Light propagation in multilayered nanostructures : Characterization and modelling of morphological effects on the optical properties of stratified media
Supervisor(es): Valente, Paulo - Pereyra, Carlos Javier
Resumen:
Nanostructured materials, those with at least one physical dimension of the order of 100 nm or less, have driven significant technological advancements in the last decades. Their ability to manipulate light-matter interactions at this scale, enabling control below the wavelength, has propelled photonics into on of the leading research fields. While natural nanostructured optical materials abound, it was not until the recent development of synthesis techniques that allowed custom fabrication. Among the nanoscale materials, multilayered nanostructures, with thickness confined to the nanoscale, have emerged as a key element in fundamental technologies such as photovoltaic devices for clean energy generation. Understanding the optical properties of nanostructured materials demands a multifaceted approach due to their complexity and diverse phenomena. These materials usually have interesting transmittance and reflectance properties, remarkable scattering effects and polarization dependent effects due to their unique morphology. This study explores materials with very different natures by optical methods, showcasing the variety of optical materials and the techniques used to study them. The simplest materials studied were Silicon dioxide films grown over crystalline Silicon by reflectance measurements. Then, the complex structures in the wings of the Episcada hymenaea translucent butterfly and the Saturniidae Heliconisa pagenstecheri common moth were studied employing measurements in the UV-vis range, with particularly striking polarization conversion effects observed. Lastly, optical techniques were applied to the study of unidimensional (1D) nanostructures, ZnO nanorods sensitized with SnS, were examined for their transmittance, reflectance, absorption, and polarization properties. Interesting effects related to the morphology of the nanostructures—and the formation of nanotubes—were observed, paving the way for future work on nanostructured semiconductors. To interpret the results effectively, a mathematical tool capable of handling multilayered nanostructures,the transfer matrix method,was implemented, providing insights into specific phenomena observed in the samples. The application of this tool underscores the whole work, which ultimately showcases the potential, and the limitations, of the technique.
Los materiales nanoestructurados, aquellos con al menos una dimensión física del orden de los 100 nm o menos, han impulsado avances tecnológicos significativos en las últimas décadas. Su capacidad para manipular las interacciones entre la luz y la materia a esta escala, permitiendo un control por debajo de la longitud de onda, ha impulsado a la fotónica como uno de los principales campos de investigación en los últimos tiempos. Aunque los materiales ópticos nanoestructurados naturales son abundantes, no fue hasta el reciente desarrollo de técnicas de síntesis que permitieron el control nanométrico de materiales sintéticos. Entre estos materiales, las nanoestructuras multicapa, con espesor confinado a la nanoescala, han surgido como un elemento clave en tecnologías fundamentales como los dispositivos fotovoltaicos para la generación de energía renovable. La comprensión de las propiedades ópticas de los materiales nanoestructurados demanda un enfoque multifacético debido a su complejidad y la diversidad de fenómenos. Estos materiales suelen tener propiedades interesantes de transmitancia y reflectancia, efectos de dispersión notable y propiedades dependientes de la polarización debido a su morfología única. Este estudio explora materiales con naturalezas muy diferentes mediante métodos ópticos, mostrando la variedad de materiales ópticos y las técnicas utilizadas para estudiarlos. Los materiales más simples estudiados fueron películas de dióxido de Silicio crecidas sobre Silicio cristalino mediante medidas de reflectancia. Luego, se estudiaron las estructuras complejas en las alas de la mariposa translúcida Episcada hymenaea y la polilla común Saturniidae Heliconisa pagenstecheri, ambas autóctonas del Uruguay, empleando medidas en el rango UV-vis, en las que se observaron efectos de conversión de polarización particularmente llamativos. Por último, se aplicaron técnicas ópticas al estudio de nanoestructuras unidimensionales (1D), se examinaron nanovarillas de ZnO sensibilizadas con SnS, para conocer sus propiedades de transmitancia, reflectancia, absorción y polarización. Se observaron efectos interesantes relacionados con la morfología de las nanoestructuras—en particular la formación de nanotubos—abriendo el camino para futuros trabajos en semiconductores nanoestructurados. Para interpretar los resultados de manera efectiva, se implementó una herramienta matemática capaz de manejar nanoestructuras multicapa, el método de matriz de transferencia, que proporciona información sobre algunos fenómenos específicos observados en las muestras. La aplicación de esta herramienta subyace todo el trabajo, que en última instancia muestra el potencial y las limitaciones de la técnica.
2024 | |
Becas de Posgrado Nacional 2022. POS_NAC_2022_1_173968. Proyecto : Caracterización óptica de nanomateriales con propiedades anisotrópicas. | |
Nanotechnology Optics Photonics Morphology Modeling Nanotecnología Optica Fotónica Morfología Modelado |
|
Inglés | |
Universidad de la República | |
COLIBRI | |
https://hdl.handle.net/20.500.12008/43976 | |
Acceso abierto | |
Licencia Creative Commons Atribución - No Comercial - Sin Derivadas (CC - By-NC-ND 4.0) |
Sumario: | Nanostructured materials, those with at least one physical dimension of the order of 100 nm or less, have driven significant technological advancements in the last decades. Their ability to manipulate light-matter interactions at this scale, enabling control below the wavelength, has propelled photonics into on of the leading research fields. While natural nanostructured optical materials abound, it was not until the recent development of synthesis techniques that allowed custom fabrication. Among the nanoscale materials, multilayered nanostructures, with thickness confined to the nanoscale, have emerged as a key element in fundamental technologies such as photovoltaic devices for clean energy generation. Understanding the optical properties of nanostructured materials demands a multifaceted approach due to their complexity and diverse phenomena. These materials usually have interesting transmittance and reflectance properties, remarkable scattering effects and polarization dependent effects due to their unique morphology. This study explores materials with very different natures by optical methods, showcasing the variety of optical materials and the techniques used to study them. The simplest materials studied were Silicon dioxide films grown over crystalline Silicon by reflectance measurements. Then, the complex structures in the wings of the Episcada hymenaea translucent butterfly and the Saturniidae Heliconisa pagenstecheri common moth were studied employing measurements in the UV-vis range, with particularly striking polarization conversion effects observed. Lastly, optical techniques were applied to the study of unidimensional (1D) nanostructures, ZnO nanorods sensitized with SnS, were examined for their transmittance, reflectance, absorption, and polarization properties. Interesting effects related to the morphology of the nanostructures—and the formation of nanotubes—were observed, paving the way for future work on nanostructured semiconductors. To interpret the results effectively, a mathematical tool capable of handling multilayered nanostructures,the transfer matrix method,was implemented, providing insights into specific phenomena observed in the samples. The application of this tool underscores the whole work, which ultimately showcases the potential, and the limitations, of the technique. |
---|