424 results on '"Optoelectrónica"'
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2. A complete introduction through up conversion photoluminescence and its mechanisms.
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Dost Mohammadi, Afshin and Jarollahi, Hanie
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PHOTOLUMINESCENCE ,HETEROSTRUCTURES - Abstract
Copyright of Latin-American Journal of Physics Education is the property of Latin-American Physics Education Network and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
3. A complete introduction through up conversion photoluminescence and its mechanisms.
- Author
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Mohammadi, Afshin Dost and Jarollahi, Hanie
- Subjects
PHOTOLUMINESCENCE ,LINEAR momentum ,OPTOELECTRONICS - Abstract
Copyright of Latin-American Journal of Physics Education is the property of Latin-American Physics Education Network and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
4. Optical Sensing Using Hybrid Multilayer Grating Metasurfaces with Customized Spectral Response
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Hamdy Mohamed Elshorbagy, Mahmoud, Cuadrado Conde, Alexander, Alda Serrano, Javier, Hamdy Mohamed Elshorbagy, Mahmoud, Cuadrado Conde, Alexander, and Alda Serrano, Javier
- Abstract
Submission received: 18 January 2024 / Revised: 30 January 2024 / Accepted: 1 February 2024 / Published: 5 February 2024, Customized metasurfaces allow for controlling optical responses in photonic and optoelectronic devices over a broad band. For sensing applications, the spectral response of an optical device can be narrowed to a few nanometers, which enhances its capabilities to detect environmental changes that shift the spectral transmission or reflection. These nanophotonic elements are key for the new generation of plasmonic optical sensors with custom responses and custom modes of operation. In our design, the metallic top electrode of a hydrogenated amorphous silicon thin-film solar cell is combined with a metasurface fabricated as a hybrid dielectric multilayer grating. This arrangement generates a plasmonic resonance on top of the active layer of the cell, which enhances the optoelectronic response of the system over a very narrow spectral band. Then, the solar cell becomes a sensor with a response that is highly dependent on the optical properties of the medium on top of it. The maximum sensitivity and figure of merit (FOM) are SB = 36,707 (mA/W)/RIU and ≈167 RIU−1, respectively, for the 560 nm wavelength using TE polarization. The optical response and the high sensing performance of this device make it suitable for detecting very tiny changes in gas media. This is of great importance for monitoring air quality and thecomposition of gases in closed atmospheres., Ministerio de Economía y Competitividad de España, Comunidad de Madrid (España), Depto. de Óptica, Sección Deptal. de Óptica (Óptica), Fac. de Óptica y Optometría, TRUE, pub
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- 2024
5. Análisis del diseño de interfaces gráficas de usuario para el control y monitorización de sistemas optoelectrónicos aplicados a telecomunicaciones e instrumentación electrónica.
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Galvis, J. E., Puerto, K., Galvis, L. N., and Ramírez, J.
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SYSTEM integration , *GRAPHICAL user interfaces , *COMPUTER engineering , *COMPUTER equipment , *OPTICAL fiber communication , *TELECOMMUNICATION systems , *BIBLIOGRAPHIC databases , *OPTOELECTRONIC devices - Abstract
The analysis of the use of graphical user interfaces (GUI) applied to the optical-electronic systems for telecommunications and instrumentation allows observing the existing possibilities in the integration of engineering systems with computer equipment to facilitate access to information and optimize human/machine interaction in the different scenarios of the industries that are currently being developed. Through the use of academic databases, indexed and accepted by the scientific community, a total of sixty bibliographic references oriented to the design and implementation of graphical user interfaces developed at an international level in Colombia, and the region of Norte de Santander were consulted, analyzing the different programming environments and the expected usability in the control and monitoring of optoelectronic systems. It is observed that there is a boom in the use of open license programming environments and that researchers tend to integrate multiple development platforms to take advantage of the characteristics of each one of them. [ABSTRACT FROM AUTHOR]
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- 2022
- Full Text
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6. Temporal behavior and processing of the LiDAR signal in fog
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Universitat Politècnica de Catalunya. Doctorat en Enginyeria Òptica, Universitat Politècnica de Catalunya. Centre de Desenvolupament de Sensors, Instrumentació i Sistemes, Universitat Politècnica de Catalunya. Departament d'Òptica i Optometria, Universitat Politècnica de Catalunya. GREO - Grup de Recerca en Enginyeria Òptica, Ballesta Garcia, Maria, Rodríguez Aramendia, Ana, García Gómez, Pablo, Rodrigo Arcay, Noel, Royo Royo, Santiago, Universitat Politècnica de Catalunya. Doctorat en Enginyeria Òptica, Universitat Politècnica de Catalunya. Centre de Desenvolupament de Sensors, Instrumentació i Sistemes, Universitat Politècnica de Catalunya. Departament d'Òptica i Optometria, Universitat Politècnica de Catalunya. GREO - Grup de Recerca en Enginyeria Òptica, Ballesta Garcia, Maria, Rodríguez Aramendia, Ana, García Gómez, Pablo, Rodrigo Arcay, Noel, and Royo Royo, Santiago
- Abstract
The interest in LiDAR imaging systems has recently increased in outdoor ground-based applications related to computer vision, in fields like autonomous vehicles. However, for the complete settling of the technology, there are still obstacles related to outdoor performance, being its use in adverse weather conditions one of the most challenging. When working in bad weather, data shown in point clouds is unreliable and its temporal behavior is unknown. We have designed, constructed, and tested a scanning-pulsed LiDAR imaging system with outstanding characteristics related to optoelectronic modifications, in particular including digitization capabilities of each of the pulses. The system performance was tested in a macro-scale fog chamber and, using the collected data, two relevant phenomena were identified: the backscattering signal of light that first interacts with the media and false-positive points that appear due to the scattering properties of the media. Digitization of the complete signal can be used to develop algorithms to identify and get rid of them. Our contribution is related to the digitization, analysis, and characterization of the acquired signal when steering to a target under foggy conditions, as well as the proposal of different strategies to improve point clouds generated in these conditions., This work was supported by the Spanish Ministry of Science and Innovation (MICINN) under the project PID2020-119484RB-I00. The first author gratefully acknowledges the Universitat Politècnica de Catalunya and Banco Santander for the financial support of her predoctoral research grant., Peer Reviewed, Postprint (author's final draft)
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- 2023
7. Analysis of the spectral response of fractal antennas related with its geometry and current paths
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Cuadrado, Alexander, López-Alonso, José Manuel, Martínez Antón, Juan Carlos, Ezquerro Rodríguez, José Miguel, González, Francisco Javier, Alda, Javier, Cuadrado, Alexander, López-Alonso, José Manuel, Martínez Antón, Juan Carlos, Ezquerro Rodríguez, José Miguel, González, Francisco Javier, and Alda, Javier
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ISBN: 978-162841713-5 CODEN: PSISD Copyright 2015 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited., Fractal antennas have been proposed to improve the bandwidth of resonant structures and optical antennas. Their multiband characteristics are of interest in radiofrequency and microwave technologies. In this contribution we link the geometry of the current paths built-in the fractal antenna with the spectral response. We have seen that the actual currents owing through the structure are not limited to the portion of the fractal that should be geometrically linked with the signal. This fact strongly depends on the design of the fractal and how the different scales are arranged within the antenna. Some ideas involving materials that could actively respond to the incoming radiation could be of help to spectrally select the response of the multiband design., Ministerio de Economia y Competitividad (MINECO), Centro Mexicano de Innovación en Energía Solar from Fondo Sectorial CONACYT-Secretaría de Energía Sustentabilidad Energética, National Laboratory program from CONACYT through the Terahertz Science and Technology National Lab (LANCYTT), Sección Deptal. de Óptica (Óptica), Fac. de Óptica y Optometría, TRUE, pub
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- 2023
8. Method for the characterization of Fresnel lens flux transfer performance
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Martínez Antón, Juan Carlos, Vázquez Moliní, Daniel, Muñóz de la Luna, Javier, Gómez Pedrero, José Antonio, Álvarez Fernández-Balbuena, Antonio, Martínez Antón, Juan Carlos, Vázquez Moliní, Daniel, Muñóz de la Luna, Javier, Gómez Pedrero, José Antonio, and Álvarez Fernández-Balbuena, Antonio
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ISBN: 978-081948795-7 CODEN: PSISD Copyright 2011 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited., Fresnel lenses and other faceted or micro-optic devices are increasingly used in multiple applications like solar light concentrators and illumination devices, just to name some representative. However, it seems to be a certain lack of adequate techniques for the assessment of the performance of final fabricated devices. As applications are more exigent this characterization is a must. We provide a technique to characterize the performance of Fresnel lenses, as light collection devices. The basis for the method is a configuration where a camera images the Fresnel lens aperture. The entrance pupil of the camera is situated at the focal spot or the conjugate of a simulated solar source. In this manner, detailed maps of the performance of different Fresnel lenses are obtained for different acceptance angles., Sección Deptal. de Óptica (Óptica), Fac. de Óptica y Optometría, TRUE, pub
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- 2023
9. Estimation of the influence of finite dielectric substrates on the far-field pattern of an array of metallic scatterers in the infrared
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Rico-García, José María, López-Alonso, José Manuel, Alda, Javier, Rico-García, José María, López-Alonso, José Manuel, and Alda, Javier
- Abstract
Es una versión postprint., The far-field scattered in the infrared by an arrangement of metallic structures deposited on a dielectric wafer is estimated in this paper. The scattering is modelled by using operators that describe the far field obtained under the regime applicable for the Babinet's principle in its vectorial approach and the Stratton–Chu approximation. The far-field scattered by an arrangement of thin gold layers over a dielectric wafer under infrared illumination is computed. The model assumes a normally incident vectorial Gaussian beam focused over the arrangement plane. An angular spectrum decomposition of the field is done. Then, every plane wave is scattered by the whole structure: arrangement + substrate layer. The reflexions in the substrate layer and the arrangement action have been taken into account in an operator formalism. Numerical results estimating the influence of substrate thickness on the pattern are obtained., Ministerio de Ciencia y Tecnologı́a de España, Sección Deptal. de Óptica (Óptica), Fac. de Óptica y Optometría, TRUE, pub
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- 2023
10. Boosting terahertz generation in laser-field ionized gases using a sawtooth wave shape
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González de Alaiza, Pedro, Babushkin, Ihar, Bergé, Luc, Skupin, Stephan, Cabrera Granado, Eduardo, Köhler, Christian, Mörgner, Uwe, Husakou, Anton V., Herrmann, Jens, González de Alaiza, Pedro, Babushkin, Ihar, Bergé, Luc, Skupin, Stephan, Cabrera Granado, Eduardo, Köhler, Christian, Mörgner, Uwe, Husakou, Anton V., and Herrmann, Jens
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© 2015 American Physical Society, Broadband ultrashort terahertz (THz) pulses can be produced using plasma generation in a noble gas ionized by femtosecond two-color pulses. Here we demonstrate that, by using multiple-frequency laser pulses, one can obtain a waveform which optimizes the free electron trajectories in such a way that they acquire the largest drift velocity. This allows us to increase the THz conversion efficiency to 2%, an unprecedented performance for THz generation in gases. In addition to the analytical study of THz generation using a local current model, we perform comprehensive 3D simulations accounting for propagation effects which confirm this prediction. Our results show that THz conversion via tunnel ionization can be greatly improved with well-designed multicolor pulses., DFG, Sección Deptal. de Óptica (Óptica), Fac. de Óptica y Optometría, TRUE, pub
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- 2023
11. Robust fitting of Zernike polynomials to noisy point clouds defined over connected domains of arbitrary shape
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Rodríguez Ibáñez, Diego, Gómez Pedrero, José Antonio, Alonso Fernández, José, Quiroga Mellado, Juan Antonio, Rodríguez Ibáñez, Diego, Gómez Pedrero, José Antonio, Alonso Fernández, José, and Quiroga Mellado, Juan Antonio
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En abierto en la web del editor. Received 7 Oct 2015; revised 4 Feb 2016; accepted 9 Feb 2016; published 9 Mar 2016 © 2016 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited., A new method for fitting a series of Zernike polynomials to point clouds defined over connected domains of arbitrary shape defined within the unit circle is presented in this work. The method is based on the application of machine learning fitting techniques by constructing an extended training set in order to ensure the smooth variation of local curvature over the whole domain. Therefore this technique is best suited for fitting points corresponding to ophthalmic lenses surfaces, particularly progressive power ones, in non-regular domains. We have tested our method by fitting numerical and real surfaces reaching an accuracy of 1 micron in elevation and 0.1 D in local curvature in agreement with the customary tolerances in the ophthalmic manufacturing industry., Ministerio de Economía y Competitividad (MINECO), Depto. de Óptica, Sección Deptal. de Óptica (Óptica), Fac. de Ciencias Físicas, Fac. de Óptica y Optometría, TRUE, pub
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- 2023
12. Phase imaging and detection in pseudo-heterodyne scattering scanning near-field optical microscopy measurements
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Moreno, Camilo, Alda, Javier, Kinzel, Edward, Boreman, Glenn, Moreno, Camilo, Alda, Javier, Kinzel, Edward, and Boreman, Glenn
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En O.A. en la web del editor. Received 19 October 2016; revised 20 December 2016; accepted 3 January 2017; posted 5 January 2017 (Doc. ID 279131); published 27 January 2017, When considering the pseudo-heterodyne mode for detection of the modulus and phase of the near field from scattering scanning near-field optical microscopy (s-SNOM) measurements, processing only the modulus of the signal may produce an undesired constraint in the accessible values of the phase of the near field. A two-dimensional analysis of the signal provided by the data acquisition system makes it possible to obtain phase maps over the whole [0, 2, Ministerio de Economía y Competitividad de España (MINECO), University of North Carolina at Charlotte, Sección Deptal. de Óptica (Óptica), Fac. de Óptica y Optometría, TRUE, pub
