STEM electron tomography of gold nanostructures

J. C. HERNANDEZ; M.S.MORENO; E.A.CORONADO; P.A.MIDGLEY

Achen, Alemania

Conferencia; EMC 2008 14th European Microscopy Congress; 2008

European Microscopy Association

The electronic and optical properties of many nanoparticles can depend critically on their size and morphology  As such, the morphological control of noble metal nanoparticles, technologically important in many fields such as catalysis, optics and surface enhanced Raman spectroscopy, has become of great interest. Metallic core-shell nanostructures have attracted attention since it is possible to enhance physical and chemical properties that cannot be obtained in single-component nanoparticles. Their plasmonic properties can be tuned with nanoparticle geometry (size and shape) and dielectric environment to such extent that a very small change in their geometry leads to dramatic changes in their optical properties . Knowledge of the 3D morphology as well as the precise thickness of the shell is needed in order to understand the unusual physico-chemical properties of these core-shell nanostructures. Here we apply STEM based electron tomography, a technique well suited to materials science applications ,to achieve a full 3D analysis of gold and gold-silver core-shell nanostructures.Tomographic reconstruction allows 3D visualization of the nanoparticle shape and enables measured opto-electronic properties to be related to the particle morphology. In particular, we would like to understand variation in the surface plasmon resonance as a function of core-shell dimension and composition