AEM-based XEDS/EELS microanalysis: A materials science perspective

Abstract

In 1966 Elad and Nakamura first described the use of a solid state device made out of silicon for use as a detector system in discriminating x-ray photons of differing energy. Since that time the growth and applications of the now universally accepted Si(Li) detector and its analysis technique X-ray Energy Dispersive Spectroscopy (XEDS) on electron column devices has been almost phenomenal. Nearly 50% of the electron microscopes sold today are routinely equipped with this peripheral for use as either a qualitative and/or quantitative analysis tool. An even older analytical technique Electron Energy Loss Spectroscopy (EELS) was first explored in the early 1940's by Hillier and Baker, and then rejuvenated in the late 1960's by a variety of laboratory's worldwide. For both of these analytical methodologies, the applications run the gamut from such routine aspects as determining the nominal composition of a specimen, through the more specific application such as measurement of elemental segregation at boundaries and interfaces, to the more esoteric applications which, for example, attempt to determine the relative atomic occupancy of sites within a crystalline lattice. Each of these modes of operations is well within the grasp of any microscopist once he or she fully appreciates the methodology and limitations of the instrumentation, technique and data analysis procedure.