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- 2023
13. Characterization of spatial–temporal patterns in dynamic speckle sequences using principal component analysis
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López Alonso, José Manuel, Grumel, Eduardo, Cap, Nelly Lucía, Trivi, Marcelo, Rabal, Héctor, Alda Serrano, Javier, López Alonso, José Manuel, Grumel, Eduardo, Cap, Nelly Lucía, Trivi, Marcelo, Rabal, Héctor, and Alda Serrano, Javier
- Abstract
En abierto en la web del editor. Received Mar. 9, 2016; accepted for publication May 6, 2016; published online Jun. 7, 2016. This paper was a derivation of our previous conference contribution titled “Characterization of dynamic speckle sequences using principal component analysis and image descriptors.”, Speckle is being used as a characterization tool for the analysis of the dynamics of slow-varying phenomena occurring in biological and industrial samples at the surface or near-surface regions. The retrieved data take the form of a sequence of speckle images. These images contain information about the inner dynamics of the biological or physical process taking place in the sample. Principal component analysis (PCA) is able to split the original data set into a collection of classes. These classes are related to processes showing different dynamics. In addition, statistical descriptors of speckle images are used to retrieve information on the characteristics of the sample. These statistical descriptors can be calculated in almost real time and provide a fast monitoring of the sample. On the other hand, PCA requires a longer computation time, but the results contain more information related to spatial–temporal patterns associated to the process under analysis. This contribution merges both descriptions and uses PCA as a preprocessing tool to obtain a collection of filtered images, where statistical descriptors are evaluated on each of them. The method applies to slow-varying biological and industrial processes., Ministerio de Economia y Competitividad (MINECO), CONICET, CIC, UNLP Argentina, Sección Deptal. de Óptica (Óptica), Fac. de Óptica y Optometría, TRUE, pub
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- 2023
14. Visible-light-control of dielectric permittivity in ferroelectrics with charged domain walls
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Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. CEMAD - Caracterització Elèctrica de Materials i Dispositius, Ordóñez Pimentel, Jonathan, García García, José Eduardo, da Silva Jr, Paulo Sergio, Venet, Michel, Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. CEMAD - Caracterització Elèctrica de Materials i Dispositius, Ordóñez Pimentel, Jonathan, García García, José Eduardo, da Silva Jr, Paulo Sergio, and Venet, Michel
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Optical control of functional properties in ferroic materials is now a highly appealing topic because it may entail different paradigms for future technologies. In ferroelectrics, in particular, controlling the properties with light implies noncontact external control of the material’s functionality, thereby opening a pathway for developing the next generation of photocontrolled devices. Recently, experimental observations have demonstrated that the dielectric permittivity of charged-domain-wall ferroelectrics can be easily modulated by visible light. However, because of the wide band gap of ferroelectric materials, the physical origin of this phenomenon is still controversial. Here, the photoinduced electronic reconstruction mechanism is proposed as the primary light-absorption mechanism in charged domain walls, allowing an understanding of the origin of the visible-light control of dielectric permittivity in ferroelectric materials., Postprint (author's final draft)
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- 2023
15. Síntesis y caracterización de nuevos óxidos metálicos para dispositivos Optoelectrónicos
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Canosa Romano, Carlos, Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, and Villalobos, Crisanto José
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β-Ga2O3 ,Metall-òxid-semiconductors -- Aplicacions industrials ,optoelectronics ,Enginyeria electrònica::Optoelectrònica [Àrees temàtiques de la UPC] ,Metal oxide semiconductors -- Spectra ,Enginyeria dels materials::Materials funcionals::Materials òptics [Àrees temàtiques de la UPC] ,Optoelectronics -- Equipment and supplies -- Materials -- Testing ,optoelectrònica ,Metal oxide semiconductors -- Industrial applications ,TCO ,Optoelectrònica -- Aparells i accesoris -- Materials -- Proves ,Metall-òxid-semiconductors -- Espectres ,PLD ,optoelectrónica - Abstract
En el presente trabajo de fin de máster se ha realizado un estudio sobre un nuevo óxido metálico transparente semiconductor, el β-Ga2O3, que es susceptible de integración en dispositivos optoelectrónicos para la optimización de sus características. El β-Ga2O3 es un material semiconductor de banda ancha cuyas propiedades, junto con la relativa facilidad de preparación, lo convierten en un punto de reciente atracción para la investigación tanto fundamental como aplicada, así se puede observar en los índices de publicaciones en el área de ingeniería. En el estudio se han depositado capas de óxido de gálio mediante la técnica de deposición física en fase de vapor, esepcíficamente, PLD (deposición por láser pulsado) sobre sustratos de Al-Si-B (comercialmente conocido como Corning) y en presencia de una atmósfera oxidente. Se ha generado una matriz de ocho condiciones de deposición mediante la variación de la presión parcial de oxigeno en la cámara y la temperatura del sustrato, para tratar de encontrar las condiciones óptimas de crecimiento de las capas delgadas y propiedades ópticas y estructurales. Las diferentes condiciones de deposición han sido: (C1) 0,1mbar y 350ºC, (C2) 0,1mbar y 400ºC, (C3) 0,1mbar y 450ºC, (C4) 0,1mbar y 500ºC, (C5) 0,4mbar y 350ºC, (C6) 0,4mbar y 400ºC, (C7) 0,4mbar y 450ºC, (C8) 0,4mbar y 500ºC. Tras la sintetización de las capas delgadas en función de la condición de deposición, se han carectirizado las muestras mediante: difracción por rayos X (XRD), Espectroscopía Raman, Espectroscopía de fotoelectrones de rayos X (XPS), Microscopía electrónica de barrido de emisión de campo (FESEM), Microscopía confocal y transmisión de ondas. Finalmente, se ha llevado a cabo un análisis de los resultados obtenidos para determinar la película cuya condición presenta una mayor calidad y transparencia. Los diversos ensayos realizados sobre las muestras han revelado que se ha logrado depositar y sintetizar con éxito el óxido de galio en fase beta en su fase cristalina cúbica y en concreto para la condición C2 la fase cristalina monoclínica. Por otra parte, se ha detectado que existe una relación de correlación fuertemente lineal entre las relaciones estequiométricas de los compuestos y la absorbancia (a mayor proporción de galio mayor absorbancia). Para todos los compuestos sintetizados, se han podido observar valores de absorbancia muy parecidos a los del sustrato sobre el que se ha depositado, lo que implica una muy buena transparencia de las capas. Por último, el tipo de crecimiento de capas hallado ha sido del tipo mixto y las imágenes FESEM de las capas muestras unos espesores compactos, sin defectos ni heterogeneidades, debido a la técnica PLD En el present treball de fi de màster s'ha realitzat un estudi sobre un nou òxid semiconductor transparent, el β-Ga2O3, que és susceptible d'integració en dispositius optoelectrònics per optimitzar-ne les característiques. El β-Ga2O3 és un material semiconductor de banda ampla, les propietats del qual, juntament amb la relativa facilitat de preparació, el converteixen en un punt de recent atracció per a la recerca, tant fonamental com aplicada, així es ho reflecteixen el índexs de publicacions a l'àrea enginyeria. A l'estudi s'han dipositat capes d'òxid de gal·li mitjançant la tècnica de deposició física en fase de vapor, específicament, PLD (deposició per làser polsat) sobre substrats d'Al-Si-B (comercialment conegut com a Corning) i en presència d'una atmosfera oxidant. S'ha generat una matriu de vuit condicions de deposició mitjançant la variació de la pressió parcial d'oxigen a la cambra i la temperatura del substrat, per intentar trobar les condicions òptimes de creixement de les capes primes, així com de les propietats òptiques i estructurals. Les diferents condicions de deposició han estat: (1) 0,1mbar i 350ºC, (2) 0,1mbar i 400ºC, (3) 0,1mbar i 450ºC, (4) 0,1mbar i 500ºC, (5) 0, 4mbar i 350ºC, (6) 0,4mbar i 400ºC, (7) 0,4mbar i 450ºC, (8) 0,4mbar i 500ºC. Després de la sinterització de les capes primes en funció de la condició de deposició, s'han caracteritzat les mostres mitjançant: difracció per raigs X (XRD), Espectroscòpia Raman, Espectroscòpia de fotoelectrons de raigs X (XPS), Microscòpia electrònica de rastreig d’emissió de camp (FESEM), Microscòpia confocal i transmissió d'ones. Finalment, s'ha realitzat una anàlisi dels resultats obtinguts per determinar la pel·lícula amb aquella condició que presenta una millor qualitat i transparència. Els diversos assaigs realitzats en les mostres han revelat que s'ha aconseguit dipositar i sintetitzar amb èxit l'òxid de gal·li en fase beta a la fase cristal·lina cúbica i en concret per a la condició 2 la fase cristal·lina monoclínica. D'altra banda, s'ha detectat que hi ha una relació de correlació fortament lineal entre les relacions estequiomètriques dels compostos i l'absorbància (a major proporció de gal·li major absorbància). Per a tots els compostos sintetitzats, s'han pogut observar valors d'absorbància molt semblants als del substrat sobre el qual s'ha dipositat, cosa que implica una transparència molt bona de les capes. Finalment, el tipus de creixement de capes trobat ha estat del tipus mixt i les imatges FESEM de les capes mostren uns gruixos compactes, sense defectes ni heterogeneïtats, a causa de la tècnica PLD In the present master's thesis, a study has been carried out on a new semiconducting transparent metal oxide, β-Ga2O3, which is susceptible to be integrated in a variety of optoelectronic devices for the optimization of its characteristics. The β-Ga2O3 is a wide bandgap semiconductor material whose properties, together with the relative ease of preparation, makes it a point of recent attraction for both fundamental and applied research, as can be seen in the indexes of publications in the engineering area. In the study, gallium oxide layers have been deposited by means of the physical vapor deposition technique, specifically PLD (pulsed laser deposition) on Al-Si-B substrates (commercially known as Corning) and in the presence of an oxidizing atmosphere. A matrix of eight deposition conditions has been generated by varying the oxygen partial pressure in the chamber and the substrate temperature, in order to find out the optimum conditions for thin film growth, optical and structural properties. The following deposition conditions have been used: (1) 0.1mbar and 350ºC, (2) 0.1mbar and 400ºC, (3) 0.1mbar and 450ºC, (4) 0.1mbar and 500ºC, (5) 0.4mbar and 350ºC, (6) 0.4mbar and 400ºC, (7) 0.4mbar and 450ºC, (8) 0.4mbar and 500ºC. After synthesizing the thin films according to the deposition condition, the samples have been characterized by: X-ray diffraction (XRD), Raman Spectroscopy, X-ray photoelectron spectroscopy (XPS), Field Emission Scanning Electron Microscopy (FESEM), Confocal and Transmission Wave Microscopy. Finally, an analysis of the results obtained has been carried out to determine the film with the highest quality and transparency. The various tests carried out on the samples, have revealed that the gallium oxide in beta phase has been successfully deposited and synthesized in its cubic crystalline phase and specifically for condition 2 the monoclinic crystalline phase. On the other hand, it has been detected that there is a strongly linear relationship between the stoichiometric ratios of the compounds and the absorbance (the higher the proportion of gallium, the higher the absorbance). For all the compounds synthesized, it has been possible to observe absorbance values very similar to those of the substrate on which they have been deposited, which implies a very good transparency of the layers. Finally, the type of layer growth found has been of the mixed type and the FESEM images of the layers show compact thicknesses, without defects or heterogeneities, due to the PLD technique
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- 2023
16. Inkjet‐Printed p‐NiO/n‐ZnO Heterojunction Diodes for Photodetection Applications
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Sergio González, Giovanni Vescio, Juan Luis Frieiro, Alina Hauser, Flavio Linardi, Julian López‐Vidrier, Marek Oszajca, Sergi Hernández, Albert Cirera, and Blas Garrido
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Mechanics of Materials ,Mechanical Engineering ,Oxides ,Optoelectronics ,Òxids ,Optoelectrònica ,Light emitting diodes ,Díodes electroluminescents - Abstract
Transparent Conducting Oxides (TCOs) are an enticing family of optoelectronic materials which have been proven to increase efficiency when incorporated into perovskite light emitting diode (PE-LED) and organic OLED architectures as transport layers. Solution-processed metal oxide inks have already been demonstrated, although there is still a need for high-quality inkjet-printable metal oxide inks with a thermal post-process below 200 °C. The set of inks in this work are adapted from low-boiling point colloidal suspensions of metal oxide nanoparticles synthesized via flame spray pyrolysis. High quality, pinhole- and wrinkle-free inkjet-printed layers are obtained at low temperatures through vacuum oven post process, as proven by scanning electron microscopy. The crystallinity of the layers is confirmed by X-ray diffraction, showing the expected hexagonal and cubic structures respectively for ZnO and NiO. The thin film layers reach over 70% (ZnO) and 90% (NiO) transparency in the visible spectrum. Their implementation in the inkjet-printed p-n diode shows excellent I-V rectifying behavior with an ON/OFF ratio of two orders of magnitude at ±3 V and a forward threshold voltage of 2 V. Furthermore, the device exhibits an increase in photocurrent around four orders of magnitude when illuminated under a 1-sun solar simulator.
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- 2023
17. Visible-Light-Control of Dielectric Permittivity in Ferroelectrics with Charged Domain Walls
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Jonathan Ordoñez-Pimentel, José E. García, Paulo S. da Silva, Michel Venet, Universitat Politècnica de Catalunya. Departament de Física, and Universitat Politècnica de Catalunya. CEMAD - Caracterització Elèctrica de Materials i Dispositius
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Ferroelectrics ,Photoinduced effect ,Ferroelectric domains ,Física [Àrees temàtiques de la UPC] ,Ferroelectricity ,Permittivity ,Light-matter interaction ,General Physics and Astronomy ,Optoelectronics ,Domain walls ,Ferroelectricitat ,Optoelectrònica - Abstract
Optical control of functional properties in ferroic materials is now a highly appealing topic because it may entail different paradigms for future technologies. In ferroelectrics, in particular, controlling the properties with light implies noncontact external control of the material’s functionality, thereby opening a pathway for developing the next generation of photocontrolled devices. Recently, experimental observations have demonstrated that the dielectric permittivity of charged-domain-wall ferroelectrics can be easily modulated by visible light. However, because of the wide band gap of ferroelectric materials, the physical origin of this phenomenon is still controversial. Here, the photoinduced electronic reconstruction mechanism is proposed as the primary light-absorption mechanism in charged domain walls, allowing an understanding of the origin of the visible-light control of dielectric permittivity in ferroelectric materials.
