Resumen de Plasmonic nanoengineering in hollow metal nanostructures: an electron energy-loss spectroscopy study
Aziz Genç
Metallic nanostructures have received great attention due to their ability to generate surface plasmon resonances, which are the collective oscillations of conduction band electrons in a metal excited by an electromagnetic field. Ever-increasing interest in plasmonic metal nanostructures has emerged into the field of \textit{plasmonics}, which can be defined as the science and technology of generation, control and manipulation of excitations resulted by the light-matter interactions. Plasmonic nanostructures have been used in many different applications spanning over the fields of biology, physics, chemistry, engineering and medicine. For instance, they are widely used in sensing, surface enhanced Raman spectroscopy (SERS), plasmon-enhanced solar cells, photodetectors, drug delivery and cancer therapy as well as nanolasers, invisibility cloaks and quantum computing. It is very-well known that plasmonic properties of metallic nanostructures are greatly affected by different parameters such as the size, shape, composition and local environment. Thus, understanding and manipulating the plasmonic properties at the nanoscale is essential to fabricate devices with the desired features. In this thesis manuscript, we present a detailed characterization study on the plasmonic properties hollow AuAg nanostructures by using electron energy-loss spectroscopy (EELS) technique. Hollow nanostructures are known to have enhanced plasmonic properties compared to their solid counterparts due to the coupling of inner and outer plasmon resonances. This study involves the first examples of spatially resolved plasmon mapping in hollow AuAg nanostructures such as nanoboxes and nanotubes, both in 2D and 3D. This thesis manuscript is divided into six chapters. Chapter 1 is the introduction, which includes the theoretical background of surface plasmon resonances, the reviews of different parameters that affects the plasmonic properties of metal nanostructures, the application areas of plasmonic nanostructures and characterization techniques used to determine the plasmonic properties. In Chapter 2, details of the methodology are presented. Experimental results and accompanying simulations are presented in Chapters 3, 4 and 5, where we perform a detailed characterization and modeling studies on complex metal nanostructures. Finally, Chapter 6 includes the general conclusions of the whole thesis and some future works that are already on-going or planned to be done in the near future.
