Microanalysis of light elements by simultaneous x-ray and electron spectrometry

Recent availability of ultrathin-window (UTW) x-ray detectors capable of analyzing elements as light as carbon or boron in transmission/scanning transmission electron microscopes allows energy-dispersive x-ray spectrometry (EDXS) to be used as an alternative to electron energy loss spectrometry (EELS) for microanalysis of most light elements. Nevertheless, the complementary information available from EELS and the ease of acquiring EELS and EDXS data simultaneously, so that the analyses refer to essentially the same specimen region, crystal orientation, and electron beam conditions, make it advantageous to use both analytical methods. This paper describes advantages of simultaneous EDXS/EELS data acquisition; compares the measured and calculated efficiencies of a UTW x-ray detector for light elements including carbon, oxygen, and nitrogen; considers the present state of quantitative EELS analysis; and describes an important electron beam damage effect that limits the spatial resolution attainable by both EDXS and EELS in microanalysis of light element compounds