Tutorial Review: X-ray Mapping in Electron-Beam Instruments

Abstract

This review traces the development of X-ray mapping from its beginning 50 years ago through current analysis procedures that can reveal otherwise obscure elemental distributions and associations. X-ray mapping or compositional imaging of elemental distributions is one of the major capabilities of electron beam microanalysis because it frees the operator from the necessity of making decisions about which image features contain elements of interest. Elements in unexpected locations, or in unexpected association with other elements, may be found easily without operator bias as to where to locate the electron probe for data collection. X-ray mapping in the SEM or EPMA may be applied to bulk specimens at a spatial resolution of about 1 mm. X-ray mapping of thin specimens in the TEM or STEM may be accomplished at a spatial resolution ranging from 2 to 100 nm, depending on specimen thickness and the microscope. Although mapping has traditionally been considered a qualitative technique, recent developments demonstrate the quantitative capabilities of X-ray mapping techniques. Moreover, the long-desired ability to collect and store an entire spectrum at every pixel is now a reality, and methods for mining these data are rapidly being developed.

A novel Mo-W interlayer approach for CVD diamond deposition on steel

“…It is worth mentioning that the EDX spectra obtained doesn't possess as high spatial resolution as would be desirable. 34 It is reasonable to assume that the distribution contour plots between the elements are even sharper than the obtained profile in Fig. 6.…”

Advanced Methods of Electron Microscopy in Catalysis Research

“…The question that now arises is: Can some chemical information be obtained about clusters this size? The first point that should be very clear in this chapter is that while X-ray EDS and EELS ( Friel and Lyman, 2006;Stroppa et al, 2012) are great techniques to accomplish chemical mapping and can be used in catalysis, as shown in other sections of this work, they are very limited for small clusters. Indeed, in many relevant cases the catalysts will be ultra-disperseddthat is, they will contain a few atoms or their size will be a few nanometers.…”

Wavelength dispersive X‐ray spectroscopy of thick and thin samples for electron microscopes

“…The most adopted X-ray spectroscopy is energy dispersive X-ray spectroscopy (EDS) using semiconductor detectors, owing to its compactness, high detection efficiency, and easy operation. [1,2] Meanwhile, wavelength dispersive X-ray spectroscopy (WDS) surpasses EDS at high energy resolution, detection limit, and its ability to detect light elements. WDS is usually installed in electron probe micro analyzers (EPMAs), [3,4] not in scanning electron microscopes (SEMs) or in transmission electron microscopes (TEMs).…”