Electron Energy Loss Spectroscopy of Metallic Nanostructures and Carbon Nanotubes

Abstract

<p>In this thesis, a modern transmission electron microscope is used to perform high-resolution electron energy loss studies of metallic nanostructures and carbon nanotubes.</p> <p>The remarkable optical properties of metallic nanostructures arise from the excita- tion of surface plasmons. With improved instrumentation, surface plasmon resonances are imaged in a variety of nanostructures, enabling a greater understanding of their behaviour in nanoscale systems. It is shown that surface plasmons set up multiple high order resonances in silver nanorods, and they freely propagate around sharp corners in silver nanowires. It is also demonstrated that silver nanorice structures resonate in a similar manner to nanorods, despite the high density of stacking faults in the structure. Finally, a complementary structural pair is found to resonate in a complementary fashion, in agreement with Babinet’s principle.</p> <p>Carbon nanotubes exhibit unique physicochemical properties that have led to their use in a variety of novel materials science applications. Despite rapid progress in the theoretical and experimental investigation of carbon nanotubes, techniques capable of studying the structural and electronic properties of individual tubes are limited. Here, it is demonstrated that the spectral signature of carbon can be used to identify the electronic character of individual single-walled carbon nanotubes. In addition, a new technique is used to map bonding anisotropy in a multi-walled carbon nanotube.</p> <p>Also presented in this thesis is the design and construction of a unique laser-TEM system. Early results from the system include in-situ measurements of laser-induced structural and electronic distortions in individual carbon nanotubes.</p>