Characterization of nanoparticles by microbeam analysis and microscopy

Abstract

The analysis of selected, individual nanoscale particles represents the limit of performance for the most advanced microanalytical techniques. Ion beam methods are inadequate for objects with dimensions below 100 nm because of limitations on the number of atoms that can be ionized and collected. By using near-field optical techniques, photon beam methods are just beginning to gain the spatial resolution necessary to penetrate the 100 nm barrier. Electron beam techniques such as low voltage (< 5 kV) scanning electron microscopy and high voltage (≥100 kV) analytical electron microscopy are highly effective in the sub-100 nm size regime. Electron-excited X-ray spectrometry can provide accurate elemental analysis in both energy regimes. At high energy, electron energy loss spectrometry (EELS) can also be utilized, augmenting elemental analysis with molecular (compound) information. Analytical masses as small as 1 zg can be characterized with EELS.