High-spatial-resolution energy dispersive spectroscopy

HR-EDS high-spatial-resolution energy dispersive spectroscopy... 

XAS requires synchrotron radiation and a relatively large amount of material but no vacuum condition. On the other hand, EELS can be performed directly using an electron spectrometer fitted to a scanning transmission electron microscope (STEM). Here, the main advantage is the high spatial resolution attainable. (The incident electron beam can be as. small as I nm in diameter.) EELS can also be coupled with conventional transmission electron microscope (TEM) facilities and particularly high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS). 

Energy-dispersive X-ray (EDX) spectroscopy utilizes the characteristic spectrum of X-rays that is emitted by a sample, following initial excitation by the high-energy electron beam. Information about the elemental composition of the sample can be obtained, where the spatial resolution is determined by the probe size, any beam broadening occurring within the specimen, and the effects of any backscattered electrons on the specimen around the point of analysis. EDX is relatively simple and can be used to provide rapid qualitative microanalysis. Quantitative elemental analysis can also be achieved, with an... 

While the spatial resolution of AES, XPS and SIMS continues to improve, atomic scale analysis can only be obtained by transmission electron microscopy (TEM), combined with energy dispersive X-ray spectroscopy (EDX) or electron energy loss spectroscopy (EELS). EDX detects X-rays characteristic of the elements present and EELS probes electrons which lose energy due to their interaction with the specimen. The energy losses are characteristic of both the elements present and their chemistry. Reflection high-energy electron diffraction (RHEED) provides information on surface slmcture and crystallinity. Further details of the principles of AES, XPS, SIMS and other techniques can be found in a recent publication [1]. This chapter includes the use of AES, XPS, SIMS, RHEED and TEM to study the composition of oxides on nickel, chromia and alumina formers, silicon, gallium arsenide, indium phosphide and indium aluminum phosphide. Details of the instrumentation can be found in previous reviews [2-4]. 

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