Studies of Electronic Excitations in Nano-Materials by Spatially Resolved Electron Energy Loss Spectroscopy

摘要

The electronic excitations of nano-materials are investigated by spatially resolved electron energy loss spectroscopy and energy dispersive X-ray spectrometer used in conjunction with scanning transmission electron microscopy (STEM-EELS/EDS) in order to further study the microstructure, physical and chemical properties. When fast electrons pass through the materials, they will generate various solid state excitations with bulk and surface characteristics via Coulomb interactions and lose energies accordingly. Typical bulk excitations include bulk plasmons (BPs), Cherenkov radiations, band gap and inter band transitions and inner-shell ionizations. Surface excitations with propagation wavevector confined along the surface include surface plasmons (SPs), surface guided mode and surface exciton polaritons (SEPs). These excitations play a very important role in the properties of materials.