EELS in monochromated and Cs probe corrected TEM: a relevant alternative to soft-XAS in synchrotron to investigate nanostructures

Up to recently, soft-X-Ray Absorption Spectroscopy (SXAS) performed in the context of a 3rd generation Synchrotron Radiation Source (SRS), was the natural experimental way to probe element partial density of empty electronic states. Thanks to the coupling to high resolution monochromator, energy resolution around 0.1 eV is currently achieved in XAS spectra, in an energy range as low as 100–1000 eV. Nowadays, with the development of monochromator and electron probe corrector, 0.1eV energy resolution with beam current ten times higher than in traditional machines can also be obtained in the context of Transmission Electron Microscopes. Thus, EELS in monochromated and Cs probe-corrected FEG-TEM is becoming a reliable alternative to soft-XAS. It is even becoming one of the most relevant tools to investigate nanostructures, because of the sub-nanometer spatial resolution achieved in FEG-TEM.