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- 2023
18. Low toxicity metal halide semiconductors for optoelectronics and thermoelectrics
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Sebastiá Luna, Paz, Bolink, Henk, Palazón Huet, Francisco, and Institut de Ciència Molecular
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semiconductores ,materiales ,LEDs ,fotovoltaica ,UNESCO::QUÍMICA ,termoeléctrica ,optoelectrónica - Abstract
Amb la finalitat de lluitar contra el canvi climàtic i donar suport a les energies renovables i no contaminants, l'objectiu principal d'aquesta tesi és la cerca i l'estudi de nous materials amb potencial aplicació en tres grans àrees d'investigació: la fotovoltaica, la termoelèctrica i els díodes emissors de llum (LED). Atés que molts dels materials emprats en aquestes àrees contenen components tòxics i nocius per al medi ambient, els materials desenvolupats en aquesta tesi a més presenten una baixa toxicitat i es poden preparar mitjançant mètodes de síntesis i deposició més sostenibles i ecològics. Concretament, es van utilitzar dos mètodes de síntesis: la mecanosíntesi en sec per molta de boles i la deposició en buit amb una sola font. Aquests mètodes són preferits perquè són més nets i generen menys residus que els mètodes de síntesis tradicionals, com la síntesi química en solució. En el Capítol 3 es presenten dues famílies d'halurs inorgànics de coure, els quals van demostrar tindre potencial per al seu ús en LEDs. Aquests compostos de coure presenten emissió de llum verda o blava, depenent de l'halur utilitzat. Un dels compostos, Cs3Cu2I5, va demostrar ser particularment interessant a causa de la seua alta eficiència en el blau. El Capítol 4 se centra en un compost de plata i bismut, comunament conegut com a doble perovskita. En particular, la doble perovskita Cs2AgBiBr6 es va modificar per a reduir la seua banda prohibida (o bandgap) i millorar així la seua aplicabilitat en fotovoltaica. Es van provar diferents dopants i es va demostrar que les capes fines dopades amb estany aconseguien la major reducció del bandgap. Finalment, en el Capítol 5, es van estudiar tres espècies diferents en el sistema Cs-Sn-I per a aplicacions termoelèctriques. Es va demostrar que la fase beta CsSnI3 va aconseguir una major eficiència i es va mantindre estable en condicions inertes durant més d'una setmana. Així doncs, els resultats d'aquesta tesi tenen implicacions importants per a la indústria de l'optoelectrònica i la termoelèctrica, a més de demostrar la importància d'utilitzar mètodes de síntesis i deposició més sostenibles i ecològics per a la reducció de l'impacte ambiental d'aquestes àrees.////Con el fin de luchar contra el cambio climático y apoyar las energías renovables y no contaminantes, el objetivo principal de esta tesis es la búsqueda y el estudio de nuevos materiales con potencial aplicación en tres grandes áreas de investigación: la fotovoltaica, la termoeléctrica y los diodos emisores de luz (LED). Dado que muchos de los materiales empleados en estas áreas contienen componentes tóxicos y dañinos para el medio ambiente, los materiales desarrollados en esta tesis además presentan una baja toxicidad y se pueden preparar mediante métodos de síntesis y deposición más sostenibles y ecológicos. Concretamente, se utilizaron dos métodos de síntesis: la mecanosíntesis en seco por molienda de bolas y la deposición en vacío con una sola fuente. Estos métodos son preferidos porque son más limpios y generan menos residuos que los métodos de síntesis tradicionales, como la síntesis química en solución. En el Capítulo 3 se presentan dos familias de haluros inorgánicos de cobre, los cuales demostraron tener potencial para su uso en LEDs. Estos compuestos de cobre presentan emisión de luz verde o azul, dependiendo del haluro utilizado. Uno de los compuestos, Cs3Cu2I5, demostró ser particularmente interesante debido a su alta eficiencia en el azul. El Capítulo 4 se centra en un compuesto de plata y bismuto, comúnmente conocido como doble perovskita. En particular, la doble perovskita Cs2AgBiBr6 se modificó para reducir su banda prohibida (o bandgap) y mejorar así su aplicabilidad en fotovoltaica. Se probaron diferentes dopantes y se demostró que las capas finas dopadas con estaño conseguían la mayor reducción del bandgap. Por último, en el Capítulo 5, se estudiaron tres especies diferentes en el sistema Cs-Sn-I para aplicaciones termoeléctricas. Se demostró que la fase beta CsSnI3 logró una mayor eficiencia y se mantuvo estable en condiciones inertes durante más de una semana. Así pues, los resultados de esta tesis tienen implicaciones importantes para la industria de la optoelectrónica y la termoeléctrica, además de demostrar la importancia de utilizar métodos de síntesis y deposición más sostenibles y ecológicos para la reducción del impacto ambiental de estas áreas. In order to fight against climate change and support renewable and non-polluting energies, the main objective of this thesis is the search and study of new materials with potential application in three main research areas: photovoltaics, thermoelectrics and light-emitting diodes (LEDs). Since many of the materials used in these areas contain toxic and environmentally harmful components, the materials developed in this thesis also have low toxicity and can be prepared by more sustainable and environmentally friendly synthesis and deposition methods. Specifically, two synthesis methods were used: dry mechanosynthesis by ball milling and single-source vacuum deposition. These methods are preferred because they are cleaner and generate less waste than traditional synthesis methods such as solution-based chemical synthesis. Chapter 3 presents two families of inorganic copper halides, which were shown to have potential for use in LEDs. These copper compounds emit green or blue light, depending on the halide used. One of the compounds, Cs3Cu2I5, proved to be particularly interesting due to its high blue efficiency. Chapter 4 focuses on a silver-bismuth compound, commonly known as double perovskite. In particular, the double perovskite Cs2AgBiBr6 was modified to reduce its bandgap and thus improve its applicability in photovoltaics. Different dopants were tested and it was shown that tin-doped thin films achieved the highest bandgap reduction. Finally, in Chapter 5, three different species in the Cs-Sn-I system were studied for thermoelectric applications. It was shown that the beta phase CsSnI3 achieved higher efficiency and remained stable under inert conditions for more than one week. Thus, the results of this thesis have important implications for the optoelectronics and thermoelectric industries, as well as demonstrating the importance of using more sustainable and environmentally friendly synthesis and deposition methods for the reduction of environmental impact in these areas.
- Published
- 2023
19. Optoelectronic refractometric sensing device for gases based on dielectric bow-ties and amorphous silicon solar cells
- Author
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Mahmoud H. Elshorbagy, Óscar Esteban, Alexander Cuadrado, and Javier Alda
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Óptica geométrica e instrumental ,Multidisciplinary ,Óptica física, óptica cuántica ,Optoelectrónica ,Materiales ópticos - Abstract
The transformation of an hydrogenated amorphous silicon solar cell (aSiH) into an optoelectronic refratometric sensor has been possible through the addition of dielectric bow-tie resonant structures. The indium transparent oxide top electrode is replaced by a thin metallic layer to selectively prevent the direct transmission of light to the active layer of the cell. Then, an array of dielectric bow-tie structures is placed on top of this electrode, to activate the optical absorption through surface plasmon resonance (SPR). The whole device is exposed to the analyte under measure, which is the surrounding medium. Three different dielectric materials with low, medium, and high refractive index were selected for the bow-ties, namely magnesium fluoride (MgF$$_2$$ 2 ), silicon dioxide (SiO$$_2$$ 2 ), and aluminum nitride (AlN) have been tested as coupling structure for SPR excitation. The maximization of the readout/short circuit current has been achieved through the geometrical parameters of such structure. We have selected the geometrical parameters to maximize the short circuit current delivered by the a-Si cell at a given selected wavelength. The design has been customized to gas measurements application, where the index of refraction is slightly above 1 around 10$$^{-4}$$ - 4 . Our analysis reveals ultra-high sensitivity of $$2.4 \times 10^4$$ 2.4 × 10 4 (mA/W)/RIU, and a figure of merit FOM= 107 RIU$$^{-1}$$ - 1 , when the bow-tie is made of SiO$$_2$$ 2 . A performance rally competitive with those previously reported in literature, with the additional advantage of circunventing both moving parts and spectral interrogation elements.
- Published
- 2022
20. Diseño de una rejilla de Bragg con desplazamiento de fase mediante el algoritmo de búsqueda armónica
- Author
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Peña Pachacama, Luis Adrián, Montenegro Martínez, Gabriela Alexandra, and Tipán Simbaña, Milton Napoleón
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ÍNDICE DE REFRACCIÓN ,TELECOMUNICACIONES ,OPTOELECTRÓNICA ,DISEÑO EN INGENIERÍA ,ANÁLISIS ARMÓNICO ,ALGORITMOS - Abstract
En esteartículounarejilladeBraggdefibracon cambiodefaseesdiseñada,usandoelmétodode la matrizdetransferenciayoptimizadamediante el algoritmodebúsquedaarmónicaparareducirlos lóbulos secundariosdesuespectro,paraellouna caracterización delosparámetrosdelarejillaydel algoritmo sonrealizados.Losresultadosmuestranuna mejora deaproximadamente 12 vecesenlafunción de costo. In thisarticleaphase-shiftedfiberBragggrating is designed,usingthetransfermatrixmethodand optimized bytheharmonicsearchalgorithmtore- duce thesecondarydatalobesofitsspectrum,for this acharacterizationoftheparametersisthegrid and ofthealgorithmaremade.Theresultsshowan improvementofapproximatelytwelvefoldinthecost function.
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- 2022
21. Diseño de una rejilla de Bragg Chirp mediante el algoritmo de búsqueda armónica
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Llumiquinga Hernández, Giomara Abigail, Rimacuna Pahuanquiza, Luis Rolando, and Tipán Simbaña, Milton Napoleón
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ÍNDICE DE REFRACCIÓN ,TELECOMUNICACIONES ,OPTOELECTRÓNICA ,DISEÑO EN INGENIERÍA ,ANÁLISIS ARMÓNICO ,ALGORITMOS - Abstract
El diseñodesistemasWDMrequierenseparaciones de laslongitudesdeondacadavezmásreducidas porloqueparaevitarinterferenciasenlasseñales transmitidas lapotenciadelóbuloslateralesdelos espectrosópticosnecesitanreducirse.Enesteartículo, se presentaelusodelalgoritmodebúsquedaarmónica para optimizarlospicosdeloslóbuloslateralesa nivelesdeseadosdelespectrodereflexiónópticode una ChirpFBG.Losresultadosmuestranquelos parámetros delalgoritmoluegodesucaracterización son HMS = 13, HMCR = 0.93 y PAR = 0.3, consiguiéndose unamejoradeaproximadamente130 vecesconlosparámetrosestablecidosinicialmente. The designofWDMsystemsrequiressmallerand smaller wavelengthspacingssothattoavoidinterfer- ence inthetransmittedsignalsthesidelobepowerof the opticalspectraneedstobereduced.Inthispaper, the useoftheharmonicsearchalgorithmtooptimize the sidelobepeakstodesiredlevelsoftheoptical reflection spectrumofaChirpFBGispresented.The results showthattheparametersofthealgorithmaf- ter characterizationare HMS = 13, HMCR = 0.93 and PAR = 0.3, achievinganimprovementofapprox- imately 130timeswiththeinitiallysetparameters.
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- 2022
22. Diseño inverso de una rejilla de fibra óptica de bragg uniforme mediante redes neuronales
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Yumisaca Moreno, Víctor Alejandro and Tipán Simbaña, Milton Napoleón
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TELECOMUNICACIONES ,FOTÓNICA ,FIBRA ÓPTICA ,OPTOELECTRÓNICA ,DISEÑO EN INGENIERÍA ,REDES NEURONALES - Abstract
El diseño de dispositivos fotónicos es un reto debido a su complejidad matemática, más aún cuando se desea realizar diseños inversos. En este artículo se propone el diseño inverso de una FBG uniforme con baja carga computacional mediante el entrenamiento de una red neuronal Feed Forward a través de sus espectros y predecir su longitud e índice de modulación. Los resultados muestran que con una sola capa oculta de 80 neuronas, un conjunto de 1000 espectros y la función de entrenamiento Fletcher-Powell Conjugate Gradient se consigue predecir correctamente hasta el 99.5% de las muestras. The design of photonic devices is challenging due to it is mathematical complexity, even more so when inverse designs are desired. This article proposes the inverse design of a uniform FBG with low computational load by training a Feed Forward neural network through their spectrums and predict their length and modulation index. The results show that with a single hidden layer of 80 neurons, a set of 1000 spectrums and the Fletcher-Powell Conjugate Gradient training function, it is able to correctly predict up to 99.5% of the samples.
- Published
- 2022
23. Ultracold dipolar bosons trapped in atomtronic circuits
- Author
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Universitat de Barcelona, Institut de Ciències Fotòniques (ICFO), Universitat Autònoma de Barcelona, Guilleumas Morell, Montserrat, Juliá-Díaz, Bruno, Rovirola Metcalfe, Marc, Universitat de Barcelona, Institut de Ciències Fotòniques (ICFO), Universitat Autònoma de Barcelona, Guilleumas Morell, Montserrat, Juliá-Díaz, Bruno, and Rovirola Metcalfe, Marc
- Abstract
We consider a ring-shaped triple-well potential with few polar bosons characterized by a long-range and anisotropic interaction. By diagonalizing the extended Bose-Hubbard Hamiltonian, that treats sites as macroscopic dipoles, we investigate the ground state properties of the system as we rotate the dipole angle and vary the on-site interaction strength. We find that the competition between dipole and on-site interaction lead to different ground states and that the entanglement between sites depends on the filling factor which can be fractional or integer, and whether the number of particles is odd or even. We further characterize the system by studying the condensed fraction and coherence properties.
