from neutral pH has shown an efficient tool on the control of optical, electrical and structural properties, which can be obtained without requirement of using organic compounds for stabilization of colloidal system and particle size control. Acid pH favors the formation of cross-linked bonds (Sn-O-Sn) between particles, with gernation of larger agglomerates, as observed in the SEM/FEG images and higher concentration of surface defects as identified by the vibration modes S1 and S2 of the Raman spectra. The acid pH also reduces the resitivity, the activation energy of the deeper energy level and the capture energy of obtained films. The emission spectra for a 2%Re3+- doped pellet, obtained with pH4, presents a slight variation of the Stark levels related to Er3+ ion located at the disorganized grain surface. Film processing by lift-off photolighography has led to electrical stability and data reproducibility in electrical measurements, helping the results interpretation. For measurements of decay of conductivity photo-induced by an InGaN LED (450nm), it was possible to observe positivo as well a negative values for the quantity (Ecap-), indicating distinct regions of temperature, either dominated by the electron capture by defects or by electronic mobility
Ravaro, Leandro Piaggi. "Influência da acidez da suspensão coloidal para a geração de defeitos pontuais e emissão no infra vermelho em SnO2 dopado com Er /". Bauru, 2013. http://hdl.handle.net/11449/106659.
Texto completoBanca: Fenelon Martinho Lima Pontes
Banca: Jose Humberto Dias da Silva
Banca: Andrea Simone Stucchi de Camargo Alvarez Bernardez
Banca: Virgilio de Carvalho dos Anjos
O Programa de Pós Graduação em Ciência e Tecnologia de Materiais, PosMat , tem carater institucional e integra as atividades de pesquisa em materiais de diversos campi
Resumo: Dióxido de estanho (snO2) é um semicondutor óxido do tipo-n, que é transparente na região do ultravioleta/visível. Possui muitas aplicações como, por exemplo, eletrodos transparente, sensores de gás, coletores e dispositivos optoeletrônicos. Quando dopado com íons terras-raras, SnO2 pode ser utilizado na confecção de dispositivos para comunicação óptica, principalmente na forma de filmes finos. A modificação do pH da suspensão coliodal, a partir do pH neutro, mostrou-se um artifício eficaz no controle das propriedades ópticas, elétricas e estruturais das amostras obtidas sem a necessidade da utilização de compostos orgânicos para a estabilização do sistema coloidal e controle do tamanho da partícula. O pH ácido favorece a formação de ligações cruzadas (Sn-O-Sn) entre as partículas, com geração de aglomerados maiores observados nas medidas de MEV/FEG e maior concentração de defeitos superficiais identificados pelos modos de vibração S1 e S2 do espectro Raman. O pH ácido também reduz a resistividade, a energia de ativação e a energia de captura dos filmes obtidos. O espectro de emissão para uma pastilha dopada com 2% de érbio, obtida com pH4, apresentou leve alteração das componentes dos níveis Stark referente aos íons Er3+ localizados na superfície desorganizada do grão. O processamento de filmes por litrografia positiva (lift-off) beneficiou a estabilidade elétrica e a reprodutividade de dados em medidas elétricas, facilitando a interferência dos resultados. Para medidas decaimento da condutividade foto-excitada com um LED de InGan (450 nm), foi possível observar valores positivo e negativo para a quantidade (Ecap-), indicando regiões distintas de temperatura com domínio da captura de elétrons por defeitos ou da mobilidade eletrônica
Abstract: Tin dioxide (SnO2) is an n-type semiconductor, which is transparent in the ultraviolet/visible range. It has many applications, such as transparent electrodes, gas sensors, solar collectors and optoelectronic devices. When doped with rare-earth ions, SnO2 may be used for building optical communication devices, mainly in the form of thin films. Modification of pH of colloidad supension from neutral pH has shown an efficient tool on the control of optical, electrical and structural properties, which can be obtained without requirement of using organic compounds for stabilization of colloidal system and particle size control. Acid pH favors the formation of cross-linked bonds (Sn-O-Sn) between particles, with gernation of larger agglomerates, as observed in the SEM/FEG images and higher concentration of surface defects as identified by the vibration modes S1 and S2 of the Raman spectra. The acid pH also reduces the resitivity, the activation energy of the deeper energy level and the capture energy of obtained films. The emission spectra for a 2%Re3+- doped pellet, obtained with pH4, presents a slight variation of the Stark levels related to Er3+ ion located at the disorganized grain surface. Film processing by lift-off photolighography has led to electrical stability and data reproducibility in electrical measurements, helping the results interpretation. For measurements of decay of conductivity photo-induced by an InGaN LED (450nm), it was possible to observe positivo as well a negative values for the quantity (Ecap-), indicating distinct regions of temperature, either dominated by the electron capture by defects or by electronic mobility
Doutor
OLIVEIRA, Alexandre Miranda de. "Síntese e caracterização de compostos do sistema x/2 Al²O³-x/2 Y²O³ (100 - x) SiO² (x=10,20,30,40 e 50) dopados com Er³+ para aplicação em fotônica". Universidade Federal de Goiás, 2010. http://repositorio.bc.ufg.br/tede/handle/tde/809.
