The March 2011 issue of Microscopy Today contained a group of articles describing various types of surface analysis—measurements of elements and molecules from the top few atomic layers of a solid surface. Those articles featured basic explanations of X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and low-energy ion scattering (LEIS). Some of the articles showed the imaging and depth profiling capabilities of these methods.
The present issue is an update of these surface analysis topics five years later. Guest Editor Don Baer organized this set of articles with an eye toward showing how the above methods, plus scanning transmission electron microscopy (STEM) and atom probe tomography (APT), complement one another to solve difficult practical problems. Baer introduces this surface analysis issue with an overview of the techniques and their current capabilities. Cecil Powell shows that use of XPS has grown significantly over the last 25 years and now appears in ten times more publications per year than either Auger or SIMS. Anderton and Gamble show how different types of SIMS instruments can provide images of the distributions of molecular species from biological specimens. Wang et al. show how STEM and SIMS can complement each other in in-situ analyses of functioning batteries. Finally, Baer et al. show how XPS can play an important role in the effort to determine compositions and thicknesses of multiple shells within nanoparticles exhibiting core-shell structures.
What’s the take-away from the present group of articles? I learned the following: (a) useful chemical imaging is now available for most surface analysis methods, (b) the essential ultra-high vacuum specimen environment is now so routine that it is hardly mentioned, (c) well-designed in-situ experiments connected to surface analysis instruments can yield answers to real-world problems, and (d) tough analysis problems demand complementary techniques, easy-to-use modeling software, and clever experimental design.
I thank our guest editor, Don Baer, and all the authors of these articles. I look forward to further developments during the next five years.