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- 2022
24. Designing avionics for lasers & optoelectronics
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Chau, H. K., Boyle, I., Nisbet-Jones, P., Bridges, C. P., Chau, H. K., Boyle, I., Nisbet-Jones, P., and Bridges, C. P.
- Abstract
Unlike imagery-based Earth observation (EO) which has become very widely and cheaply available, gravity sensing EO has not yet emerged from its fundamental science roots. The challenge therefore is to develop gravity sensing instruments that can replicate the success of widespread imagery based EO. There are three main gravity sensing mechanisms under investigation: laser ranging (e.g., GRACE-FO [1]); atom interferometers, which measure gravitation perturbations to the wavefunctions of individual atoms; and ‘relativistic geodesy’ which uses atomic clocks to measure the gravitational curvature of spacetime. All three of these measurement systems use stabilised lasers as their main enabling technology. However traditional laboratory laser systems struggle to meet the robustness, reliability, or low size, weight, and power (SWaP) requirements for use in space. A demonstrator was build that adapted telecommunications industry COTS components, and software radio FPGA/DSP techniques, to develop a new all-fibre space-qualified stabilised laser systems for geodesy that have equivalent performance to laboratory systems. This instrument was used to develop a 780 nm laser system that is stabilised to the Rubidium D2 line - the stabilised laser most commonly required by the quantum and atomic sensing field achieving sufficiently high laser performance for the laser system to be immediately useful for quantum applications (stability: 1-10 kHz, accuracy: 1 MHz); and in an ultra-compact package that has the potential to be used in space (1 litre, 0.5 kg, 10 W) [2]. This paper reports on the current student work that advances the instrument further towards a flight payload – and key avionics design considerations for future researchers. This takes lessons learnt from the ESA ESEO software radio payload in utilising ECSS design practices [3] to fabricate a robust and modular avionics back-end board that can operate with numerous front-end laser or opto-electronics configurations for
- Published
- 2022
25. Ultracold dipolar bosons trapped in atomtronic circuits
- Author
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Rovirola Metcalfe, Marc, Universitat de Barcelona, Institut de Ciències Fotòniques (ICFO), Universitat Autònoma de Barcelona, Guilleumas Morell, Montserrat, and Juliá-Díaz, Bruno
- Subjects
Optical lattices ,Enginyeria electrònica::Optoelectrònica [Àrees temàtiques de la UPC] ,Optoelectronics ,extended Bose-Hubbard ,Optoelectrònica ,atomtronics - Abstract
We consider a ring-shaped triple-well potential with few polar bosons characterized by a long-range and anisotropic interaction. By diagonalizing the extended Bose-Hubbard Hamiltonian, that treats sites as macroscopic dipoles, we investigate the ground state properties of the system as we rotate the dipole angle and vary the on-site interaction strength. We find that the competition between dipole and on-site interaction lead to different ground states and that the entanglement between sites depends on the filling factor which can be fractional or integer, and whether the number of particles is odd or even. We further characterize the system by studying the condensed fraction and coherence properties.
- Published
- 2022
26. Polyconjugation for Organic Electronics
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Medina Rivero, Samara and Casado-Cordon, Juan
- Subjects
Moléculas orgánicas policonjugadas ,Conjugation ,Organic devices ,Optoelectrónica ,Oligómeros (Polímeros) - Abstract
Since the discovery of the semiconducting properties of π-conjugated organic oligomers and polymers, many efforts have been devoted to generating structural features that bring about new and outstanding properties for optoelectronics, spintronics and magnetic devices, non-linear optics, or singlet fission processes. In this sense, the play between the resonance and π-electron delocalization phenomena in π-conjugated organic materials is the origin of their semiconducting behavior. For this reason, establishing not only the electron delocalization mechanism and its extension, but also which factors disturb the π-electron density is of utmost importance to enhance the proper performance of the electronic devices and develop ad hoc synthesis for desired application. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.
- Published
- 2022
27. Investigation of the charge-transport and optoelectronic properties of carbazole-based macrocycles
- Author
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Badía-Dominguez, Irene, Yang, Anna, Moore, Jeffrey, Huang, Feihe, González Núñez, Raúl, Gámez-Valenzuela, Sergio, Hernández-Jolín, Víctor, Ruíz-Delgado, María del Carmen, and Ponce-Ortiz, Rocio
- Subjects
Compuestos macrocíclicos ,Dft calculations ,Organic electronics ,Estructura molecular ,Química física ,Electrónica orgánica ,Optoelectrónica ,Charge transport ,Macrocycles ,Semiconductores - Abstract
Molecular systems have proven to be efficient active materials in electronics, being possible alternatives to the inorganic semiconductors used nowadays in electronic devices. In this project, an experimental and theoretical study of two carbazole-based macrocycles is presented (Figure 1). Specifically, we investigated the impact of the inclusion of acetylene groups on the electronic and molecular structures of these macrocycles, as well as their potential as charge transporting materials. The first studied compound (Cz) is composed by four carbazole groups linked at their para position with respect to the nitrogen atom1.In the second compound (ACz), the carbazole units are connected through ethynylene groups2. For this study, Raman and UV-Vis absorption spectroscopies have been used in combination with theoretical calculations based on the density functional theory (DFT). In addition, the two studied compounds have been implemented in organic field-effect transistors (OFETs), to assess their potential as active materials in organic electronics. Overall, the inclusion of ethynylene groups as π-conjugated spacers is found to be a good strategy to improve the electronic delocalization in macrocycles. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
- Published
- 2022
28. 3D Positioning system with optical sensors using encoding techniques
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Aparicio Esteve, Elena, Ureña Ureña, Jesús, Hernández Alonso, Álvaro, Universidad de Alcalá. Departamento de Electrónica, and Universidad de Alcalá. Programa de Doctorado en Sistemas Electrónicos Avanzados. Sistemas Inteligentes
- Subjects
Diseño de circuitos ,Optoelectrónica ,Electrónica ,Electronics ,Localización en interiores - Abstract
Esta tesis doctoral se centra en el desarrollo y la mejora de los Sistemas de Posicionamiento Locales (LPS) en interiores, los cuales se utilizan en entornos no compatibles con señales GNSS (Global Navigation Satellite Systems) para localizar, seguir y guiar a personas, objetos o vehículos. Se han realizado numerosos estudios para llevar a cabo un sistema de posicionamiento en entornos interiores, donde las personas pasan aproximadamente el 80% de su tiempo. Algunas de las técnicas propuestas emplean diversas señales, como acústicas, de radiofrecuencia, mecánicas u ópticas, entre otras. Por su bajo coste, facilidad de integración en el entorno de trabajo y ausencia de riesgos para la salud, la tecnología óptica es una alternativa viable que ha comenzado a expandirse rápidamente. Esta tesis aporta propuestas que permiten establecer las bases para el desarrollo de un LPS óptico basado en técnicas de codificación y sensores QADA. Se han propuesto dos diseños: un LPS orientado a la privacidad, basado en un conjunto de cuatro LEDs transmisores, aunque fácilmente extensible a más emisores, que actúan como balizas en ubicaciones conocidas y un único sensor QADA que actúa como el receptor a posicionar; y un LPS centralizado basado en un conjunto de transmisores móviles y al menos dos receptores QADA colocados en ubicaciones conocidas. Se han estudiado los módulos transmisor y receptor. En concreto, se propone un esquema de codificación para la emisión del transmisor, que proporciona capacidad de acceso múltiple, así como robustez frente a bajas relaciones señal a ruido y condiciones adversas como los efectos de multicamino y cerca-lejos. Además, para mejorar las prestaciones de la propuesta sin aumentar significativamente el tiempo de emisión, se han analizado diferentes secuencias y sus longitudes, como los códigos LS (Loosely Synchronized) o las secuencias pseudoaleatorias (Kasami). Por otro lado, el módulo receptor está compuesto por un sensor QADA, una apertura cuadrada y una etapa de filtrado para reducir las interferencias no deseadas. El sensor QADA y la apertura se han modelado para, en primer lugar, analizar la influencia de la longitud de la apertura en la linealidad de las ecuaciones de estimación del punto imagen y, en segundo lugar, determinar los parámetros intrínsecos que modelan el receptor (longitud, altura, desalineación y descentrado de la apertura respecto al sensor QADA), de forma que se pueda implementar un algoritmo de calibración para mejorar la precisión del sistema propuesto. El LPS tiene como objetivo estimar la posición 3D de un objeto estático o en movimiento. Para ello, se diseñan varios algoritmos basados en técnicas de triangulación con determinación de ángulos de llegada (AoA) y técnicas homograficas que resuelven el problema de la perspectiva de n puntos (PnP) del sistema pin-hole propuesto. Todas las propuestas han sido verificadas mediante simulaciones y pruebas experimentales en una gran variedad de situaciones: utilizando luz visible o infrarroja, secuencias LS o Kasami, diferentes longitudes de apertura, distintas distancias entre transmisores y receptores, diferentes algoritmos de posicionamiento y varias rotaciones del receptor. Finalmente, las pruebas experimentales han demostrado que es posible posicionar con errores de menos de 5 centímetros.
- Published
- 2022
29. Algunas aplicaciones de los Vidrios Calcogenuros a la Nano-Optoelectrónica
- Author
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Blétry, J.
- Subjects
Chalcogenide glasses ,Crystallisation ,Nanotechnology ,Optoelectronics ,Vidrios de calcogenuro ,Cristalización ,Nanotecnología ,Optoelectrónica ,Clay industries. Ceramics. Glass ,TP785-869 - Abstract
Since the first application of chalcogenide glasses in xerography, they have found numerous applications in nanotechnology, due to the different electrical conductivity of their crystalline and amorphous phases, thus giving rise to the development of optoelectronic devices. The process takes place by a local amorphisation and re-crystallisation of a chalcogenide glassy film. The crystallised area is heated up to a temperature beyond its melting point through a laser, then his hottest spot is cooled down at a rate of 1010 - 1011 K/s, which is higher than the critical rate for the material to become amorphous. The optical reflectivity is then measured on the localised amorphous area and it is possible to extract the information registered through the whole material. Matsushita began with the manufacture of DVD and Intel and Samsung were the first to introduce RAM memories capable to reach much higher speeds needing of lower energy and delivering a higher density of information.La primera aplicación de los vidrios de calcogenuro tuvo lugar en el campo de la xerografía, pero ya en los años 60 encontraron utilidad en el campo de las nano-tecnologías aprovechando la diferencia de conductividad eléctrica entre una fase vítrea y otra cristalina de los mismos, lo que dio lugar a su primera incorporación en circuitos opto-electrónicos. El proceso tiene lugar por la amorfización y re-cristalización local de una capa de vidrio de calcogenuro. Se calienta localmente la capa cristalizada hasta una temperatura superior a su punto de fusión por medio de un impulso láser. Después del impulso láser la zona caliente se enfría con una velocidad del orden de 1010 - 1011 K/s, muy superior a la velocidad crítica de amorfización del calcogenuro, dando lugar a la formación en la matriz cristalizada de una marca amorfa con una conductividad eléctrica diferente. Mediante la medida de la reflectividad óptica es posible leer la información registrada en el disco. Fue primeramente la empresa MATSUSHITA la que comenzó la fabricación de DVD y posteriormente INTEL y SAMSUNG las que introdujeron nuevas memorias RAM capaces de alcanzar velocidades de conmutación más grandes con consumos eléctricos más bajos y densidades de información altísimas.
- Published
- 2009
30. Implementación de un sistema con Leds de alta luminiscencia para semaforización preventiva en zonas escolares
- Author
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Dora L. Castañeda T., Luisa F. Echeverri L., and Edwin L. Márquez S.
- Subjects
Semáforo ,leads de alta luminiscencia ,fuente switchada ,reductor ,sistema de control ,luminosidad ,optoelectrónica ,sector productivo ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Es este artículo se presenta la implementación de un semáforo preventivo de dos caras con leds de alta luiniscencia color amarillo, el cual se instala en onas escolares como una alternativa para disminuir la accidentalidad que se presenta en éstas, dado que los últimos reportes de accidentalidad de la Secretaria de Tránsito y Transporte del año 2006 muestran que un 35% de los accidentes ocurren en las afueras de los colegios. El sistema tiene adaptado en su interior una fuente switchada en modo Step-down (reductor); además un subsistema de control que trabaja de tal forma que hace que el semáforo funcione con 60 destellos por minuto alternados para las dos caras. Este semáforo ofrece 880.35 lumens más de luminosidad y un ahorro de 83,45% energía en comparación con el semáforo convencional de bombillo incandescente; logrando así que incursionemos en el área de la optoelectrónica para obtener nuevas aplicaciones dentro del sector productivo.
