Electron Probe X-Ray Spectral Analysis of Nanoparticles

Resumo

Two approaches for improving the resolution via electron probe X-ray spectral microanalysis (EPXRSMA) are considered for the characterization of the nanoparticle composition. The first approach implies the use of L and M series as the analytical ultrasoft X-ray lines of the characteristic radiation of elements to be detected, which are excited by the low-energy electrons (less than 5 keV). The quantitative EPXRSMA, involving a new way for calculating the matrix element correction, is elaborated for this approach. The extrapolation route for the construction of the calibration characteristic is extended to all elements with Z > 40. The second approach is based on the use of the analytical signal caused by only the excitation by electrons of the probe. The achieved lateral resolution is about 2 nm, and the depth resolution is 20–60 nm. The minimal determined mass of the substance is approximately (1–2.5) × 10^–21 g, which corresponds to 10–30 atoms of the detected elements.