Image-spectroscopy – I. The advantages of increased spectral information for compositional EFTEM analysis

The acquisition of a series of energy-filtered TEM images over the energy-loss range of interest creates a three-dimensional data set comprising both spatial and spectral information. Such an image-series contains energy-loss information not available with conventional two- or three-window methods, allowing standard techniques for quantitative EELS analysis to be applied to extracted ‘image-spectra’. The increase in spectral information enables improved ionisation edge background extrapolation and interactive image-spectrum analysis to be performed. In this paper, the many advantages of the image-spectroscopy approach are outlined by reference to an example of elemental segregation in an AlZnMgCu alloy.