Texto completoThis work is to study the crystallization of compounds in the form of post system alumina-yttria-silica prepared by sol-gel mixed methodology and Pechini. Powders (x / 2) Y ² ³ - (X / 2) Al ² O ³ - (1-x) SiO ² (x = 0.1 0.2, 0.3, 0.4 and 0.5 mol) were doped with erbium prepared and characterized. The physical properties of composite SiO ² ¹ YO-, 5 - AlO ¹, 5 were studied by x-ray diffraction, FTIR spectroscopy, thermogravimetry, differential thermal analysis and photoluminescence measurements. It was possible to maintain the amorphous compositions at high temperatures, no crystallization below 900 ° C and the formation of phase Y ² ² O7 Si at 1100 ° C. We obtained a reasonable life time of some compositions treated at 1000 ° C. We observed the emission of green upconversion to excite the samples with high power laser. All synthesized samples exhibit photoluminescence emission and have maximum emission at 1530 nm with a width of ~ 47nm. This broad issue is a desirable property for amplifiers used in systems division multiplexing wavelengths (WDM) and suggests that Er ³ + ions are hosted in the amorphous phase.
Neste trabalho estudo-se a cristalização de compostos na forma de pós do sistema alumina-ítria-sílica preparados pela metodologia mista sol-gel e Pechini. Pós de (x/2) Y²O³-(X/2) Al²O³-(1-x) SiO² (x=0,1 0,2, 0,3, 0,4 e 0,5 em mol) dopados com érbio foram preparados e caracterizados. As propriedades físicas dos composto de SiO²-YO¹,5- AlO¹,5 foram estudadas por difração de raios-x, espectroscopia FTIR, termogravimetria, análise térmica diferencial e medidas de fotoluminescência. Foi possível manter as composições amorfas a altas temperaturas, não houve cristalização abaixo de 900° C e a formação da fase Y²Si²O7 a 1100 °C. Obtivemos um tempo de vida razóavel de algumas composições tratadas a 1000°C. Observamos a emissão verde de upconversion ao excitar as amostras com laser de alta potência. Todas as amostras sintetizadas apresentam emissão fotoluminescente e possuem máximo de emissão em 1530 nm com largura a meia altura de ~47nm. Essa emissão larga é uma propriedade desejável para amplificadores usados em sistemas de multiplexação por divisão de comprimentos de onda (WDM) e sugere que os íons Er³+ estão hospedados na fase amorfa.
Durand, Alexandre. "Contribution à l'étude cristallochimique et optique de silicates et germanates de terres rares appartenant aux systèmes Na2O-(M,M1)III2O3 (M, M'=Nd, Eu, Gd, Er, Al, Bi;X=Si, Ge)-matériaux luminescents et scintillateurs". La Rochelle, 2002. http://www.theses.fr/2002LAROS082.
Texto completoVetrone, Fiorenzo. "Luminescence spectroscopy of Er³⁺ doped inorganic nanocrystals : an investigation into their upconversion properties". Thesis, 2005. http://spectrum.library.concordia.ca/8450/1/NR04038.pdf.
Texto completoJiang, Ping-Ju y 江秉儒. "Room-temperature luminescence study of Er-doped porous silicon processed by rapid thermal oxidization". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/69999370934019477315.
Texto completo國立交通大學
光電工程系所
93
We successfully employed rapid thermal oxidized porous silicon (PS) to create silicon nanocrystals (nc-Si). In order to observe the size and the characteristics, experiments on different samples were investigated via transmission electron microscope (TEM)、Raman scattering and photoluminescence. After that, we doped Er ions into silicon rich SiO2 (SRSO) structure and successfully observed the infrared photoluminescence at 1.54μm from Er ions. The relations between infrared photoluminescence and average size of nc-Si were discussed in this study. In this work, we controlled different current density to vary the silicon porosity. The different average size of nc-Si were formed by changing the silicon porosity and rapid thermal oxidization. We observe the red-shift of Raman scattering and the blue-shift of visible photoluminescence from the average size of nc-Si. The intensity of infrared photoluminescence at 1.54μm from Er ions would increase as the decreasing of the average size of nc-Si. This fact means that the Er ions are excited by energy transfer process from the excited nc-Si and the conversion efficiency has relations with the average size of nc-Si.
Rinkel, Thorben. "Untersuchung der Keimbildung und Fluoreszenz von NaYF4:Yb,Er-Nanopartikeln mit Größen von unter 10nm". Doctoral thesis, 2016. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2016021814264.
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