- Published
- 2009
31. Propiedades optoelectrónicas en perovskitas halogenadas y su aplicación en energía y sensores
- Author
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Rocío García Aboal
- Subjects
Fotocatalizador ,Combustibles solares ,Solar Fuels ,Sensors ,División de aguas ,Optical Cavity ,Photocatalyst ,Perovskita ,Optoelectrónica ,Monocristales ,Células solares ,Perovskite ,7. Clean energy ,QUIMICA ORGANICA ,Sensores ,Solar Cell ,13. Climate action ,Water Splitting ,Waveguide ,Cavidad óptica ,Guía de ondas ,Optoelectronics ,Single Crystal - Abstract
[ES] La creciente urbanización e industrialización de las sociedades en las últimas décadas han provocado una alta demanda de energía. No obstante, mientras no se desarrollen fuentes de energía renovables que se constituyan como un reemplazo plausible de las actuales, la liberación de gases de efecto invernadero y sus consecuencias sobre el cambio climático difícilmente serán atajadas. Por ello, se está llevando a cabo una intensa búsqueda de energías renovables para un futuro inmediato. En los últimos años, la perovskita ha alcanzado una gran popularidad, centrando numerosos esfuerzos de investigación debido a sus propiedades ópticas y eléctricas únicas. Como por ejemplo su alto coeficiente de absorción y su alta movilidad de carga. Esta tesis comprende seis artículos científicos en torno a las perovskitas. Por un lado, 3 trabajos estudian los fenómenos ópticos que ocurren en el seno del material, con la finalidad de lograr una mejor comprensión de éstos. Puesto que el conocimiento de estos fenómenos ópticos a nivel individual (cristales aislados) permite modular y adaptar su síntesis y morfología para aplicaciones determinadas. Por otro lado, las perovskitas han sido implementadas en distintos dispositivos para su aplicación en tres campos: fotocatálisis, sensores y fotovoltaica. Por primera vez, se ha logrado utilizar este material para la obtención de hidrógeno llevando a cabo la reacción en fase vapor. Asimismo, diversas composiciones de perovskita se han usado para decorar grafeno y detectar niveles traza de Compuestos Orgánicos Volátiles (COV) como benceno y tolueno. Y finalmente se ha desarrollado una estrategia para insertar en la estructura de la perovskita moléculas orgánicas, de forma que se permite una ampliación de la fotorespuesta en el espectro visible. Por lo tanto, las perovskitas se han implementado exitosamente en aplicaciones de diversa índole, constituyéndose como un material prometedor y fácilmente adaptable a los distintos requisitos de cada campo de estudio., [CAT] La creixent urbanització i industrialització de les societats durant les últimes dècades han provocat una alta demanda d'energia. No obstant això, fins que no es desenvolupen fonts d'energia renovables que puguen ser un reemplaçament plausible de les actuals, l'alliberament de gasos d'efecte hivernacle i les seues conseqüències sobre el canvi climàtic seran difícilment aturades. Per tant, s'està duent a terme una intensa cerca d'energies renovables per a un futur immediat. En els últims anys, la perovskita ha aconseguit una gran popularitat, centrant nombrosos esforços de recerca a causa de les seues propietats òptiques i elèctriques úniques. Per exemple, el seu al coeficient d'absorció i la seua alta mobilitat de càrrega. Aquesta tesi reuneix sis articles científics al voltant de les perovskites. Per una banda, 3 treballs estudien els fenòmens òptics que ocorren en el material, amb la finalitat d'assolir una major comprensió d'aquests. Donat que el coneixement d'aquests fenòmens òptics a nivell individual (cristalls aïllats) permeten modular i adaptar la seua síntesi i morfologia per a determinades aplicacions. Per altra banda, les perovskites han sigut implementats en diferents dispositius per a la seua aplicació en tres camps: fotocatàlisi, sensors i fotovoltaica. Per primera vegada, s'hi ha aconseguit utilitzar aquest material per a l'obtenció d'hidrogen duent a terme la reacció en fase vapor. Així mateix, diverses composicions de perovskita s'han utilitzat per a decorar grafè i detectar nivells traça de Compostos Orgànics Volàtils (COV) com benzè i toluè. I finalment s'ha desenvolupat una estratègia per a inserir en l'estructura de la perovskita molècules orgàniques, de forma que es permet una ampliació de la fotoresposta en l'espectre del visible. Per tant, les perovskites s'han implementat exitosament en aplicacions de diversa índole, constituint-se com un material prometedor i fàcilment adaptable als diferents requisits de cada camp d'estudi., [EN] During the last decades, the growing urbanization and industrialization result in a significant need for energy. However, since feasible renewable energy sources should be further developed to replace the current energy source, the release of greenhouse gases and their climate change consequences are difficult to overcome. For that reason, the development of renewable energy sources has been attracting growing research efforts. Recently, perovskites gathered great interest owing to their outstanding optical and electrical properties. For instance, their high absorption coefficient and superior charge mobility. This thesis comprises six scientific articles about perovskites. On one hand, 3 works study the optical phenomena that occur within the material in order to achieve a better understanding. The deep knowledge of these optical phenomena's at the individual level (isolated crystals) enable the modulation and tuning of their synthesis and morphology to match specific applications. On another hand, perovskites have been implemented in several devices for their application in three research fields: photocatalysis, sensors, and photovoltaic. For the first time, this nanomaterial was successfully employed for obtaining hydrogen carrying out the reaction in the vapor phase. Likewise, several perovskite compositions have been used for decorating graphene and detect trace levels of Volatile Organic Compounds (VOC) as benzene and toluene. And finally, it has been developed a strategy to insert organic molecules in the perovskite structure, resulting in an enhanced photoresponse in the visible range. Therefore, perovskites have been successfully implemented in several applications, becoming a promising material and easily adaptable to the different requirements needed in each field of study., Financial support from the Spanish Ministry of Economy and Competitiveness (Severo Ochoa, SEV-2016-0683), Intramural CSIC project 201680I006, and Fundación Ramón Areces (XVII Concurso Nacional para la adjudicación de Ayudas a la Investigación en Ciencias de la Vida y de la Materia) is gratefully acknowledged. This research was financially supported by the Spanish Ministry of Economy and Competitiveness (Mineco) of Spain (TQ2011-26455)2, MAT2015-69669-P, and regional government grant PrometeoII/2017/026. This work was supported by Spanish ministry of Economy, Industry and Competitiveness (MINECO) through the projects TEC2015-74405-JIN, MAT2015-69669-P as well as the regional projects of both Provincia Autonoma di Trento (PAT) of Italy, through the call Grandi Progetti 2012: SIQURO and the Comunidad Valenciana of Spain project PrometeoII/2014/026. This work was supported in part by MICINN and FEDER via grants no. RTI2018-101580- B-I00, by AGAUR under grant. 2017SGR418. S. R.-B. thanks the Research Executive Agency (REA) and the European Commission for the funding received under the Marie Skłodowska Curie actions (H2020-MSCA-IF-2015/Grant agreement number 709023/ZESMO). R. G. A. acknowledges the FPI scholarship from MINECO MAT2015-69669-P. P. A. acknowledges the financial support from the Spanish Government through ‘Severo Ochoa” (SEV-2016-0683, MINECO) and PGC2018-099744-B-I00 (MCIU/AEI/FEDER)
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- 2021
32. Comunicação entre veículos robóticos de sub-superfície
- Author
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Gambôa, Darso António Adão, Damas, Bruno Duarte, and Viegas, Vitor Manuel Rodrigues
- Subjects
Comunicação ótica sem fio subaquática ,veículos subaquáticos autónomos ,Engenharia e Tecnologia::Engenharia Eletrotécnica, Eletrónica e Informática [Domínio/Área Científica] ,modulação On-Off-keying ,optoelectrónica - Abstract
A forte atenuação dos sinais eletromagnéticos na água é a principal razão pela qual a exploração subaquática, a vigilância marítima e outras aplicações, atualmente dependem de cabos submarinos para enviar ou receber dados de um terminal de comunicação. Embora a comunicação acústica se tenha tornado o método de comunicação sem fios padrão para as aplicações subaquáticas devido ao seu longo alcance, elas incorrem em alto custo e têm baixas taxas de dados. A necessidade por comunicações de alto débito binário e largura de banda estimulou a exploração de métodos não acústicos que antes eram negligenciados devido às limitações de distância. Contrariamente aos sistemas acústicos e de radiofrequência, que apresentam limitações como custo, velocidade de propagação das ondas e largura de banda disponível, o que se traduz na taxa de transmissão de dados, a comunicação ótica sem fios é apresentada como solução alternativa para ultrapassar as limitações mencionadas. À vista disso, a solução proposta nesta dissertação baseia-se num sistema de comunicação ótica de baixo custo, viável para as comunicações sem fio subaquática à curta distância entre veículos não tripulados. Assim sendo, um sistema transmissor baseado em LED de alto brilho de 3𝑊 com uma faixa de comprimento de onda entre 460 – 470 𝑛𝑚 e um sistema recetor baseado em fotodíodo com uma sensibilidade espectral entre 400 – 1100 𝑛𝑚, foram desenvolvidos e testados em diferentes canais de comunicação, ao ar livre, num tanque de água doce e por fim na água do mar. O resultado das experiências com o protótipo mostrou com sucesso que, na presença da luz ambiente, a distância de transmissão - receção dos dados chega a 4,5 𝑚 e, na ausência da luz ambiente 5,50 𝑚 ambos com uma taxa de transmissão de 300 𝑏𝑝𝑠. Por fim, o trabalho apresenta sugestões para trabalhos futuros de modo a melhorar o desempenho, a eficiência e a robustez do sistema. The strong attenuation of electromagnetic signals in water is the main reason why underwater exploration, maritime surveillance and other applications currently rely on underwater cables to send or receive data from a communication terminal. Although acoustic communications have become the standard wireless communication method for underwater applications due to their long range, they incur high cost and have low data rates. The need for high data rate and bandwidth communications has stimulated the exploration of non-acoustic methods that were previously neglected due to distance limitations. Contrary to acoustic and radio-frequency systems, which present limitations such as cost, wave propagation speed and available bandwidth, which translates into data transmission rate, wireless optical communication is presented as an alternative solution to overcome the mentioned limitations. In view of this, the solution proposed in this dissertation is based on a low-cost optical communication system, feasible for underwater wireless communications at short distance between unmanned vehicles. Therefore, a transmitter system based on 3W high-brightness LED with a wavelength range between 460 - 470 nm and a receiver system based on photodiode with a spectral sensitivity between 400 - 1100 nm, were developed and tested in different communication channels, outdoors, in a freshwater tank and finally in seawater. The result of the experiments with the prototype successfully showed that, in the presence of ambient light, the data transmission-reception distance reaches 4,5 m and, in the absence of ambient light 5,50 m both with a transmission rate of 300 bps. Finally, the work presents suggestions for future work in order to improve the performance, efficiency and robustness of the system.
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- 2021
33. In-vivo Measurement of Wrist Movements During the Dart-Throwing Motion Using Inertial Measurement Units
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Gabriella Fischer, Maurizio Calcagni, Simone Balocco, Michael Alexander Wirth, University of Zurich, and Fischer, Gabriella
- Subjects
Wrist Joint ,Motion analysis ,1303 Biochemistry ,Inertial frame of reference ,Kinematics ,Computer science ,Movement ,Canell ,610 Medicine & health ,TP1-1185 ,3107 Atomic and Molecular Physics, and Optics ,Cinemàtica ,1710 Information Systems ,Biochemistry ,Motion capture ,Article ,Motion (physics) ,Analytical Chemistry ,range of motion ,Units of measurement ,Inertial measurement unit ,wrist ,Humans ,Computer vision ,Range of Motion, Articular ,Electrical and Electronic Engineering ,Optoelectronics ,10266 Clinic for Reconstructive Surgery ,Instrumentation ,1602 Analytical Chemistry ,business.industry ,3105 Instrumentation ,2208 Electrical and Electronic Engineering ,Chemical technology ,motion analysis ,inertial measurement units ,kinematics ,optoelectronic motion capture ,dart throwing motion ,activities of daily living ,Wrist ,Atomic and Molecular Physics, and Optics ,Biomechanical Phenomena ,Artificial intelligence ,Range of motion ,business ,Optoelectrònica - Abstract
Background: This study investigates the dart-throwing motion (DTM) by comparing an inertial measurement unit-based system previously validated for basic motion tasks with an optoelectronic motion capture system. The DTM is interesting as wrist movement during many activities of daily living occur in this movement plane, but the complex movement is difficult to assess clinically. Methods: Ten healthy subjects were recorded while performing the DTM with their right wrist using inertial sensors and skin markers. Maximum range of motion obtained by the different systems and the mean absolute difference were calculated. Results: In the flexion-extension plane, both systems calculated a range of motion of 100° with mean absolute differences of 8°, while in the radial-ulnar deviation plane, a mean absolute difference of 17° and range of motion values of 48° for the optoelectronic system and 59° for the inertial measurement units were found. Conclusions: This study shows the challenge of comparing results of different kinematic motion capture systems for complex movements while also highlighting inertial measurement units as promising for future clinical application in dynamic and coupled wrist movements. Possible sources of error and solutions are discussed., Sensors, 21 (16)
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- 2021
34. Propiedades optoelectrónicas en perovskitas halogenadas y su aplicación en energía y sensores
- Author
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Atienzar Corvillo, Pedro Enrique, Ramiro Manzano, Fernando, Universitat Politècnica de València. Instituto Universitario Mixto de Tecnología Química - Institut Universitari Mixt de Tecnologia Química, Generalitat Valenciana, Agencia Estatal de Investigación, Ministerio de Economía y Competitividad, García Aboal, Rocío, Atienzar Corvillo, Pedro Enrique, Ramiro Manzano, Fernando, Universitat Politècnica de València. Instituto Universitario Mixto de Tecnología Química - Institut Universitari Mixt de Tecnologia Química, Generalitat Valenciana, Agencia Estatal de Investigación, Ministerio de Economía y Competitividad, and García Aboal, Rocío
- Abstract
Tesis por compendio, [ES] La creciente urbanización e industrialización de las sociedades en las últimas décadas han provocado una alta demanda de energía. No obstante, mientras no se desarrollen fuentes de energía renovables que se constituyan como un reemplazo plausible de las actuales, la liberación de gases de efecto invernadero y sus consecuencias sobre el cambio climático difícilmente serán atajadas. Por ello, se está llevando a cabo una intensa búsqueda de energías renovables para un futuro inmediato. En los últimos años, la perovskita ha alcanzado una gran popularidad, centrando numerosos esfuerzos de investigación debido a sus propiedades ópticas y eléctricas únicas. Como por ejemplo su alto coeficiente de absorción y su alta movilidad de carga. Esta tesis comprende seis artículos científicos en torno a las perovskitas. Por un lado, 3 trabajos estudian los fenómenos ópticos que ocurren en el seno del material, con la finalidad de lograr una mejor comprensión de éstos. Puesto que el conocimiento de estos fenómenos ópticos a nivel individual (cristales aislados) permite modular y adaptar su síntesis y morfología para aplicaciones determinadas. Por otro lado, las perovskitas han sido implementadas en distintos dispositivos para su aplicación en tres campos: fotocatálisis, sensores y fotovoltaica. Por primera vez, se ha logrado utilizar este material para la obtención de hidrógeno llevando a cabo la reacción en fase vapor. Asimismo, diversas composiciones de perovskita se han usado para decorar grafeno y detectar niveles traza de Compuestos Orgánicos Volátiles (COV) como benceno y tolueno. Y finalmente se ha desarrollado una estrategia para insertar en la estructura de la perovskita moléculas orgánicas, de forma que se permite una ampliación de la fotorespuesta en el espectro visible. Por lo tanto, las perovskitas se han implementado exitosamente en aplicaciones de diversa índole, constituyéndose como un material prometedor y fácilmente adaptable a los distintos requisitos de cada, [CAT] La creixent urbanització i industrialització de les societats durant les últimes dècades han provocat una alta demanda d'energia. No obstant això, fins que no es desenvolupen fonts d'energia renovables que puguen ser un reemplaçament plausible de les actuals, l'alliberament de gasos d'efecte hivernacle i les seues conseqüències sobre el canvi climàtic seran difícilment aturades. Per tant, s'està duent a terme una intensa cerca d'energies renovables per a un futur immediat. En els últims anys, la perovskita ha aconseguit una gran popularitat, centrant nombrosos esforços de recerca a causa de les seues propietats òptiques i elèctriques úniques. Per exemple, el seu al coeficient d'absorció i la seua alta mobilitat de càrrega. Aquesta tesi reuneix sis articles científics al voltant de les perovskites. Per una banda, 3 treballs estudien els fenòmens òptics que ocorren en el material, amb la finalitat d'assolir una major comprensió d'aquests. Donat que el coneixement d'aquests fenòmens òptics a nivell individual (cristalls aïllats) permeten modular i adaptar la seua síntesi i morfologia per a determinades aplicacions. Per altra banda, les perovskites han sigut implementats en diferents dispositius per a la seua aplicació en tres camps: fotocatàlisi, sensors i fotovoltaica. Per primera vegada, s'hi ha aconseguit utilitzar aquest material per a l'obtenció d'hidrogen duent a terme la reacció en fase vapor. Així mateix, diverses composicions de perovskita s'han utilitzat per a decorar grafè i detectar nivells traça de Compostos Orgànics Volàtils (COV) com benzè i toluè. I finalment s'ha desenvolupat una estratègia per a inserir en l'estructura de la perovskita molècules orgàniques, de forma que es permet una ampliació de la fotoresposta en l'espectre del visible. Per tant, les perovskites s'han implementat exitosament en aplicacions de diversa índole, constituint-se com un material prometedor i fàcilment adaptable als diferents requisits de cada camp d'estudi., [EN] During the last decades, the growing urbanization and industrialization result in a significant need for energy. However, since feasible renewable energy sources should be further developed to replace the current energy source, the release of greenhouse gases and their climate change consequences are difficult to overcome. For that reason, the development of renewable energy sources has been attracting growing research efforts. Recently, perovskites gathered great interest owing to their outstanding optical and electrical properties. For instance, their high absorption coefficient and superior charge mobility. This thesis comprises six scientific articles about perovskites. On one hand, 3 works study the optical phenomena that occur within the material in order to achieve a better understanding. The deep knowledge of these optical phenomena's at the individual level (isolated crystals) enable the modulation and tuning of their synthesis and morphology to match specific applications. On another hand, perovskites have been implemented in several devices for their application in three research fields: photocatalysis, sensors, and photovoltaic. For the first time, this nanomaterial was successfully employed for obtaining hydrogen carrying out the reaction in the vapor phase. Likewise, several perovskite compositions have been used for decorating graphene and detect trace levels of Volatile Organic Compounds (VOC) as benzene and toluene. And finally, it has been developed a strategy to insert organic molecules in the perovskite structure, resulting in an enhanced photoresponse in the visible range. Therefore, perovskites have been successfully implemented in several applications, becoming a promising material and easily adaptable to the different requirements needed in each field of study.
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- 2021
35. Characterization of two coupled photonic crystal nanocavities
- Author
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Universitat Politècnica de Catalunya. Departament de Física, Centre de Nanosciences et de Nanotechnologies (C2N), Giacomotti, Alejandro, Cojocaru, Crina, Paris Escarcelle, David, Universitat Politècnica de Catalunya. Departament de Física, Centre de Nanosciences et de Nanotechnologies (C2N), Giacomotti, Alejandro, Cojocaru, Crina, and Paris Escarcelle, David
- Abstract
Nanolasers are a fundamental piece of all-optical integrated circuits and their several applications. In this work, the nanolaser is a system of two coupled nanocavities in a semiconductor photonic crystal, characterized by a high Qfactor, tunable coupling, a nonlinear quantum well gain medium, and improved beaming. A theoretical introduction including the physical basis of the system and the sample description is provided. Also, the experimental set-up and the measurement methodology are described. ASThe system is firstly characterized under the optical pump regime, in which laser regime phenomena like before-threshold wavelength blueshift are observed. The coupled system exhibits a hybridization between bonding and antibonding modes, altered by system properties like coupling or detuning between cavities. Mode competition and mode reversing are also observed for several situations. ASFurthermore, the system is taken as two coupled resonators and coherently injected. The transmitted linear resonances are recorded for different parameters, observing mode hybridization, mode extinction, and mode reversing around zero couplings. Moreover, the phenomenon of avoided mode crossing is firstly observed in a system of photonic crystal nanocavities., Los nanoláseres son una pieza fundamental de los circuitos integrados totalmente ópticos y su varias aplicaciones. En este trabajo, el nanolaser es un sistema de dos acoplados nanocavidades en un cristal fotónico semiconductor, caracterizado por un factor Q alto, un acoplamiento sintonizable, un medio de ganancia de pozo cuántico no lineal y una mejora radiante. Una introducción teórica que incluye la base física del sistema. y se proporciona la descripción de muestra. Además, de la configuración experimental se describe la metodología de medición. AS El sistema se caracteriza en primer lugar bajo el régimen de bombeo óptico, en el que se observan fenómenos del régimen del láser como el desplazamiento al azul de la longitud de onda antes del umbral. El sistema acoplado exhibe una hibridación entre unión y antienlazamiento. Modos, alterados por propiedades del sistema como acoplamiento o desafinación entre cavidades. La competencia de modo y la inversión de modo, también se observan en varias situaciones. AS Además, el sistema se toma como dos resonadores acoplados y se inyecta coherentemente. Las resonancias lineales transmitidas se registran para diferentes parámetros: modo de observación, de hibridación, modo de extinción,e inversión de modo alrededor de acoplamientos cero. Además, el fenómeno del cruce de modos evitado se observa en primer lugar en un sistema de nanocavidades de cristales fotónicos., Els nanolasers són una peça fonamental de circuits òptics integrats i les seves diverses aplicacions. En aquest treball, el nanolaser és un sistema de dos nanocavitats d'un cristall fotònic semiconductor, caracteritzat per un elevat factor de qualitat, un acoblament modificable, un medi actiu no lineal amb pous quàntic mitjà i un "beaming" millorat. Es proporciona una introducció teòrica que inclou la base física del sistema i també la descripció de la mostra. A més, es descriu la configuració experimental i la metodologia de mesura. El sistema es caracteritza primer pel règim de pompatge òptic, en el qual s'observen fenòmens de règim làser com el desplaçament blau de longitud d'ona abans del llindar làser. El sistema acoblat presenta una hibridació entre modes, alterats per propietats del sistema com l'acoblament o desafinació entre cavitats. La competència i inversió entre modes també es caracteritzen per diverses situacions. A més, el sistema es pren com a dos ressonadors acoblats i s'injecta de manera coherent. Les ressonàncies lineals transmeses es registren per diferents paràmetres, observant la hibridació dels modes, l'extinció dels modes i la inversió dels modes al voltant de zero acoblaments. A més, el fenomen del creuament de modes evitat s'observa en primer lloc en un sistema de nanocavitats de cristalls fotònics.
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- 2021
36. Microscopio invertido con luz estructurada mediante DMD
- Author
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Ordóñez Angamarca, Luis, Ipus Bados, Erick Fabian, Lenz, Armin Johannes Maxemilian, Martí Sabaté, Marc, Tajahuerce Romera, Enrique, Ordóñez Angamarca, Luis, Ipus Bados, Erick Fabian, Lenz, Armin Johannes Maxemilian, Martí Sabaté, Marc, and Tajahuerce Romera, Enrique
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- 2021
37. Engineering analog quantum chemistry Hamiltonians using cold atoms in optical lattices
- Author
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Argüello Luengo, Javier, Shi, Tao, González Tudela, Alejandro, Argüello Luengo, Javier, Shi, Tao, and González Tudela, Alejandro
- Abstract
Using quantum systems to efficiently solve quantum chemistry problems is one of the long-sought applications of near-future quantum technologies. In a recent work [J. Argüello-Luengo et al., Nature (London) 574, 215 (2019)], ultracold fermionic atoms have been proposed for this purpose by showing us how to simulate in an analog way the quantum chemistry Hamiltonian projected in a lattice basis set. Here, we continue exploring this path and go beyond these results in several ways. First, we numerically benchmark the working conditions of the analog simulator and find less demanding experimental setups where chemistry-like behavior in three dimensions can still be observed. We also provide a deeper understanding of the errors of the simulation appearing due to discretization and finite-size effects and provide a way to mitigate them. Finally, we benchmark the simulator characterizing the behavior of two-electron atoms (He) and molecules ( HeH + ) beyond the example considered in the original work., The authors acknowledge very insightful discussions and feedback from J. I. Cirac and P. Zoller, with whom they worked in the original proposal of Ref. [1]. J.A.-L. acknowledges support from ’la Caixa’ Foundation (ID 100010434) through the fellowship LCF/BQ/ES18/11670016, the Spanish Ministry of Economy and Competitiveness through the ’Severo Ochoa’ program (CEX2019-000910-S), Fundació Privada Cellex, Fundació Mir-Puig, and Generalitat de Catalunya through the CERCA program and QuantumCat (001-P-001644). T. S. acknowledges the support from NSFC 11974363. A. G.-T. acknowledges support from the Spanish project PGC2018-094792-B-100 (MCIU/AEI/FEDER, EU) and from the CSIC Research Platform on Quantum Technologies PTI-001., Peer Reviewed, Postprint (author's final draft)
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- 2021
38. Towards the bisbenzothienocarbazole core: a route of sulfurated carbazole derivatives with assorted optoelectronic properties and applications
- Author
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Universitat Politècnica de Catalunya. Departament d'Enginyeria Electrònica, Universitat Politècnica de Catalunya. MNT - Grup de Recerca en Micro i Nanotecnologies, Bujaldón Carbó, Roger, Puigdollers i González, Joaquim, Velasco Castrillo, Maria Dolores, Universitat Politècnica de Catalunya. Departament d'Enginyeria Electrònica, Universitat Politècnica de Catalunya. MNT - Grup de Recerca en Micro i Nanotecnologies, Bujaldón Carbó, Roger, Puigdollers i González, Joaquim, and Velasco Castrillo, Maria Dolores
- Abstract
Ladder-type molecules, which possess an extended aromatic backbone, are particularly sought within the optoelectronic field. In view of the potential of the 14H-bis[1]benzothieno[3,2-b:2’,3’-h]carbazole core as a p-type semiconductor, herein we studied a set of two derivatives featuring a different alkylation patterning. The followed synthetic route, involving various sulfurated carbazole-based molecules, also resulted in a source of fluorophores with different emitting behaviors. Surprisingly, the sulfoxide-containing fluorophores substantially increased their blue fluorescence with respect to the nearly non-emitting sulfur counterparts. On this basis, we could shed light on the relationship between their chemical structure and their emission as an approach for future applications. Considering the performance in organic thin-film transistors, both bisbenzothienocarbazole derivatives displayed p-type characteristics, with hole mobility values up to 1.1 × 10-3 cm2 V-1 s-1 and considerable air stability. Moreover, the role of the structural design has been correlated with the device performance by means of X-ray analysis and the elucidation of the corresponding single crystal structures., This research was funded by the Ministerio de Economía, Indústria y Competitividad, grant number FUNMAT-PGC2018-095477-B-I00, and the Ministerio de Ciencia e Innovación, grant number PID2020-116719RB-C41., Peer Reviewed, Postprint (published version)
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- 2021
39. Exciton diffusion in two-dimensional metal-halide Perovskites
- Author
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Seitz, Michael, Prins, Ferry, Norbert Congreve, Daniel, and UAM. Departamento de Física de la Materia Condensada
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Excitones ,Perovskitas ,Física ,Optoelectrónica - Abstract
Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física de la Materia Condensada. Fecha de lectura: 08-07-2021, Metal-halide perovskites have emerged as a promising material platform in many optoelectronic applications such as light harvesting and light emitting applications. Perovskites offer a unique combination of outstanding properties, however, conventional 3D perovskites suffer from rapid degradation when exposed to ambient conditions. Two-dimensional (2D) perovskites, on the other hand, have been shown to have a superior chemical stability and have proven to be one of the most promising strategies to yield a more stable performance. However, the reduced dimensionality of 2D perovskites dramatically affects the charge carrier dynamics in these materials as excitons - electron-hole pairs - become the dominant energy carriers rather than free charges. While there has been an extensive amount of research to understand the charge carrier dynamics in 3D perovskites, our knowledge about the exciton dynamics in 2D perovskites is still limited. This thesis strives to close part of this knowledge gap by studying the transport properties of various 2D perovskites. We will discuss the influence of organic-spacer molecules and find that transport is most likely limited due to strong exciton-phonon interactions. Further, we investigate the effect of halide alloying - the most commonly used strategy to change the color of the perovskite materials in, for example, LEDs. Surprisingly, we find that halide alloying can diminish exciton transport and therefore has to be considered for device design. Finally, the impact of trap-states on exciton diffusion will be thoroughly studied.We will provide models to describe trap state-limited exciton transport and show that transient microscopy can be used as an orthogonal method to more conventional optical characterization techniques. The results in this thesis are primarily derived from transient optical microscopy and spectroscopy measurements, and rigorous modeling of exciton transport by solving the diffusion equation and performing Brownian dynamics simulations
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- 2021
40. Caracterización de dos nanocavidades acopladas de cristal fotónico
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Paris Escarcelle, David, Universitat Politècnica de Catalunya. Departament de Física, Centre de Nanosciences et de Nanotechnologies (C2N), Giacomotti, Alejandro, and Cojocaru, Crina
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pump óptico ,Quantum optics ,nanocavities ,Fotònica ,resonant injection ,nanolaser ,optical pump ,Òptica quàntica ,Photonics ,Enginyeria de la telecomunicació::Telecomunicació òptica::Fotònica [Àrees temàtiques de la UPC] ,Optoelectronics ,Cristal fotónico ,nanocavidades ,Optoelectrònica ,Photonic Crystal ,inyección resonante - Abstract
Nanolasers are a fundamental piece of all-optical integrated circuits and their several applications. In this work, the nanolaser is a system of two coupled nanocavities in a semiconductor photonic crystal, characterized by a high Qfactor, tunable coupling, a nonlinear quantum well gain medium, and improved beaming. A theoretical introduction including the physical basis of the system and the sample description is provided. Also, the experimental set-up and the measurement methodology are described. ASThe system is firstly characterized under the optical pump regime, in which laser regime phenomena like before-threshold wavelength blueshift are observed. The coupled system exhibits a hybridization between bonding and antibonding modes, altered by system properties like coupling or detuning between cavities. Mode competition and mode reversing are also observed for several situations. ASFurthermore, the system is taken as two coupled resonators and coherently injected. The transmitted linear resonances are recorded for different parameters, observing mode hybridization, mode extinction, and mode reversing around zero couplings. Moreover, the phenomenon of avoided mode crossing is firstly observed in a system of photonic crystal nanocavities. Los nanoláseres son una pieza fundamental de los circuitos integrados totalmente ópticos y su varias aplicaciones. En este trabajo, el nanolaser es un sistema de dos acoplados nanocavidades en un cristal fotónico semiconductor, caracterizado por un factor Q alto, un acoplamiento sintonizable, un medio de ganancia de pozo cuántico no lineal y una mejora radiante. Una introducción teórica que incluye la base física del sistema. y se proporciona la descripción de muestra. Además, de la configuración experimental se describe la metodología de medición. AS El sistema se caracteriza en primer lugar bajo el régimen de bombeo óptico, en el que se observan fenómenos del régimen del láser como el desplazamiento al azul de la longitud de onda antes del umbral. El sistema acoplado exhibe una hibridación entre unión y antienlazamiento. Modos, alterados por propiedades del sistema como acoplamiento o desafinación entre cavidades. La competencia de modo y la inversión de modo, también se observan en varias situaciones. AS Además, el sistema se toma como dos resonadores acoplados y se inyecta coherentemente. Las resonancias lineales transmitidas se registran para diferentes parámetros: modo de observación, de hibridación, modo de extinción,e inversión de modo alrededor de acoplamientos cero. Además, el fenómeno del cruce de modos evitado se observa en primer lugar en un sistema de nanocavidades de cristales fotónicos. Els nanolasers són una peça fonamental de circuits òptics integrats i les seves diverses aplicacions. En aquest treball, el nanolaser és un sistema de dos nanocavitats d'un cristall fotònic semiconductor, caracteritzat per un elevat factor de qualitat, un acoblament modificable, un medi actiu no lineal amb pous quàntic mitjà i un "beaming" millorat. Es proporciona una introducció teòrica que inclou la base física del sistema i també la descripció de la mostra. A més, es descriu la configuració experimental i la metodologia de mesura. El sistema es caracteritza primer pel règim de pompatge òptic, en el qual s'observen fenòmens de règim làser com el desplaçament blau de longitud d'ona abans del llindar làser. El sistema acoblat presenta una hibridació entre modes, alterats per propietats del sistema com l'acoblament o desafinació entre cavitats. La competència i inversió entre modes també es caracteritzen per diverses situacions. A més, el sistema es pren com a dos ressonadors acoblats i s'injecta de manera coherent. Les ressonàncies lineals transmeses es registren per diferents paràmetres, observant la hibridació dels modes, l'extinció dels modes i la inversió dels modes al voltant de zero acoblaments. A més, el fenomen del creuament de modes evitat s'observa en primer lloc en un sistema de nanocavitats de cristalls fotònics.
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- 2021
41. Engineering analog quantum chemistry Hamiltonians using cold atoms in optical lattices
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Javier Argüello-Luengo, Alejandro González-Tudela, Tao Shi, Fundación Caixa Galicia, Ministerio de Economía y Competitividad (España), Fundació Privada Cellex, Fundación Privada Mir-Puig, Generalitat de Catalunya, National Science Foundation (US), Agencia Estatal de Investigación (España), and Consejo Superior de Investigaciones Científicas (España)
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Discretization ,FOS: Physical sciences ,01 natural sciences ,Quantum chemistry ,010305 fluids & plasmas ,symbols.namesake ,Theoretical physics ,0103 physical sciences ,Molecule ,Química quàntica ,010306 general physics ,Quantum ,Simulació, Mètodes de ,Physics ,Quantum Physics ,Física [Àrees temàtiques de la UPC] ,Quantum technology ,Simulation methods ,Optical lattices ,Quantum Gases (cond-mat.quant-gas) ,symbols ,Hamiltonian (quantum mechanics) ,Condensed Matter - Quantum Gases ,Optoelectrònica ,Quantum Physics (quant-ph) ,Lattice basis - Abstract
25 pags., 14 figs., 3 apps., Using quantum systems to efficiently solve quantum chemistry problems is one of the long-sought applications of near-future quantum technologies. In a recent work [J. Argüello-Luengo, Nature (London) 574, 215 (2019)NATUAS0028-083610.1038/s41586-019-1614-4], ultracold fermionic atoms have been proposed for this purpose by showing us how to simulate in an analog way the quantum chemistry Hamiltonian projected in a lattice basis set. Here, we continue exploring this path and go beyond these results in several ways. First, we numerically benchmark the working conditions of the analog simulator and find less demanding experimental setups where chemistry-like behavior in three dimensions can still be observed. We also provide a deeper understanding of the errors of the simulation appearing due to discretization and finite-size effects and provide a way to mitigate them. Finally, we benchmark the simulator characterizing the behavior of two-electron atoms (He) and molecules (HeH+) beyond the example considered in the original work., J.A.-L. acknowledges support from “la Caixa” Foundation (Grant No. 100010434) through the fellowship LCF/BQ/ES18/11670016, the Spanish Ministry of Economy and Competitiveness through the “Severo Ochoa” program (Grant No. CEX2019-000910-S), Fundació Privada Cellex, Fundació Mir-Puig, and Generalitat de Catalunya through the CERCA program and QuantumCat (Grant No. 001-P-001644). T.S. acknowledges the support from NSFC Grant No. 11974363. A.G.-T. acknowledges support from the Spanish Project No. PGC2018-094792-B-100 (MCIU/AEI/FEDER, EU) and from the CSIC Research Platform on Quantum Technologies No. PTI-001.
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- 2021
42. Espesores críticos de relajación en pozos cuánticos de InGaAs/ GaAs sobre sustratos de GaAs (001) y (111)B
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Gutiérrez, M., González, D., Aragón, G., Sánchez, J. J., Izpura, I., and García, R.
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Critical thickness ,(111)B GaAs ,relaxation ,optoelectronics ,Espesor crítico ,relajación ,optoelectrónica ,Clay industries. Ceramics. Glass ,TP785-869 - Abstract
A study of critical layer thickness (CLT) in single quantum wells of InGaAs/GaAs on GaAs substrates with (001) and (111)B orientations is presented. The results obtained by Transmission Electronic Microscopy (TEM) and Photoluminescence (PL) show that the decrease of the luminescent signal is due to different relaxation mechanisms for each substrate orientation. Thus, in (001) substrates, the CLT is defined by the transition from a plane growth front (2D) to a rough one (3D). However, the plastic relaxation due to a misfit dislocation array (DD) determines the CLT in (111)B substrates. The analysis by TEM of this dislocation array shows a new DD configuration different to the previously described in the bibliography. The new observed configuration allows us to explain the experimental results obtained for the case of SQW of InGaAs/GaAs (111)B using the classic CLT models of the first DD formation.Se presenta un estudio mediante Microscopía Electrónica de Transmisión (TEM) y Fotoluminiscencia (PL) de espesores críticos de epicapa (CLT) en pozos cuánticos simples de InGaAs/GaAs crecidos sobre substratos de GaAs con orientaciones (001) y (111)B. Los resultados obtenidos demuestran que la disminución de la señal luminiscente del espectro de PL se debe a distintos mecanismos de relajación para cada orientación de sustrato. Así, en sustratos orientados (001), el CLT viene definido por la transición desde un frente de crecimiento plano (2D) a otro ondulado (3D). Sin embargo, la relajación plástica debida a una red de dislocaciones de desajuste (DD) determina el CLT en sustratos orientados (111)B. El análisis por TEM de esta red de dislocaciones muestra la existencia de una nueva configuración de DD distinta a la anteriormente descrita en la bibliografía. La nueva configuración observada permite explicar los resultados experimentales obtenidos para el caso de SQW de InGaAs/ GaAs (111)B utilizando los modelos clásicos de CLT de formación de la primera DD.
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- 2000
43. Sistemas polimetálicos con propiedades optoelectrónicas, mesomórficas y de conductividad
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Conejo Rodríguez, Verónica, Espinet Rubio, Pablo, Universidad de Valladolid. Facultad de Ciencias, Conejo Rodríguez, Verónica, Espinet Rubio, Pablo, and Universidad de Valladolid. Facultad de Ciencias
- Abstract
La investigación comprende el diseño de nuevos compuestos con propiedades optoelectrónicas, mesomórficas y de conductividad con un alto potencial para su uso como materiales avanzados. El principal objetivo de esta investigación es la preparación de nuevos materiales mediante la obtención de sistemas metalo-orgánicos con átomos metálicos iguales o diferentes y autorganización de moléculas en estructuras más complejas, que vean reforzadas o modificadas determinadas propiedades en función del fragmento organometálico, sea en su estado cristalino, en mesofase, o en disolución. Para llevar a cabo dicho objetivo se han utilizado ligandos de diferente naturaleza, funcionalizados con determinados fragmentos orgánicos (pro)mesógenos (diaza-éteres corona derivatizados, piridilisocianuros, arilisocianuros e isocianotrifenilenos), e incorporarados a centros metálicos de una manera selectiva (AuI, AuIII, AgI y RhI); y así, construir agregados polimetálicos (homo o heterometálicos) cristalinos o mesomórficos, con propiedades derivadas de los diferentes tipos de interacciones y el estudio de las mismas., Departamento de Química Física y Química Inorgánica, Doctorado en Química: Química de Síntesis, Catálisis y Materiales Avanzados
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- 2020
44. Quantum simulation of two-dimensional quantum chemistry in optical lattices
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Argüello Luengo, Javier, González Tudela, Alejandro, Shi, Tao, Zoller, Peter, Cirac Sasturain, Juan Ignacio, Argüello Luengo, Javier, González Tudela, Alejandro, Shi, Tao, Zoller, Peter, and Cirac Sasturain, Juan Ignacio
- Abstract
Benchmarking numerical methods in quantum chemistry is one of the key opportunities that quantum simulators can offer. Here, we propose an analog simulator for discrete two-dimensional quantum chemistry models based on cold atoms in optical lattices. We first analyze how to simulate simple models, such as the discrete versions of H and H + 2 , using a single fermionic atom. We then show that a single bosonic atom can mediate an effective Coulomb repulsion between two fermions, leading to the analog of molecular hydrogen in two dimensions. We extend this approach to larger systems by introducing as many mediating atoms as fermions, and derive the effective repulsion law. In all cases, we analyze how the continuous limit is approached for increasing optical lattice sizes., We acknowledge support from the ERC Advanced Grant QUENOCOBA under the EU Horizon 2020 program (Grant Agreement No. 742102). J.A.-L. acknowledges support from “la Caixa” Foundation (ID 100010434) through the fellowship No. LCF/BQ/ES18/11670016, the Spanish Ministry of Economy and Competitiveness through the “Severo Ochoa” program (SEV-2015-0522), Fundació Privada Cellex, Fundació Mir-Puig, and Generalitat de Catalunya through the CERCA program. A.G.-T. acknowledges support from the Spanish project No. PGC2018-094792-B-100 (MCIU/aEI/FEDER, EU) and from the CSIC Research Platform on Quantum Technologies PTI-001. T.S. acknowledges the Thousand-Youth-Talent Program of China and is supported by the NSFC No. 11974363. P.Z. acknowledges the EU Quantum Flagship PASQuanS., Peer Reviewed, Postprint (published version)
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- 2020
45. Over 10% efficient wide bandgap CIGSe solar cells on transparent substrate with Na predeposition treatment
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Universitat Politècnica de Catalunya. Departament d'Enginyeria Electrònica, Placidi, Marcel Jose, Saucedo Silva, Edgardo Ademar, Jehl, Zacharie Victor Samuel Na, Universitat Politècnica de Catalunya. Departament d'Enginyeria Electrònica, Placidi, Marcel Jose, Saucedo Silva, Edgardo Ademar, and Jehl, Zacharie Victor Samuel Na
- Abstract
With the recent rise of new photovoltaic applications, it has become necessary to develop specific optoelectronic properties for thin-film technologies such as Cu(In,Ga)Se2 and to take advantage of their high degree of tunability. The feasibility of efficient wide bandgap absorbers on transparent conductive oxide substrates is, in that context, of critical importance. Using an original approach based on a predeposition sodium treatment, Cu(In,Ga)Se2 absorbers fabricated by sputtering and reactive annealing with a Ga to (Ga + In) content over 0.7 and an optical bandgap above 1.4 eV are deposited on transparent fluorine-doped tin oxide films, with the insertion of an ultrathin MoSe2 layer preserving the contact's ohmicity. Different material characterizations are carried out, and a thorough Raman analysis of the absorber reveals that the sodium pretreatment significantly enhances the Ga incorporation into the chalcopyrite matrix, along with markedly improving the film's morphology and crystalline quality. This translates to a spectacular boost of the photovoltaic performance for the resulting solar cell as compared with a reference device without Na, specifically in the voltage and fill factor. Eventually, an efficiency exceeding 10% is obtained without antireflection coating, a record value bridging the gap with the state of the art on nontransparent substrates., Peer Reviewed, Postprint (author's final draft)
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- 2020
46. Interferometric lens-free microscopy of structured materials
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Universitat Politècnica de Catalunya. Institut de Ciències Fotòniques, Pruneri, Valerio, Hägele, Sebastian, Universitat Politècnica de Catalunya. Institut de Ciències Fotòniques, Pruneri, Valerio, and Hägele, Sebastian
- Abstract
The lens-free interferometric microscope (?LIM?) developed at ICFO by Roland Terborg et al. offers a hybrid solution of differential interference contrast microscopy, interferometry and holography. It is an ultra-sensitive interferometric microscope used for the analysis of structures and defects on the surface or inside the bulk of transparent materials, that can be both in transmission and reflection. It is an evolving platform, both from a hardware and software perspective. One of the main tasks in this thesis was to add an image processing algorithm to the LIM platform that can be used to detect, mark and analyse optical phase features on or inside transparent samples. The segmentation algorithm, based on edge detection, watershed transform and K-means classification, is used to classify phase maps into background and feature. Once classified into a binary map, connected areas are assigned to an integer label and the properties of the underlying phase map are measured. This allows to perform a systematic quantitative and statistical analysis of phase features by discarding the information that is out of focus. When samples containing features of known size are measured, the algorithm can be tailored for a detailed analysis of these feature structures, not only in 2D but also in 3D. The segmentation and labelling algorithm is augmented into a labelling based autofocus, that is capable of finding features planes or layers with known geometric features. Several tests are performed to prove the capabilities of the segmentation and labelling algorithm both in 2D and 3D, in combination with the proposed autofocus. Part of this is an analysis of embedded refractive index structures inside a 1 mm thick glass slide. The structures are completely invisible to the human eye and other microscopes. The smallest features are 50 by 50 µm in size and induce an optical distortion equivalent to 10 nm on the wavefront of transmitted light. The LIM is capable of making them visible
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- 2020
47. Deep-sea deployment of the KM3NeT neutrino telescope detection units by self-unrolling
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Centre Tecnològic de Vilanova i la Geltrú, Universitat Politècnica de Catalunya. LAB - Laboratori d'Aplicacions Bioacústiques, Aiello, S, Albert, Andreas, Alves Garre, Sergio, Ameli, F, Anassontzis, E.G., André, Michel, Androulakis, Giorgos, Anghinolfi, Marco, Anguita, M., Anton, Gisela, Ardid Ramírez, Miguel, Aublin, J., Bagatelas, Christos, Centre Tecnològic de Vilanova i la Geltrú, Universitat Politècnica de Catalunya. LAB - Laboratori d'Aplicacions Bioacústiques, Aiello, S, Albert, Andreas, Alves Garre, Sergio, Ameli, F, Anassontzis, E.G., André, Michel, Androulakis, Giorgos, Anghinolfi, Marco, Anguita, M., Anton, Gisela, Ardid Ramírez, Miguel, Aublin, J., and Bagatelas, Christos
- Abstract
KM3NeT is a research infrastructure being installed in the deep Mediterranean Sea. It will house a neutrino telescope comprising hundreds of networked moorings—detection units or strings—equipped with optical instrumentation to detect the Cherenkov radiation generated by charged particles from neutrino-induced collisions in its vicinity. In comparison to moorings typically used for oceanography, several key features of the KM3NeT string are different: the instrumentation is contained in transparent and thus unprotected glass spheres; two thin Dyneema\textsuperscript{\textregistered} ropes are used as strength members; and a thin delicate backbone tube with fibre-optics and copper wires for data and power transmission, respectively, runs along the full length of the mooring. Also, compared to other neutrino telescopes such as ANTARES in the Mediterranean Sea and GVD in Lake Baikal, the KM3NeT strings are more slender to minimise the amount of material used for support of the optical sensors. Moreover, the rate of deploying a large number of strings in a period of a few years is unprecedented. For all these reasons, for the installation of the KM3NeT strings, a custom-made, fast deployment method was designed. Despite the length of several hundreds of metres, the slim design of the string allows it to be compacted into a small, re-usable spherical launching vehicle instead of deploying the mooring weight down from a surface vessel. After being lowered to the seafloor, the string unfurls to its full length with the buoyant launching vehicle rolling along the two ropes. The design of the vehicle, the loading with a string, and its underwater self-unrolling are detailed in this paper., Peer Reviewed, Postprint (published version)
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- 2020
48. Two-dimensional III via semiconductors and their applications in optoelectronic devices
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Castellanos-Gómez, Andrés, Frisenda, Riccardo, Agrait de la Puente, Nicolás, China Scholarship Council, Zhao, Qinghua, Castellanos-Gómez, Andrés, Frisenda, Riccardo, Agrait de la Puente, Nicolás, China Scholarship Council, and Zhao, Qinghua
- Abstract
Two-dimensional (2D) semiconductors, initialed by the isolation of graphene in 2004, have drawn a great research interest thanks to their remarkable mechanical, electrical, optical, and optoelectronic properties. Their layered structure, originating from the strong in-plane covalent bonds and weak out-of-plane van der Waals interactions, allows such materials being stable with atomically thin geometry. Thanks to the ultrathin nature and dangling-bond-free surface, various advanced heterostructures-based devices with superior performance have been demonstrated without being hampered by their lattice mismatch, which make them as promising candidates for future nano-electronic and optoelectronic applications. As novel 2D members from III – VIA semiconducting group, Gallium selenide (GaSe) and Indium selenide (InSe), are barely explored but recently both reach exciting promise in theory achievements and application research. Thanks to their unique electron band structures and strong light-matter interactions, they both are sensitive to external stimuli, which can be advantageous for certain applications but also brings drawbacks for others, thus motivates the goal of this thesis that exploring how the environment, light and strain play roles on the properties of these materials. Two dimensional materials are especially sensitive to the environmental atmosphere and to external stimuli due to their layered structures and large surface-to-volume ratio. Thus, in the first part of this thesis, the interaction between air species and thin GaSe and InSe flakes has been discussed. Thin GaSe can be degraded completely after being exposed in the air for several days, during which macro- and micro-scope surface morphology evolution, chemical composition variation, and laser-induced degradation, as well as how it leads to the photodetector breakdown as a function of exposure time in air have been fully presented. On the contrary, thin InSe shows a different environmental interactio, Thanks to the dangling-bond-free surface of 2D semiconductors and the deterministic transfer methods, one can fabricate pure van der Waals (vdW) metal-semiconductor interfaces, without direct chemical covalent bonding that typically leads to chemical disorder and Fermi-level pinning (FLP). This kind of vdW metal-semiconductor is thus an ideal system to study the Schottky junctions. The defects passivation effect in InSe introduced by air species not only can modify the material properties but also reduces the fermi level pinning at the metal-InSe contact interface. Various Schottky contact based on thin InSe with different van der Waals electrical contacts have been investigated. The Schottky barrier height at the interfaces of Au-InSe, Pt-InSe and InSe-Gr (graphite) are determined to be approximately 460 meV, 540 meV and less than 100 meV, respectively. Taking advantage of the large contact barrier difference, the transport properties of Schottky diodes based on engineered asymmetric van der Waals contacts of thin InSe, including Au-InSe-Gr and Pt-InSe-Gr, have been investigated. The dangling-bond-free nature of the surface of 2D materials leads to high mechanical resilience against mechanical deformation. This has motivated a whole sub-field of research focused on using mechanical deformation to tune the electronic properties of 2D materials. The mechanical properties of GaSe and InSe were barely explored at the moment of the elaboration of this thesis and thus to decide to measure the Young’s modulus of InSe to access its suitability in strain engineering applications. Using buckling metrology method, the Young’s modulus of InSe is experimentally determined to be 23 ± 5 GPa, which makes thin InSe one of the most flexible 2D materials. Subsequently, the biaxial strain tunability of thin InSe, including piezoresistance effect, band gap modulation, and strain engineered optoelectronic devices has been discussed. Interestingly, it is further demonstrated that how the
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- 2020
49. Straintronic photodetectors based on 2D materials
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Castellanos-Gómez, Andrés, Frisenda, Riccardo, Agrait de la Puente, Nicolás, Gant, Patricia, Castellanos-Gómez, Andrés, Frisenda, Riccardo, Agrait de la Puente, Nicolás, and Gant, Patricia
- Abstract
[EN] The world suffered an enormous revolution thanks to the emergence of the electronics; nowadays, our lives are surrounded by electronic devices that make them easier. Since the first fabrication of a transistor (the base the most common electronic devices) in 1947, electronics is been improving its performance by adding more elements to the electronic devices. In order to maintain the level of improvement, the size of the components included in the electronic devices decreased, which have led to difficulties during the last years. Researchers are looking for different strategies to continue the enhancement of electronics, among which is the study of new materials like 2D semiconductors. Likewise, another proposed idea is including more tuning knobs in the components, which would increase the functionality of each component. The different options for increasing the responses of the components include the control of different properties (degrees of freedom) of the device through control the valey or spin polarization or applying external deformations leading to valleytronics, spintronics, straintronics respectively. The main aim of this thesis is the development of a proof-of-concept straintronic device, which would proof the viability of this technique to keep the electronic progress. Thus, this device is fabricated with a new semiconductor, which allows us to fabricate this type of device unlike silicon (Si). This new material is a 2D semiconductor from the transition metal dichalcogenides (TMDCs) family, MoS2. Due to the special characteristics of 2D materials, the techniques used for studying and manipulating them are different from the common methods used in 3D semiconductor industry. So, we introduce the optical techniques that allow us to characterize the optical properties of these materials. Some of them, like Raman and photoluminescence spectroscopies, are well spread in the material science world while some others are used specifically in 2D materials., [ES] El mundo sufrió una gran revolución cuando la electrónica hizo su aparición; hoy en día, nuestras vidas están rodeadas de dispositivos electrónicos, los cuáles las hacen más fáciles. Desde la fabricación del primer transistor (la base de todos los dispositivos electrónicos) en 1947, la electrónica ha continuado mejorando su rendimiento mediante la agregación de más componentes en los dispositivos electrónicos. Para ser capaces de seguir con la optimización y aumento de componentes, el tamaño de estos disminuyó, lo que ha venido provocando dificultades durante los últimos años. Los investigadores están buscando diferentes estrategias para continuar con la mejora de los dispositivos electrónicos, entre los cuales se encuentran el estudio de nuevos materiales como los semiconductores 2D. Asimismo, otra idea propuesta para mejorar estos dispositivos es incluir más funcionalidades en los componentes, lo que aumentará las respuestas de cada uno de ellos. Las diferentes opciones que permitirían variar y aumentar el número de respuestas de los componentes incluyen el control de diferentes propiedades del dispositivo a través de la valetrónica, espintrónica o deformatrónica. El objetivo principal de esta tesis es el desarrollo de un ejemplo de dispositivo deformatrónico, que demostrará la viabilidad de esta técnica para mantener el progreso electrónico. Así, este dispositivo se fabricará con un nuevo semiconductor, el cual nos permite conseguir este tipo de dispositivo a diferencia del silicio (Si). Este nuevo material es un semiconductor 2D de la familia de los dicalcogenuros de metales de transición (TMDCs), el MoS2. Debido a las características especiales de los materiales 2D, las técnicas utilizadas para estudiarlos y manipularlos son diferentes de los métodos comúnmente utilizados en la industria de semiconductores 3D. Por lo tanto, es necesario que presentemos las técnicas ópticas que nos permiten caracterizar las propiedades ópticas de estos materiales. Algunas d
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- 2020
50. Influence of co-sputtered Ag:Al ultra-thin layers in transparent V2O5/Ag:Al/AZO hole-selective electrodes for silicon solar cells
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Universitat Politècnica de Catalunya. Departament d'Enginyeria Electrònica, Universitat Politècnica de Catalunya. MNT - Grup de Recerca en Micro i Nanotecnologies, Tom, Thomas, Ros Costals, Eloi, Asensi López, José Miguel, Andreu Batallé, Jordi, Bertomeu Balagueró, Joan, Puigdollers i González, Joaquim, Voz Sánchez, Cristóbal, López-Pintó, Nicolau, Universitat Politècnica de Catalunya. Departament d'Enginyeria Electrònica, Universitat Politècnica de Catalunya. MNT - Grup de Recerca en Micro i Nanotecnologies, Tom, Thomas, Ros Costals, Eloi, Asensi López, José Miguel, Andreu Batallé, Jordi, Bertomeu Balagueró, Joan, Puigdollers i González, Joaquim, Voz Sánchez, Cristóbal, and López-Pintó, Nicolau
- Abstract
As optoelectronic devices continue to improve, control over film thickness has become crucial, especially in applications that require ultra-thin films. A variety of undesired effects may arise depending on the specific growth mechanism of each material, for instance a percolation threshold thickness is present in Volmer-Webber growth of materials such as silver. In this paper, we explore the introduction of aluminum in silver films as a mechanism to grow ultrathin metallic films of high transparency and low sheet resistance, suitable for many optoelectronic applications. Furthermore, we implemented such ultra-thin metallic films in Dielectric/Metal/Dielectric (DMD) structures based on Aluminum-doped Zinc Oxide (AZO) as the dielectric with an ultra-thin silver aluminum (Ag:Al) metallic interlayer. The multilayer structures were deposited by magnetron sputtering, which offers an industrial advantage and superior reliability over thermally evaporated DMDs. Finally, we tested the optimized DMD structures as a front contact for n-type silicon solar cells by introducing a hole-selective vanadium pentoxide (V2O5) dielectric layer., This research has been supported by the Spanish Ministerio de Economía, Industria y Competitividad and the European Regional Development Fund through the projects ENE2016-78933-C4-1-R, ENE2016-78933-C4-2-R, PID2019-109215RB-C41, PID2019-1092215RB-C43 and ENE2017-87671-C3-2-R. We acknowledge support of Secretaria d’Universitats i Recerca de la Generalitat de Catalunya and European Social Fund (2019 FI_B 00456)., Peer Reviewed, Postprint (published version)
- Published
- 2020
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